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Impact of Weather on Marathon-Running Performance
Abstract
Marathon running performance slows in warm weather conditions, but the quantitative impact of weather has not been established.
To quantify the impact of weather on marathon performance for different populations of runners.
Marathon results and weather data were obtained for the Boston, New York, Twin Cities, Grandma's, Richmond, Hartford, and Vancouver Marathons for 36, 29, 24, 23, 6, 12, and 10 yr, respectively. The race results were broken into quartiles based on the wet-bulb globe temperature (Q1 5.1-10 degrees C, Q2 10.1-15 degrees C, Q3 15.1-20 degrees C, and Q4 20.1-25 degrees C). Analysis of the top three male and female finishers as well as the 25th-, 50th-, 100th-, and 300th-place finishers were compared with the course record and then contrasted with weather.
Marathon performances of top males were slower than the course record by 1.7 +/- 1.5, 2.5 +/- 2.1, 3.3 +/- 2.0, and 4.5 +/- 2.3% (mean +/- SD) for Q1-Q4, respectively. Differences between Q4 and Q1, Q2, and between Q3, and Q1 were statistically different (P < 0.05). The top women followed a similar trend (Q1 3.2 +/- 4.9, Q2 3.2 +/- 2.9, Q3 3.8 +/- 3.2, and Q4 5.4 +/- 4.1% (mean +/- SD)), but the differences among quartiles were not statistically significant. The 25th-, 50th-, 100th-, and 300th-place finishers slowed more than faster runners as WBGT increased. For all runners, equivalence testing around a 1% indifference threshold suggests potentially important changes among quartiles independently of statistical significance.
There is a progressive slowing of marathon performance as the WBGT increases from 5 to 25 degrees C. This seems true for men and women of wide ranging abilities, but performance is more negatively affected for slower populations of runners.
... Runner's demographics, environmental conditions [1][2][3], training status [4,5], time of day [6], sunlight exposure [7,8], wind [9], and perceptual comfort [10] are some of the myriad of factors that could influence marathon performance. In particular, marathon performance suffers as temperature rises, especially if held in hot and humid climates [1,2,11]. ...
... Runner's demographics, environmental conditions [1][2][3], training status [4,5], time of day [6], sunlight exposure [7,8], wind [9], and perceptual comfort [10] are some of the myriad of factors that could influence marathon performance. In particular, marathon performance suffers as temperature rises, especially if held in hot and humid climates [1,2,11]. Furthermore, the physiological challenge of running a marathon is vastly different than running shorter distance races [12]. ...
... Climatic conditions can influence marathon performance [1][2][3]. The impact of temperature on marathon runners can be ascertained through measurements of dry bulb temperature (T db ), wet bulb temperature (T wb ), dewpoint temperature (T d ), and wet bulb globe temperature (WBGT). ...
We examined marathon performance of the same group of runners in relation to small changes in dry bulb temperature (Tdb) and wet bulb temperature (Twb) across 3 consecutive y, and investigated whether performance was poorer during an evening marathon compared with morning marathons. Marathon results were obtained from the 2017, 2018, and 2019 Standard Chartered Singapore Marathons. Tdb, Twb, Td, relative humidity, and absolute humidity were gathered for each marathon. K-means clustering and linear regressions were performed on 610 runners who participated in all three marathons. Analysis of the 610 runners’ marathon performance was contrasted with Tdb and Twb. Linear regressions were also performed on 190 runners filtered by percentile, yielding similar results. For clusters with similar Tdb from all runners K-means clustering, an increase in mean Twb by 1.5°C coincided with an increase in finishing time by 559 s (9.3 min) (p < 0.033). Twb hinders marathon performance more than Tdb, with each percentage rise in Tdb and Twb resulting in an increase in net time by 7.6% and 39.1%, respectively (p < 0.025). Male and female runners’ response to Tdb and Twb changes were similar (overlap in 95% confidence intervals for the respective regression coefficients). In conclusion, small variations in environmental parameters affected marathon performance, with Twb impairing marathon performance more than Tdb. Marathon performance was likely better in the morning than evening, possibly due to time of day differences, along with unfavorable Tdb that superseded training effects and the effects of lower Twb.
... Evaporation is the predominant heat transfer mechanism during land-based exercise modalities (Sawka, Cheuvront, & Kenefick, 2012). Therefore, relatively low ambient temperatures are optimal for athletic performance in endurance running (Ely, Cheuvront, Roberts, & Montain, 2007) and cycling (Galloway & Maughan, 1997). Conversely, for swimmers who train and compete in water, the effect of the environment on thermoregulation and performance is not well-defined. ...
... Numerous recent recommendations and guidelines have been published to assist athletes training and competing under heat stress (Bergeron et al., 2012;Périard, Stephenson, Goosey-Tolfrey, Nikopoulos, & Migliorini, 2020;Racinais et al., 2015). Climatic conditions reported in published studies of training and competition are often reported from meteorological data rather than directly from the specific geographical site where the outdoor performance is Roberts, et al., 2007;Guy et al., 2015;Hue et al., 2013;Hue, Monjo, & Riera, 2015;Racinais et al., 2019). For example, marathons can occur in a range of conditions from high to low heat illness risk dependent on geographical location (El Helou et al., 2012;Ely, Cheuvront, Roberts, et al., 2007). ...
... Climatic conditions reported in published studies of training and competition are often reported from meteorological data rather than directly from the specific geographical site where the outdoor performance is Roberts, et al., 2007;Guy et al., 2015;Hue et al., 2013;Hue, Monjo, & Riera, 2015;Racinais et al., 2019). For example, marathons can occur in a range of conditions from high to low heat illness risk dependent on geographical location (El Helou et al., 2012;Ely, Cheuvront, Roberts, et al., 2007). Reduction in performance and heat illness incidence during marathons also often occur in conditions much cooler than most laboratory studies (Ely, Cheuvront, Roberts, et al., 2007). ...
The impact of environmental conditions on exercise performance in elite athletes has been explored extensively in the laboratory. Research is yet to determine the effect of the environment on performance in applied settings and novel non-thermally mediated ergogenic aids for endurance exercise in the heat have recently been proposed but are poorly understood and have not been tested in an endurance trained population. The studies in this thesis determined the effect of divergent environmental conditions on outdoor swimming performance in elite swimmers and the effect of paracetamol on the performance of trained triathletes during an endurance cycling bout in hot and humid conditions. There was no effect of the environmental conditions on the core temperature or performance of elite swimmers but skin temperature and thermal sensation differed between conditions. Paracetamol had no effect on endurance time trial performance and core and skin temperature, heart rate and thermal perception was unaffected during steady state and time trial cycling. Overall, the findings reiterate the importance of assessing thermal stress and ergogenic aids in ecologically valid settings using well planned applied study designs. Thermal stress was found to be specific to exercise mode, environmental conditions and exercise intensity and trained endurance athletes should continue to use thermally mediated pre- and per-cooling methods as non-thermally mediating ergogenic aids may not reduce core and skin temperature or thermal perception effectively during endurance exercise bouts.
... Canadian national teams, for example, use this method. This is not ideal for outdoor sports, however, as athlete performance is heavily influenced by environmental factors (Galloway and Maughan 1997;Peiser and Reilly 2004); weather conditions such as humidity, elevation, temperature, wind and water properties are known to affect sports performance by altering the efficiency and physiological responses of athletes (Diafas et al. 2006;Ely et al. 2007;Galloway and Maughan 1997). WBT is often set under favourable weather conditions (e.g. ...
... WBT is often set under favourable weather conditions (e.g. tail wind, with current, hot water temperature, altitude. . . ) (Diafas et al. 2006;Ely et al. 2007;Galloway and Maughan 1997;Peiser and Reilly 2004), posing a challenge in establishing a fair standard. Efforts have been made to decipher the impact of weather conditions on performance in distance running and cycling by determining reduction in performance (Ely et al. 2007;Galloway and Maughan 1997), but to date only a few studies have investigated this relationship in the context of water sports, specifically in the context of kayak races (Barber 2018;Higgens et al. 2016); these studies have tried to take into account the effects of wind in race times, but fail to account for other conditions. ...
... tail wind, with current, hot water temperature, altitude. . . ) (Diafas et al. 2006;Ely et al. 2007;Galloway and Maughan 1997;Peiser and Reilly 2004), posing a challenge in establishing a fair standard. Efforts have been made to decipher the impact of weather conditions on performance in distance running and cycling by determining reduction in performance (Ely et al. 2007;Galloway and Maughan 1997), but to date only a few studies have investigated this relationship in the context of water sports, specifically in the context of kayak races (Barber 2018;Higgens et al. 2016); these studies have tried to take into account the effects of wind in race times, but fail to account for other conditions. ...
Rowing needs a standardized Gold Medal Standard (GMS) to clearly compare performance across boat classes in competition. Here, we report a method to factor out environmental effects, developing a fairer GMS for individual rowing events. We used results from World Rowing Championships and Olympics Games (2005–2016) to calculate the difference between the fastest winning time of the day and other event winning times on the same day. From this, we calculated a prognostic GMS time for each event via repeated k-fold cross-validation linear regression. Then, we compared these values with the 10-year average winning time and the World Best Time (WBT). We repeated this process to develop prognostic podium standard (PS) times. The prognostic GMS times (RMSE = 9.47; R2 = 0.875) were universally slower than the WBT (current GMS) by 6.2 s on average but faster than the 10-year average by 12.3 s. The prognostic PS times (RMSE = 10.5; R2 = 897) were also slower than the WBT but faster than the 10-year average, by 12.2 and 6.3 s respectively. Our time-difference prediction model based on historical data generates non-outlier prognostic times. With the utilization of relative time difference, this approach promises a selection standard independent of environmental conditions, easily applicable across different sports.
... Canadian national teams, for example, use this method. This is not ideal for outdoor sports, however, as athlete performance is heavily influenced by environmental factors (Galloway and Maughan 1997;Peiser and Reilly 2004); weather conditions such as humidity, elevation, temperature, wind and water properties are known to affect sports performance by altering the efficiency and physiological responses of athletes (Diafas et al. 2006;Ely et al. 2007;Galloway and Maughan 1997). WBT is often set under favourable weather conditions (e.g. ...
... WBT is often set under favourable weather conditions (e.g. tail wind, with current, hot water temperature, altitude. . . ) (Diafas et al. 2006;Ely et al. 2007;Galloway and Maughan 1997;Peiser and Reilly 2004), posing a challenge in establishing a fair standard. Efforts have been made to decipher the impact of weather conditions on performance in distance running and cycling by determining reduction in performance (Ely et al. 2007;Galloway and Maughan 1997), but to date only a few studies have investigated this relationship in the context of water sports, specifically in the context of kayak races (Barber 2018;Higgens et al. 2016); these studies have tried to take into account the effects of wind in race times, but fail to account for other conditions. ...
... tail wind, with current, hot water temperature, altitude. . . ) (Diafas et al. 2006;Ely et al. 2007;Galloway and Maughan 1997;Peiser and Reilly 2004), posing a challenge in establishing a fair standard. Efforts have been made to decipher the impact of weather conditions on performance in distance running and cycling by determining reduction in performance (Ely et al. 2007;Galloway and Maughan 1997), but to date only a few studies have investigated this relationship in the context of water sports, specifically in the context of kayak races (Barber 2018;Higgens et al. 2016); these studies have tried to take into account the effects of wind in race times, but fail to account for other conditions. ...
Rowing needs a standardized Gold Medal Standard (GMS) to clearly compare performance across boat classes in competition. Here, we report a method to factor out environmental effects, developing a fairer GMS for individual rowing events. We used results from World Rowing Championships and Olympics Games (2005–2016) to calculate the difference between the fastest winning time of the day and other event winning times on the same day. From this, we calculated a prognostic GMS time for each event via repeated k-fold cross-validation linear regression. Then, we compared these values with the 10-year average winning time and the World Best Time (WBT). We repeated this process to develop prognostic podium standard (PS) times. The prognostic GMS times (RMSE=9.47; R2=0.875) were universally slower than the WBT (current GMS) by 6.2 seconds on average but faster than the 10-year average by 12.3 seconds. The prognostic PS times (RMSE=10.5; R2 = 897) were also slower than the WBT but faster than the 10-year average, by 12.2 and 6.3 seconds respectively. Our time-difference prediction model based on historical data generates non-outlier prognostic times. With the utilization of relative time difference, this approach promises a selection standard independent of environmental conditions, easily applicable across different sports.
... Indeed, an analysis investigating marathon race times of the World Marathon Major races for Boston, London, Berlin, Chicago, and New York showed that weather, rather than course, had an effect on race times (Maffetone et al., 2017). Of all the weather variables, ambient temperature seems to have the highest influence on marathon race times (Zhang et al., 1992;Ely et al., 2007b). There is a lot of evidence that performance in a marathon is impaired with increasing temperature (Trapasso and Cooper, 1989;Ely et al., 2007b;González-Alonso, 2007;El Helou et al., 2012). ...
... Of all the weather variables, ambient temperature seems to have the highest influence on marathon race times (Zhang et al., 1992;Ely et al., 2007b). There is a lot of evidence that performance in a marathon is impaired with increasing temperature (Trapasso and Cooper, 1989;Ely et al., 2007b;González-Alonso, 2007;El Helou et al., 2012). The optimum temperature for a fast marathon race time is generally ∼10-12 • C (Ely et al., 2007b;Maughan, 2010) or even as low as ∼8 • C (Trapasso and Cooper, 1989). ...
... There is a lot of evidence that performance in a marathon is impaired with increasing temperature (Trapasso and Cooper, 1989;Ely et al., 2007b;González-Alonso, 2007;El Helou et al., 2012). The optimum temperature for a fast marathon race time is generally ∼10-12 • C (Ely et al., 2007b;Maughan, 2010) or even as low as ∼8 • C (Trapasso and Cooper, 1989). ...
The influence of environmental conditions has been investigated for different marathon races, but not for the Berlin Marathon, the fastest marathon race course in the world. The aim of this study was to investigate the potential influence of environmental conditions such as temperature, precipitation, sunshine, and atmospheric pressure on marathon race times in the Berlin Marathon since its first event in 1974–2019. A total of n = 882,540 valid finisher records were available for analysis, of which 724,135 correspond to male and 158,405 to female runners. We performed analyses regarding performance levels considering all finishers, the top 3, the top 10, and the top 100 women and men. Within the 46 years of Berlin marathons under study, there was some level of precipitation for 18 years, and 28 years without any rain. Sunshine was predominant in 25 of the events, whilst in the other 21, cloud cover was predominant. There was no significant trend with time in any of the weather variables (e.g., no increase in temperature across the years). Overall runners became slower with increasing temperature and sunshine duration, however, elite runners (i.e., top 3 and top 10) seemed to run faster and improved their race times when the temperature increased (with women improving more than men). Top 10 women seemed to benefit more from increasing temperatures than top 10 males, and male top 100 runners seemed to benefit more from increasing temperatures than female top 100 runners. In the top three sub-group, no differences were observed between male and female correlations. In summary, in marathoners competing in the Berlin Marathon between 1974 and 2019, increasing temperatures and sunshine duration showed a different effect on different performance levels where overall runners (i.e., the general mass of runners) became slower with increasing temperature and sunshine duration, but elite runners (i.e., top 3, top 10) became faster with increasing temperatures where sex differences exist.
... The weather variable with the strongest influence on marathon race performance is ambient temperature (Suping et al., 1992;Ely et al., 2007a,b). In elite marathon runners, the ideal temperatures seem to be around 10-12°C, both in men and women (Martin and Buoncristiani, 1999;Ely et al., 2007b); however, even temperatures as low as around 8°C can lead to fast marathon times (Trapasso and Cooper, 1989). Warm weather conditions seem to slow down marathon performances, both in men and women; however, slow runners seem to be more negatively impacted than elite runners (Ely et al., 2007b). ...
... In elite marathon runners, the ideal temperatures seem to be around 10-12°C, both in men and women (Martin and Buoncristiani, 1999;Ely et al., 2007b); however, even temperatures as low as around 8°C can lead to fast marathon times (Trapasso and Cooper, 1989). Warm weather conditions seem to slow down marathon performances, both in men and women; however, slow runners seem to be more negatively impacted than elite runners (Ely et al., 2007b). ...
... Female athletes may be performing better in cooler ambient temperatures than men, but there is no definite evidence for this (Martin and Buoncristiani, 1999;Ely et al., 2007b). It has been shown that thermal comfort and rating of perceived exertion were significantly higher during exercise in males than in females with ice slurry ingestion (Iwata et al., 2020). ...
The "Berlin Marathon" is the fastest marathon racecourse in the world and has witnessed 11 world records (WRs; eight in men and three in women). Weather conditions can have an important impact on race time and we therefore examined the influence of environmental conditions (i.e., temperature, sunshine, precipitation, barometric pressure, and cloud cover) on WRs and elite (i.e., winner, top three and top 10 finishers) marathon performances of men and women at the "Berlin Marathon" between 1974 and 2019. Average world record marathon times in men were 2:03:52 ± 0:01:19 h:min:s and 2:25:05 ± 0:08:25 h:min:s in females (p < 0.05). Male competitions were held 44 times (mean winning time: 2:09:48 ± 0:09:15 h:min:s) and female competitions 41 times (mean winning time: 02:30:35 ± 0:19:09 h:min:s; p < 0.05). World record performances were set at mean temperatures of 18.61 ± 2.59°C for men and 13.07 ± 4.01°C for women (p > 0.05). The ideal environmental conditions for world record performances for men were temperatures of 18.61°C (p > 0.05), sunny, mostly dry days, with higher atmospheric pressure and little cloud cover (all p > 0.05). In women, ideal conditions for world records performances were temperatures of 13.07°C (p > 0.05), with low atmospheric pressure (p > 0.05), but significantly more rain (p < 0.05), and with no sunshine (p < 0.05) and cloud cover (p < 0.05). With elite performances, the ideal temperatures were of 17.36 ± 4.33°C for men and 17.93 ± 4.07°C for women (p > 0.05), with little to no rain, and moderate cloud cover and sunshine (p > 0.05). In summary, novel findings are, that environmental conditions in world records performances differ between men and women, with women obtaining world records in bad weather (with rain, cloud cover, and no sunshine) and men in good weather (sunny, mostly dry days, with little cloud cover). Larger sample sizes are needed to examine sex differences and environmental conditions on world record marathon performances.
... Among all the weather variables, ambient temperature seemed to have the highest influence on marathon race times (Zhang et al., 1992;Ely et al., 2007b). There is evidence that performance in a marathon race is impaired with increasing temperature (Trapasso and Cooper, 1989;Ely et al., 2007b;González-Alonso, 2007;El Helou et al., 2012). ...
... Among all the weather variables, ambient temperature seemed to have the highest influence on marathon race times (Zhang et al., 1992;Ely et al., 2007b). There is evidence that performance in a marathon race is impaired with increasing temperature (Trapasso and Cooper, 1989;Ely et al., 2007b;González-Alonso, 2007;El Helou et al., 2012). The optimum temperature for a fast marathon race time is generally at ∼10-12 • C (Ely et al., 2007a;Maughan, 2010) or even lower at ∼8 • C (Trapasso and Cooper, 1989). ...
... It is well-known that marathon race times are impaired with increasing temperatures (Trapasso and Cooper, 1989;Cheuvront and Haymes, 2001;Ely et al., 2007b;González-Alonso, 2007;Maughan, 2010;El Helou et al., 2012;Nikolaidis et al., 2019). The temperature on race day has, however, a different influence on slower and faster runners (Montain et al., 2007;Ely et al., 2008;El Helou et al., 2012) where the optimum temperature for a fast marathon race time may be lower for faster runners than for slower runners (Maughan, 2010). ...
The effect of different environmental conditions such as temperature, wind, barometric
pressure, and precipitation has been well investigated in elite marathoners, but not by
age categories (i.e., age group marathoners). The aim of the study was to investigate the
potential influence of environmental conditions such as temperature, precipitation, and
atmospheric pressure on marathon performance in age group marathoners competing
in the ‘Berlin Marathon’ from 1974 to 2019. A total of 869,474 valid finisher records were
available for analysis, of which 711,136 correspond to males and 158,338 to females.
The influence of temperature, atmospheric pressure, and precipitation on marathon
race times was investigated in age group marathoners grouped in 5-year-intervals.
Within the 46 years of Berlin marathons under investigation, there was some level of
precipitation for 18 years, and 28 years without any rain. Sunshine was predominant
in 25 of the events, whilst in the other 21 years, cloud cover was predominant.
Marathon race times were significantly and positively correlated with age (i.e., older
runners were slower than younger runners) where the correlation was higher for males
than for females. Marathon race times were significantly and positively correlated with
both the hours of sunshine and the daily maximum temperature. The fastest marathon
runners (meaning the minimum times) achieved the fastest race times on race days with
higher maximum temperatures (i.e., 15–30◦C). Daily maximum temperatures showed
an influence on age group marathoners from age group 35–40 years and older. Higher
precipitation levels impaired performance across most age groups. In summary, higher
daily maximum temperatures (i.e., >15◦C) and higher precipitation levels impaired
performance of master marathoners (i.e., 35–40 years and older) competing in the
‘Berlin Marathon’ in the last 45 years. Master marathoners should start in marathon
races with temperatures < 15◦C and no precipitation in order to achieve a fast marathon
race time.
Keywords: running, heat, cold, rain, performance
... Meteorological impacts on performance are often anecdotal, but a number of laboratory and marathon studies have shown that elevated temperatures over 9.9°C decrease performance (Ely et al. 2007;Helou et al. 2012;Vihma 2010;Vugts 1997). This is due to alteration in circulatory, endocrine, and thermoregulatory systems during exercise to reduce the likelihood of negative effects caused by increased internal body temperatures (Casa 1999;Miller-Rushing et al. 2012;Nadel 1990). ...
... This has been previously shown by Daniels (2014), Helou et al. (2012) and Knechtle et al. (2019) examining marathon events, where each 5 o C increase in temperature will decrease performance by up to 1.6%. This is likely due to changes in athlete's circulatory and thermoregulatory systems to maintain a stable core body temperature (Casa 1999;Ely et al. 2007;Helou et al. 2012;Miller-Rushing et al. 2012;Nadel 1990;Nybo et al. 2014;Vihma 2010;Vugts 1997;Zhao et al. 2013). Athlete's core body temperature is likely to increase at a quicker rate than the aforementioned marathon studies because of the higher intensity exercise being performed, and thus metabolic heat produced during shorter duration events (Cheuvront and Haymes 2001;Gasparetto and Nesseler 2020). ...
... Overall, these findings add additional insight into the potential role of air quality in previous research that has shown temperature to be the biggest environmental influencer on (Ely et al. 2007;Helou et al. 2012;Marr and Ely 2010). Similar results for the male races were not observed. ...
Urban air pollution can have negative short- and long-term impacts on health, including cardiovascular, neurological, immune system and developmental damage. The irritant qualities of pollutants such as ozone (O 3 ), nitrogen dioxide (NO 2 ) and particulate matter (PM) can cause respiratory and cardiovascular distress, which can be heightened during physical activity and particularly so for those with respiratory conditions such as asthma. Previously, research has only examined marathon run outcomes or running under laboratory settings. This study focuses on elite 5-km athletes performing in international events at nine locations. Local meteorological and air quality data are used in conjunction with race performance metrics from the Diamond League Athletics series to determine the extent to which elite competitors are influenced during maximal sustained efforts in real-world conditions. The findings from this study suggest that local meteorological variables (temperature, wind speed and relative humidity) and air quality (ozone and particulate matter) have an impact on athletic performance. Variation between finishing times at different race locations can also be explained by the local meteorology and air quality conditions seen during races.
... The impact of meteorology on parkrun performance is often anecdotal information, however, the in uence of temperature on performance has been explored in a number of marathon and laboratory studies, which have found that athletic performance decreases as temperature increases [25,32,33]. Exercising in warmer temperatures can alter the bodies circulatory, endocrine and thermoregulatory systems, increasing the risk of adverse effects including dehydration, hyperthermia and heat stress due to reduced internal body temperature regulation [23]. ...
... Finally, several events showed no impact of temperature on performance [42][43][44]97]. Overall, this research suggests that both genders are, to an extent, impacted by meteorology, as would be expected based upon previous research [25,32,34,35]. ...
... Female and the 70-75 and 80-85 age groups showed the largest decreases in performance, the latter particularly so when relative humidity rose from 40-55% to over 85%, suggesting that they are less e cient at dispersing excess heat. Therefore, meteorology could be associated as being the main external control on athletic performance as has previously been theorised [25,[32][33][34][35]. ...
Background: Despite increased awareness of climate change and urban air pollution, little research has been performed to examine the influence of meteorology and air quality on athletic performance of the general public and recreational exercisers. Anecdotal evidence of increased temperatures and wind speeds as well as higher relative humidity conditions resulting in reduced athletic performance has been presented in the past, whilst urban air pollution can have negative short- and long-term impacts on health. Furthermore, pollutants such as Ozone, Nitrogen Dioxide and Particulate Matter can cause respiratory and cardiovascular distress, which can be heightened during physical activity. Previous research has examined these impacts on marathon runners, or have been performed in laboratory settings. Instead, this paper focuses on the potential impacts on the general public. With the rise of parkrun events (timed 5 km runs) across the UK and worldwide concerns regarding public health in relation to both air quality and activity levels, the potential influence of air quality and meteorology on what is viewed as a ‘healthy’ activity has been investigated. A weekly dataset of parkrun participants at fifteen events, located in London UK, from 2011-2016 alongside local meteorological and air quality data has been analysed.
Results[JH(G+ESLF1] : The biggest influencer on athletic performance is meteorology, particularly temperature and wind speed. Regression results between parkrun finishing times and temperature predominantly show positive relationships, supporting previous laboratory tests (p=0[JH(G+ESLF2] .01). Increased relative humidity also can be associated with slower finishing times but in several cases is not statistically significant. Higher wind speeds can also be related to slower times (p=<0.01) and in contrast to temperature and relative humidity, male participants are more influenced than female by this variable. Although air quality does influence athletic performance to an extent, the heterogeneity of pollutants within London and between parkrun events and monitoring sites makes this difficult to prove decisively.
Conclusions: It has been determined that temperature and relative humidity can have the largest detrimental impact on parkrun performance, with ozone also being detrimental in some instances[JH(G+ESLF3] . The influence of other variables cannot be discounted however and it is recommended that modelling is performed to further determine the extent to which ‘at event’ meteorology and air quality has on performance. In the future, there results can be used to determine safe operating and exercise conditions for parkrun and other public athletics events.
Key Points
· Temperature and relative humidity have the largest detrimental impact on parkrun participants in the Greater London area.
· Air quality impacts are less clear but it is shown that ozone, as an irritant to the cardiorespiratory system, can lead to slower times.
· Modelling ‘at event’ air quality is recommended to improve data resolution and influence on participants.
... It is well known that weather conditions are likely to deteriorate and negatively impact marathon race performance (Martin, 2007). Different environmental factors such as temperature (Cheuvront and Haymes, 2001;Ely et al., 2007;Vihma, 2010;Knechtle et al., 2019;Nikolaidis et al., 2019b;Gasparetto and Nesseler, 2020), wind (Vihma, 2010;Knechtle et al., 2019;Nikolaidis et al., 2019b), rain Nikolaidis et al., 2019b), and humidity (Vihma, 2010;Knechtle et al., 2019;Nikolaidis et al., 2019b) are reported to have an influence on marathon running performance. ...
... Especially environmental temperatures seemed to have a high impact on marathon running performance (Ely et al., , 2008Vihma, 2010;El Helou et al., 2012;Knechtle et al., 2019;Gasparetto and Nesseler, 2020) where increasing air temperatures seemed to have the highest impact on marathon race times (Cheuvront and Haymes, 2001;Ely et al., 2007;Vihma, 2010;Gasparetto and Nesseler, 2020). ...
Aim: This study investigated the influence of weather conditions on running performance in female and male age group runners in the largest marathon in the world, the ‘New York City Marathon’. Methods: The analysis included data from 1,280,557 finishers the 'New York City Marathon' from the years 1970 to 2019. Linear mixed models for men and women finishers with race time (min) as dependent variable and 5-year age groups, temperature, wind and relative humidity tertiles (low, medium, high) as independent factors and finisher as random intercept was performed. Additional models with an interaction between age groups and one weather variable each were performed. Results: Temperature was positively associated with race time while windspeed and humidity were negatively associated (p<0.001). Men were significantly greater affected windspeed and humidity than women (p<0.001 for interaction) but not by temperature (p=0.17 for interaction). With an average of 8 min longer race time, high temperature had the greatest effect on race time. The effect of high humidity on race time was significantly increased in 40-59 years old men and 25-65 years old women. High temperatures had an increased effect on race time in 30-64 years old men and 40-64 years old women. The inverse association between race time and high windspeed was pronounced in finishers with younger age. Conclusion: Performance was lower on days with high temperature, low humidity and low windspeed. Men seemed to benefit more from higher humidity and windspeed than women. Aged (70+) finishers were not greater affected by high temperatures.
Keywords: running, elderly athlete, performance, environmental conditions, weather
... Secondly, unlike in cycling, the lower speed associated with running does not allow for excess heat dissipation via convection [19]. These factors can have a strong negative impact on running performance [20], particularly the marathon [21]. This negative impact is amplified (1) by a heavier body mass, which, at a given pace, requires more energy for running propulsion and therefore produces more heat, and (2) in heavier athletes running in a hot/humid environment by limiting heat exchange by convection and evaporation, who display greater imbalance between heat production and dissipation, even at slower paces [22]. ...
... Based on the analysis of winners' times in several marathons, Maughan [26] determined that the best running temperature is between 10 °C and 12 °C for elite athletes. Beyond this temperature, the analysis of 136 marathons performed between a wet-bulb globe temperature (WBGT) of 5 and 25 °C showed a decrease in performance with an increase in WBGT (Fig. 15.2; [21]). Interestingly, these authors also showed that slower runners, who are exposed to heat for a longer time than faster runners, are more affected by temperature. ...
Physical performance in a tropical environment, combining high heat and humidity, is a difficult physiological challenge that requires specific preparation. The elevated humidity of a tropical climate impairs the thermoregulatory mechanisms by limiting the rate of sweat evaporation. Hence, a proper management of whole-body temperature is required to complete an ultra-endurance event in such an environment. In these long-duration events, which can last from 8 to 20 h, held in hot and humid settings, performance is tightly linked to the ability in maintaining an optimal hydration status. Indeed, the rate of withdrawal in these longer races was associated with lower water intake, and the majority of finishers exhibited alterations in electrolyte balance (e.g., sodium). Hence, this work reviews the effects on performance of high heat and humidity in two representative ultra-endurance sports, ultramarathons and long-distance triathlons, and several countermeasures to counteract the impact of these harsh environmental stresses and maintain a high level of performance, such as hydration, cooling strategies and heat acclimation.
... 61). It is now apparent that endurance performance can progressively decline as ambient temperature increases beyond ~10°C (Galloway & Maughan 1997;Ely et al., 2007), although this relationship will be influenced by other parameters influencing heat exchange, including exercise mode (Junge et al., 2016) and other climatic factors (Maughan et al., 2012;Otani et al., 2018). Nevertheless, there remains a limited amount of research investigating the effects of HA on endurance performance in these temperate conditions. ...
... However, these thermal adaptations did not translate into a significant ergogenic effect. The environmental conditions in the present study approximated a Wet Bulb Globe Temperature (WBGT) of 18°C which has been reported to result in a 3.3% reduction in marathon running performance (Ely et al., 2007), although the impairment might be lessened with the shorter exposure-duration in the present study. Moreover, it has been argued that WBGT is not a good predictor of the effect of ambient conditions on exercise performance and that the integrated index is superior (Junge et al., 2016). ...
We investigated whether an 11-day heat acclimation programme (HA) enhanced endurance performance in a temperate environment, and the mechanisms underpinning any ergogenic effect. Twenty-four males (V̇O2max: 56.7±7.5 mL·kg⁻¹·min⁻¹) completed either: i) HA consisting of 11 consecutive daily exercise sessions (60-90 minutes·day⁻¹; n=16) in a hot environment (40°C, 50% RH) or; ii) duration and exertion matched exercise in cool conditions (CON; n=8 [11°C, 60% RH]). Before and after each programme power at lactate threshold, mechanical efficiency, VO2max, peak power output (PPO) and work done during a 30-minute cycle trial (T30) were determined under temperate conditions (22°C, 50% RH). HA reduced resting (-0.34±0.30°C) and exercising (-0.43±0.30°C) rectal temperature, and increased whole-body sweating (+0.37±0.31 L·hr⁻¹) (all P≤0.001), with no change in CON. Plasma volume increased in HA (10.1±7.2%, P<0.001) and CON (7.2±6.3%, P=0.015) with no between-groups difference, whereas exercise heart rate reduced in both groups, but to a greater extent in HA (-20±11 b·min⁻¹) than CON (-6±4 b·min⁻¹). VO2max, lactate threshold and mechanical efficiency were unaffected by HA. PPO increased in both groups (+14±18W), but this was not related to alterations in any of the performance or thermal variables, and T30 performance was unchanged in either group (HA: Pre=417±90 vs. Post=427±83 kJ; CON: Pre=418±63 vs. Post=423±56 kJ). In conclusion, 11-days HA induces thermophysiological adaptations, but does not alter the key determinants of endurance performance. In trained males, the effect of HA on endurance performance in temperate conditions is no greater than that elicited by exertion and duration matched exercise training in cool conditions.
... The advantage of this method is that the lap time and split time can be easily calculated when a target time is set. However, the runner's set pacing may be physiologically excessive due to various environmental factors such as weather conditions (temperature, humidity, rainfall, wind direction, and wind speed) (Ely et al., 2007;Porter, 1984;Vihma, 2010) and differences in elevation. ...
... The lowest race time temperature was 10.1°C at 9:00; the highest temperature was 15.7°C at 14:00. According to a previous study by Ely et al. (2007), changes in performance caused by such temperature differences Advance Publication by J-STAGE Published online October 26, 2020 ...
Heart rate (HR) monitoring, which reflects exercise intensity and environmental factors, is often used as the basis for pacing strategies in a marathon race. However, it is difficult to obtain appropriate feedback for only the HR value since cardiovascular drift (CV drift) occurs during prolonged exercise. Recently, cardiac cost (CC, which is HR divided by running velocity) has been shown to be a potential index for evaluating CV drift during a marathon race. The aim of this study was to clarify the relationship between CV drift and performance in a marathon race. Fourteen male university student runners participated. Each took part in incremental tests on a treadmill and subsequently ran a marathon. CV drift was evaluated using differences between CC in the 0-5 km segment of the race and every 5 km segment (ΔCC) thereafter. Marathon performance was examined from two viewpoints: absolute performance (average running velocity during the race, Vmar), and relative performance (Vmar against velocity corresponding to the ventilatory threshold, vVT achv). Significant correlations were found between ΔCC and vVT achv in the 25-30 km, 30-35 km and 35-40 km race segments (r = −0.672, −0.671 and −0.661, respectively), suggesting that excessive CV drift had a negative impact on relative performance. Based on our results, we conclude that suppression of CV drift after 25 km is an important factor for improving relative performance in a marathon race.
... In addition, VF build and VF tree were larger in the locations where WBGT was suppressed. Because Ely et al. showed that there is a progressive slowing of marathon performance as the WBGT increases from 5 to 25 • C [50], if WBGT can be suppressed by high VF build and VF tree , athletes' performance can be improved. Minimum WBGT for Sapporo is 21 • C for the 5:00 a.m. ...
A marathon is a grueling endurance race, and runners are at risk of heatstroke. Therefore, the thermal environment of the marathon course should be accurately assessed. Solar radiation, a factor in the thermal environment, is particularly affected by the surrounding environment. In this study, we proposed a method to calculate wet-bulb globe temperature (WBGT) in a short period of time using geographic information system (GIS) data, considering changes in solar radiation. WBGT is used as an indicator of heat stroke. This method was used to assess the risk of heat stroke due to weather conditions, span of time, and location on the marathon course of the Tokyo 2020 Olympics. According to the analysis results, in Sapporo, trees and buildings can suppress WBGT by about 2 °C, but on days when the average temperature exceeded 26 °C, WBGT exceeded 21 °C from 5:00 to 13:00. On the contrary, even in August, the hottest month of the year, there were days when WBGT was almost always below 21 °C from 5:00 to 13:00. In other words, it is concluded that the risk of heat stroke can be reduced if the marathon is held in accordance with the weather conditions of the day. In addition, by mapping and identifying locations where there is little change in attenuated WBGT, it is possible to identify locations where the thermal environment should be improved.
... Hot environmental conditions impair exercise performance by raising thermal and physiological strain (Ely et al. 2007;Mohr et al. 2012; Morante and Brotherhood 2008;Périard et al. 2014a;Racinais et al. 2015). Repeated exposure to heat stress (heat acclimation (HA)) can lessen this strain (Guy et al. 2015;Chalmers et al. 2014;Tyler et al. 2016), by inducing beneficial adaptations to the heat (Taylor 2014;Sawka et al. 2011). ...
Purpose
This study investigated the effects of acute hyperthermia and heat acclimation (HA) on maximal and rapid voluntary torque production, and their neuromuscular determinants.
Methods
Ten participants completed 10 days of isothermic HA (50 °C, 50% rh) and had their knee-extensor neuromuscular function assessed in normothermic and hyperthermic conditions, pre-, after 5 and after 10 days of HA. Electrically evoked twitch and octet (300 Hz) contractions were delivered at rest. Maximum voluntary torque (MVT), surface electromyography (EMG) normalised to maximal M-wave, and voluntary activation (VA) were assessed during brief maximal isometric voluntary contractions. Rate of torque development (RTD) and normalised EMG were measured during rapid voluntary contractions.
Results
Acute hyperthermia reduced neural drive (EMG at MVT and during rapid voluntary contractions; P < 0.05), increased evoked torques ( P < 0.05), and shortened contraction and relaxation rates ( P < 0.05). HA lowered resting rectal temperature and heart rate after 10 days ( P < 0.05), and increased sweating rate after 5 and 10 days ( P < 0.05), no differences were observed between 5 and 10 days. The hyperthermia-induced reduction in twitch half-relaxation was attenuated after 5 and 10 days of HA, but there were no other effects on neuromuscular function either in normothermic or hyperthermic conditions.
Conclusion
HA-induced favourable adaptations to the heat after 5 and 10 days of exposure, but there was no measurable benefit on voluntary neuromuscular function in normothermic or hyperthermic conditions. HA did reduce the hyperthermic-induced reduction in twitch half-relaxation time, which may benefit twitch force summation and thus help preserve voluntary torque in hot environmental conditions.
... These challenges will affect runners increasingly as the race progresses, and may contribute to higher rates of slowing in warmer environmental conditions [8]. Among competitive runners, warmer weather slows both men and women [9]. However, the fastest runners slow more during the second half, whereas others appear to adopt a slower pacing strategy from the outset [10]. ...
... In the future, I believe that the data of fitness platforms will be enriched with additional information. Both additional data from wearables (spatiotemporal, kinematic and kinetic) as well as context information about the run (weather, surface of running track based on GPS) will enable even more detailed insights into the biomechanics and physiology of endurance runners in specific conditions [231,232]. Especially longitudinal studies based on this kind of data will provide new insights into the response of runners to training or running-related injuries, which have not been possible before due to a lack of data [21]. ...
Body-worn sensors, so-called wearables, are getting more and more popular in the sports domain. Wearables offer real-time feedback to athletes on technique and performance, while researchers can generate insights into the biomechanics and sports physiology of the athletes in real-world sports environments outside of laboratories. One of the first sports disciplines, where many athletes have been using wearable devices, is endurance running. With the rising popularity of smartphones, smartwatches and inertial measurement units (IMUs), many runners started to track their performance and keep a digital training diary. Due to the high number of runners worldwide, which transferred their data of wearables to online fitness platforms, large databases were created, which enable Big Data analysis of running data. This kind of analysis offers the potential to conduct longitudinal sports science studies on a larger number of participants than ever before. In this dissertation, both studies showing how to extract endurance running-related parameters from raw data of foot-mounted IMUs as well as a Big Data study with running data from a fitness platform are presented.
... However, one reason that can explain these differences is the higher temperature observed in the 2018 edition. This higher environmental temperature could explain the faster relative speed in the first sections of the race 35,36 , and also a decrease in speed in the second half of the race due to thermal stress 35,37 . Further studies could explore the effect of environmental conditions on pacing in a controlled laboratory study. ...
Running pacing has become a focus of interest over recent years due to its relationship with performance, however, it is still unknown the consistency of each race in different editions. The aim of this study is to analyze the consistency of pacing profile in three consecutive editions of three marathon races. A database of 282,808 runners, compiled from three different races (Chicago, London, and Tokyo Marathon) and three editions (2017, 2018, and 2019) was analyzed. Participants were categorized according to their time performance in the marathon, every 30 min from 2:30 h to sub-6 h. The relative speed of each section for each runner was calculated as a percentage of the average speed for the entire race. The intraclass correlation coefficients (ICC) of relative speed at the different pacing section, taking into account the runner time categories, was excellent over the three marathon editions (ICC > 0.93). The artificial intelligence model showed an accuracy of 86.8% to classify the runners' data in three marathons, suggesting a consistency between editions with identifiable differences between races. In conclusion, although some differences have been observed between editions in certain sections and marathon runner categories, excellent consistency of the pacing profile was observed. The study of pacing profile in a specific marathon can, therefore, be helpful for runners, coaches and marathon organizers for planning the race and improving its organization.
... Additionally, exercise in the heat negatively impacts exercise performance and athlete safety [2]. For example, marathon performance progressively decreases as the Wet Bulb Globe Temperature (WBGT) increases from 5 • C to 25 • C [3]. Furthermore, exertional heat stroke is among the top three leading causes of death in sport, and other exertional heat illnesses, including heat exhaustion, heat syncope, and heat cramps, are prevalent and recurring illnesses across all levels of sport [4,5]. ...
The purpose of this study was to examine the changes in metabolic heat production (Hprod), evaporative heat loss (Hevap), and dry heat loss (Hdry), following heat acclimatization (HAz) and heat acclimation (HA). Twenty-two male endurance athletes (mean ± standard deviation; age, 37 ± 12 y; body mass, 73.4 ± 8.7 kg; height, 178.7 ± 6.8 cm; and VO2max, 57.1 ± 7.2 mL·kg−1·min−1) completed three trials (baseline; post-HAz; and post-HA), which consisted of 60 min steady state exercise at 59 ± 2% velocityVO2max in the heat (ambient temperature [Tamb], 35.2 ± 0.6 °C; relative humidity [%rh] 47.5 ± 0.4%). During the trial, VO2 and RER were collected to calculate Hprod, Hevap, and Hdry. Following the baseline trial, participants completed self-directed outdoor summer training followed by a post-HAz trial. Then, five days of HA were completed over eight days in the heat (Tamb, 38.7 ± 1.1 °C; %rh, 51.2 ± 2.3%). During the HA sessions, participants exercised to maintain hyperthermia (38.50 °C and 39.75 °C) for 60 min. Then, a post-HA trial was performed. There were no differences in Hprod between the baseline (459 ± 59 W·m−2), post-HAz (460 ± 61 W·m−2), and post-HA (464 ± 55 W·m−2, p = 0.866). However, Hevap was significantly increased post-HA (385 ± 84 W·m−2) compared to post-HAz (342 ± 86 W·m−2, p = 0.043) and the baseline (332 ± 77 W·m−2, p = 0.037). Additionally, Hdry was significantly lower at post-HAz (125 ± 8 W·m−2, p = 0.013) and post-HA (121 ± 10 W·m−2, p < 0.001) compared to the baseline (128 ± 7 W·m−2). Hdry at post-HA was also lower than post-HAz (p = 0.049). Hprod did not change following HAz and HA. While Hdry was decreased following HA, the decrease in Hdry was smaller than the increases in Hevap. Adaptations in body heat exchange can occur by HA following HAz.
... Lee et al. (2018) e Yoshino e Miyashita (2007) apontam existir um relacionamento entre sintomas apresentados pelo corpo humano e as condições climáticasàs quais as pessoas estão submetidas. Em contrapartida, Wachowicz et al. (2019), Vihma (2010), Ely et al. (2007) e El Helou et al. (2012 discutem o impacto das condições climáticas sobre o rendimento físico de atletas. Suas conclusões apontam que o desempenho físicó e afetado pelas condições climáticas, e a intensidade do impactoé diferente para cada pessoa. ...
A pandemia da COVID-19 tem demandado vários estudos sobre estratégias para combatê-la. Contudo, no que diz respeito à identificação de infectados, existe a possibilidade de pessoas apresentarem os sintomas sem estarem com a doença. Um dos fatores que influenciam na manifestação de sintomas, relacionados à COVID-19, são as condições climáticas. Neste trabalho, apresentamos uma arquitetura de suporte à decisão, que tem o objetivo de elucidar a influência das condições climáticas sobre os sintomas da COVID-19 e, com o apoio de videoconferências, auxiliar a colaboração para tomada de decisões no combate à pandemia. Desenvolver uma base de conhecimento, através de técnicas inteligentes, mostrou-se necessário para alcançar nosso objetivo.
... Environmental heat stress is known to impair aerobic exercise performance [1][2][3] in response to an increase in whole-body temperature and the consequent adjustments in cardiovascular, central nervous system and skeletal muscle function [4]. The rise in whole-body temperature is also associated with a greater risk of exertional heat illness in uncompensable conditions [5,6]. ...
Background
Physiological heat adaptations can be induced following various protocols that use either artificially controlled (i.e. acclimation) or naturally occurring (i.e. acclimatisation) environments. During the summer months in seasonal climates, adequate exposure to outdoor environmental heat stress should lead to transient seasonal heat acclimatisation.
Objectives
The aim of the systematic review was to assess the available literature and characterise seasonal heat acclimatisation during the summer months and identify key factors that influence the magnitude of adaptation.
Eligibility Criteria
English language, full-text articles that assessed seasonal heat acclimatisation on the same sample of healthy adults a minimum of 3 months apart were included.
Data Sources
Studies were identified using first- and second-order search terms in the databases MEDLINE, SPORTDiscus, CINAHL Plus with Full Text, Scopus and Cochrane, with the last search taking place on 15 July 2021.
Risk of Bias
Studies were independently assessed by two authors for the risk of bias using a modified version of the McMaster critical review form.
Data Extraction
Data for the following outcome variables were extracted: participant age, sex, body mass, height, body fat percentage, maximal oxygen uptake, time spent exercising outdoors (i.e. intensity, duration, environmental conditions), heat response test (i.e. protocol, time between tests), core temperature, skin temperature, heart rate, whole-body sweat loss, whole-body and local sweat rate, sweat sodium concentration, skin blood flow and plasma volume changes.
Results
Twenty-nine studies were included in this systematic review, including 561 participants across eight countries with a mean summer daytime wet-bulb globe temperature (WBGT) of 24.9 °C (range: 19.5–29.8 °C). Two studies reported a reduction in resting core temperature (0.16 °C; p < 0.05), 11 reported an increased sweat rate (range: 0.03–0.53 L·h⁻¹; p < 0.05), two observed a reduced heart rate during a heat response test (range: 3–8 beats·min⁻¹; p < 0.05), and six noted a reduced sweat sodium concentration (range: − 22 to − 59%; p < 0.05) following summer. The adaptations were associated with a mean summer WBGT of 25.2 °C (range: 19.6–28.7 °C).
Limitations
The available studies primarily focussed on healthy male adults and demonstrated large differences in the reporting of factors that influence the development of seasonal heat acclimatisation, namely, exposure time and duration, exercise task and environmental conditions.
Conclusions
Seasonal heat acclimatisation is induced across various climates in healthy adults. The magnitude of adaptation is dependent on a combination of environmental and physical activity characteristics. Providing environmental conditions are conducive to adaptation, the duration and intensity of outdoor physical activity, along with the timing of exposures, can influence seasonal heat acclimatisation. Future research should ensure the documentation of these factors to allow for a better characterisation of seasonal heat acclimatisation.
PROSPERO Registration
CRD42020201883.
... www.nature.com/scientificreports/ marathon runners including elite athletes 14,15 , and since the WBGT standards suggested by the International Institute for Running Medicine (IIRM) 16 and American College of Sports Medicine (ACSM) 17 are referred to in the management of various marathons, we adopt the WBGT as an indicator of the feasibility of hosting an Olympic marathon. We utilize the seven GCMs included in the S14 retrospective meteorological forcing dataset (S14FD) 18 , which was developed based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) 19 . ...
There are concerns about the impact of climate change on Olympic Games, especially endurance events, such as marathons. In recent competitions, many marathon runners dropped out of their races due to extreme heat, and it is expected that more areas will be unable to host the Games due to climate change. Here, we show the feasibility of the Olympic marathon considering the variations in climate factors, socioeconomic conditions, and adaptation measures. The number of current possible host cities will decline by up to 27% worldwide by the late twenty-first century. Dozens of emerging cities, especially in Asia, will not be capable of hosting the marathon under the highest emission scenario. Moving the marathon from August to October and holding the Games in multiple cities in the country are effective measures, and they should be considered if we are to maintain the regional diversity of the Games.
... It has also been suggested that performance was less affected by warm weather in females than in males during a 161-km ultra-marathon [180], although no sex difference was found in marathons. The opposite may actually be true since performance is more negatively affected for slower populations of runners on that distance [181]. Importantly, because of their smaller body size, lower heat generation, and less sweat loss (i.e. ...
In recent years, there has been a significant expansion in female participation in endurance (road and trail) running. The often reported sex differences in maximal oxygen uptake (VO2max) are not the only differences between sexes during prolonged running. The aim of this narrative review was thus to discuss sex differences in running biomechanics, economy (both in fatigue and non-fatigue conditions), substrate utilization, muscle tissue characteristics (including ultrastructural muscle damage), neuromuscular fatigue, thermoregulation and pacing strategies. Although males and females do not differ in terms of running economy or endurance (i.e. percentage VO2max sustained), sex-specificities exist in running biomechanics (e.g. females have greater non-sagittal hip and knee joint motion compared to males) that can be partly explained by anatomical (e.g. wider pelvis, larger femur-tibia angle, shorter lower limb length relative to total height in females) differences. Compared to males, females also show greater proportional area of type I fibres, are more able to use fatty acids and preserve carbohydrates during prolonged exercise, demonstrate a more even pacing strategy and less fatigue following endurance running exercise. These differences confer an advantage to females in ultra-endurance performance, but other factors (e.g. lower O2 carrying capacity, greater body fat percentage) counterbalance these potential advantages, making females outperforming males a rare exception. The present literature review also highlights the lack of sex comparison in studies investigating running biomechanics in fatigue conditions and during the recovery process.
... Increased air temperature, particularly >25°C, appears detrimental to running performance in elite middle-and long-distance endurance events [1]. The magnitude of performance decrement is proportional to both the event duration and the temperature difference versus purported optimal conditions for endurance performance of ~10-15°C [2]. Increased atmospheric water vapor (i.e. ...
This study investigated the effect of heat stress on locomotor activity within international field hockey at team, positional and playing-quarter levels. Analysis was conducted on 71 matches played by the Malaysia national men’s team against 24 opponents. Fixtures were assigned to match conditions, based on air temperature [COOL (14 ± 3°C), WARM (24 ± 1°C), HOT (27 ± 1°C), or VHOT (32 ± 2°C), p < 0.001]. Relationships between locomotor metrics and air temperature (AIR), absolute and relative humidity, and wet bulb globe temperature (WBGT) were investigated further using correlation and regression analyses. Increased AIR and WBGT revealed similar correlations (p < 0.01) with intensity metrics; high-speed running (AIR r = −0.51, WBGT r = −0.45), average speed (AIR r = −0.48, WBGT r = −0.46), decelerations (AIR r = −0.41, WBGT r = −0.41), sprinting efforts (AIR r = −0.40, WBGT r = −0.36), and sprinting distance (AIR r = −0.37, WBGT r = −0.29). In comparison to COOL, HOT, and VHOT matches demonstrated reduced high-speed running intensity (−14–17%; p < 0.001), average speed (−5-6%; p < 0.001), sprinting efforts (−17%; p = 0.010) and decelerations per min (−12%; p = 0.008). Interactions were found between match conditions and playing quarter for average speed (+4-7%; p = 0.002) and sprinting distance (+16-36%; p < 0.001), both of which were higher in the fourth quarter in COOL versus WARM, HOT and VHOT. There was an interaction for “low-speed” (p < 0.001), but not for “high-speed” running (p = 0.076) demonstrating the modulating effect of air temperature (particularly >25°C) on pacing within international hockey. These are the data demonstrating the effect of air temperature on locomotor activity within international men’s hockey, notably that increased air temperature impairs high-intensity activities by 5–15%. Higher air temperatures compromise high-speed running distances between matches in hockey.
... It is commonly accepted today that performance in endurance and intermittent sports is impaired in an environment where endogenous heat production exceeds the body's Life 2021, 11, 1326 2 of 16 thermoregulatory capacity [13,14] because the alteration of thermal homeostasis leads to the development of compensatory mechanisms that impair performance. ...
The practice of physical activity in a variable climate during the same competition is becoming more and more common due to climate change and increasingly frequent climate disturbances. The main aim of this pilot study was to understand the impact of cold ambient temperature on performance factors during a professional cycling race. Six professional athletes (age = 27 ± 2.7 years; height = 180.86 ± 5.81 cm; weight = 74.09 ± 9.11 kg; % fat mass = 8.01 ± 2.47%; maximum aerobic power (MAP) = 473 ± 26.28 W, undertook ~20 h training each week at the time of the study) participated in the Tour de la Provence under cold environmental conditions (the ambient temperature was 15.6 ± 1.4 °C with a relative humidity of 41 ± 8.5% and the normalized ambient temperature (Tawc) was 7.77 ± 2.04 °C). Body core temperature (Tco) was measured with an ingestible capsule. Heart rate (HR), power, speed, cadence and the elevation gradient were read from the cyclists’ onboard performance monitors. The interaction (multivariate analysis of variance) of the Tawc and the elevation gradient has a significant impact (F(1.5) = 32.2; p < 0.001) on the variables (cadence, power, velocity, core temperature, heart rate) and on each individual. Thus, this pilot study shows that in cold environmental conditions, the athlete’s performance was limited by weather parameters (ambient temperature associated with air velocity) and race characteristics. The interaction of Tawc and elevation gradient significantly influences thermal (Tco), physiological (HR) and performance (power, speed and cadence) factors. Therefore, it is advisable to develop warm-up, hydration and clothing strategies for competitive cycling under cold ambient conditions and to acclimatize to the cold by training in the same conditions to those that may be encountered in competition.
... Several studies shown heat as an important factor that limits exercise performance (Ely et al., 2007;Mohr et al., 2012;No & Kwak, 2016;Donnan et al., 2021). Tatterson et al. (2000) indicated that the exercise performance of elite cyclists is affected by heat stress. ...
Problem Statement: Numerous studies have been conducted to improve athletic performance, which is affected by various factors. However, studies on the exercise performance of heat-adapted athletes under different environmental condition is still limited. Approach: Twelve male recreational athletes took part in the present study. The participants underwent prolonged running at the intensity of 70% of their respective VO 2max for 60 min. It was then immediately followed by a 20-minutes time-trial performance in a randomized, cross-over trial either in the heat (32°C, 70% relative humidity) or thermoneutral (25°C, 70% relative humidity) environments. The nude body weights of the participants were measured before and after the trials. The participants' blood samples were obtained before warm-up, at the beginning of exercise, at each 20 minutes and 24 hours after exercise. These samples were examined for changes in plasma volume, plasma lactate and creatine kinase activity. Purpose: This study investigated the effects of prolonged exercise in a hot or thermoneutral environments on different physiological parameters and time-trial performance in recreational athletes. Results: There were no differences between the trials in terms of body weight, plasma lactate, or creatine kinase activity. However, as compared to a thermoneutral environment, the athletes' plasma volume changes and sweat rate were significantly (p < 0.05) higher in the heat trial. The thermoneutral and heat trials had running distances of 3.44 ± 0.5 and 3.13 ± 0.5 km, respectively. Conclusion: These findings suggest that running in the heat has no effect on plasma lactate levels or muscle damage. However, the participants' running performance was hampered by the hot and humid conditions.
... When examining other factors which might improve endurance performance in the cold, acclimation is a viable approach to improved performance and has been reviewed elsewhere extensively [57,58]. Specific instances where acclimation may improve endurance performance would be marathon running where sudden inclement weather such as rain [59] affects running performance relative to optimal marathon conditions [60]. In addition, multi-day ski traverses in polar regions of the world have shown to be a "living lab", where prolonged exposure to extreme cold alters performance and physiological tolerance to cold weather [58,61]. ...
Although not a barrier to perform sport, cold weather environments (low ambient temperature, high wind speeds, and increased precipitation, i.e., rain/water/snow) may influence sport performance. Despite the obvious requirement for practical recommendations and guidelines to better facilitate training and competition in such cold environments, the current scientific evidence-base is lacking. Nonetheless, this review summarizes the current available knowledge specifically related to the physiological impact of cold exposure, in an attempt to provide practitioners and coaches alike with practical recommendations to minimize any potential negative performance effects, mitigate health issues, and best optimize athlete preparation across various sporting disciplines. Herein, the review is split into sections which explore some of the key physiological effects of cold exposure on performance (i.e., endurance exercise capacity and explosive athletic power), potential health issues (short-term and long-term), and what is currently known with regard to best preparation or mitigation strategies considered to negate the potential negative effects of cold on performance. Specific focus is given to “winter” sports that are usually completed in cold environments and practical recommendations for physical preparation.
... Individuals performing prolonged exercise in hot ambient conditions experience a progressive increase in thermal strain (i.e., core and skin temperature) which coincides with impaired endurance capacity and performance (1)(2)(3)(4)(5). Galloway and Maughan (6) were among the first to systematically evaluate the effect of manipulating dry-bulb temperature on exercise capacity and reported that relative to 11 C, time to exhaustion decreased by 13% in 4 C and 21 C, and by 45% in 31 C when exercising at 70% of maximal oxygen uptake (V _ O 2max ). ...
The effects of dry-bulb temperature on self-paced exercise performance, along with thermal, cardiovascular and perceptual responses, were investigated by minimizing differences in the skin-to-air vapor pressure gradient (P sk,sat -P a ) between temperatures. Fourteen trained male cyclists performed 30-km time trials in 13˚C and 44% relative humidity (RH), 20˚C and 70% RH, 28˚C and 78% RH, and 36˚C and 72% RH. Power output was similar in 13˚C (275±31 W; mean and SD) and 20˚C (272±28 W; P=1.00), lower in 36˚C (228±36 W) than 13˚C, 20˚C and 28˚C (262±27 W; P<0.001) and lower in 28˚C than 13˚C and 20˚C (P<0.001). Peak rectal temperature was higher in 36˚C (39.6±0.4˚C) than all conditions (P<0.001) and higher in 28˚C (39.1±0.4˚C) than 13˚C (38.7±0.3˚C; P<0.001) and 20˚C (38.8˚C±0.3˚C; P<0.01). Heart rate was higher in 36˚C (163±14 beats·min ⁻¹ ) than all conditions (P<0.001) and higher in 20˚C (156±11 beats·min ⁻¹ ; P=0.009) and 28˚C (159±11 beats·min ⁻¹ ; P<0.001) than 13˚C (153±11 beats·min ⁻¹ ). Cardiac output was lower in 36˚C (16.8±2.5 l·min ⁻¹ ) than all conditions (P<0.001) and lower in 28˚C (18.6±1.6 l·min ⁻¹ ) than 20˚C (19.4±2.0 l·min ⁻¹ ; P=0.004). Ratings of perceived exertion were higher in 36˚C than all conditions (P<0.001) and higher in 28˚C than 20˚C (P<0.04). Self-paced exercise performance was maintained in 13˚C and 20˚C at a matched evaporative potential, impaired in 28˚C and further compromised in 36˚C in association with a moderately lower evaporative potential and marked elevations in thermal, cardiovascular and perceptual strain.
... Previous laboratorybased studies have demonstrated reduced endurance of the exercise, measured by exercise time to exhaustion, under thermal stress [10,24]. In addition, thermal stress contributes to reduced marathon running performance, and a previous study suggested that marathon records deteriorated by 2-3% when wet-bulb globe temperature exceeded 20 • C [25,26]. Exercise under thermal stress induces fatigue and reduces exercise performance via several physiological and metabolic factors, including cardiorespiratory function, fluid balance, central nervous system function, and motor drive [14]. ...
We investigated the effects of acute thermal stress (30 ◦C and 40 ◦C) and ordinary temperature (20 ◦C) on cardiorespiratory function, skeletal muscle oxygenation, and exercise performance in healthy men. Eleven healthy males (21.5 ± 2.3 years) performed a graded exercise test (GXT) using a cycle ergometer in each environmental condition (20 ◦C, 30 ◦C, and 40 ◦C) in a random order with an interval of 1 week between each test. Before the test, they were allowed to rest for 30 min in a given environmental condition. All dependent variables (body temperature, cardiorespiratory function parameters, skeletal muscle oxygenation profiles, and exercise performance) were measured at rest and during GXT. GXT was started at 50 W and increased by 25 W every 2 min until subjects were exhausted. Body temperature increased proportionally at rest and at the end of exercise as thermal stress increased. There were no differences in the rating of perceived exertion, oxygen uptake, respiratory exchange ratio, and carbon dioxide excretion between environmental conditions. Heart rate (HR), minute ventilation (VE), and blood lactate levels were significantly higher at 30 ◦C and 40 ◦C than at 20 ◦C, and oxygen pulse was significantly lower at 40 ◦C than at 20 ◦C at various exercise loads. None of the skeletal muscle oxygenation profiles showed significant changes at rest or during exercise. Maximal oxygen uptake, peak power, and exercise time significantly decreased proportionally as thermal stress increased, and this decrease was most pronounced at 40 ◦C. Acute thermal stress induces a decrease in exercise performance via increased body temperature, HR, VE, and blood lactate levels and decreased oxygen pulse during load-homogenized exercise. This phenomenon was more prominent at 40 ◦C than at 30 ◦C and 20 ◦C.
... Unfortunately, information on the direct effects of air pollution on exercise performance are scarce or coming from laboratory settings. Most researches conducted on the topic during sport events, have investigated air pollution effect on marathon running 98,99 . These events last more than 2 hours and such prolonged duration prevents from measuring a clear, isolated effect of pollutants on running performance, because of the confounding effect of other environmental variables (i.e. ...
Olympic sports represent, through their athletes, an iconic source of inspiration and ambition for everyone. Every Olympiad we are reminded of the astonishing achievements that can be reached through hard work and dedication. Nevertheless, these performances are very far from the reality of those being physically active to improve their health and fitness. The technological development that humanity has gone through in the last couple of centuries, has engineered physical activity out of our lives and dramatically altered our lifestyle, leading to the development of diseases that were not so prevalent. Exercise has become an integral part of our lives and it is now regarded as a medicine to prevent and counteract chronic conditions that are associated with a sedentary lifestyle. In this context Olympic sports can play a key role in attracting people to be physically active as well as leveraging on city governments to allow, not only sport participation, but a global active lifestyle. International Sports Federations (ISF) have therefore a central position in ensuring sports are in line with the changes occurring in society as well as fostering its natural evolution. Examples of this evolution are gender equality and sustainability, topics that finally are becoming central in ISFs as they have been in society for decades. Therefore, Olympic sports should acknowledge the prominent role they have in society and contribute to its further development by promoting socially relevant actions.
... These mechanisms, already impaired in a hot environment, are further altered in humid climate, which drastically limits evapotranspiration due to the water-saturated atmosphere [3]. Hence, running may be the sport most impacted by a tropical climate because heat dissipation by circulating air convection around the body, such as in cycling, is reduced [4]. To limit its effect in endurance sports and to enhance thermoregulatory processes, several countermeasures have been studied with various outcomes on performance: acclimation, hydration, pacing, and cooling strategies [1]. ...
Aerobic performance is negatively impacted by tropical climate due to impairment of thermoregulatory mechanisms. We tested the hypothesis that a torso application of a 4% menthol solution would have the same effect on a best performance 10-km run as an external use of cold water. Thirteen trained male athletes completed four outdoor 10-km runs (T=29.0±1.3°C, relative humidity 59.0±13.6%) wearing a tee-shirt soaked every 2-km either in a cold (~6°C) or warm/ambient (~28°C) solution, consisting in water or in a 4% menthol solution, (CTL, MENT-Amb, CLD and MENT-CLD). Run performances were improved from 4.8 to 6.1% in CLD (51.4±5.5 min), MENT-Amb (52.2±5.9 min) and MENT-CLD (51.4±5.1 min) conditions (vs. CTL, 55.4±8.4 min, P<0.05), without differences between these three conditions, whereas heart rate (177±13bpm), body temperature (38.7±0.6°C) and drink ingestion (356±170 g) were not modified. Thermal sensation after running was lower in MENT-CLD (vs. CTL, P<0.01) and thermal acceptability was higher in CLD and MENT-Amb (vs. CTL, P<0.05), but thermal comfort, feeling scale and rate of perceived exertion remained unchanged. The use of menthol on skin enhances aerobic performance in a tropical climate, and no differences in performance were observed between menthol and traditional percooling strategies. However, combining both menthol and traditional percooling brought no further improvements.
... The comparison with the Worlds Athletics Championships study must however be made with caution because this study included track and field athletes for which heat acclimatization is less important [6]. Considering the repercussions of heat stress on endurance performance [14,31,32], and given the fact that heat acclimatization can reduce the likelihood of heat illness [20], one may wonder why so few runners in our study acclimatized before the event. We suggest two possible explanations for this. ...
The aim of this study was to assess the history of exertional heat illness (EHI), heat preparation, cooling strategies, heat related symptoms, and hydration during an ultra-endurance running event in a warm and humid environment. This survey-based study was open to all people who participated in one of the three ultra-endurance races of the Grand Raid de la Réunion. Ambient temperature and relative humidity were 18.6 ± 5.7 °C (max = 29.7 °C) and 74 ± 17%, respectively. A total of 3317 runners (56% of the total eligible population) participated in the study. Overall, 78% of the runners declared a history of heat-related symptoms while training or competing, and 1.9% reported a previous diagnosis of EHI. Only 24.3% of study participants living in temperate climates declared having trained in the heat before the races, and 45.1% of all respondents reported a cooling strategy during the races. Three quarter of all participants declared a hydration strategy. The planned hydration volume was 663 ± 240 mL/h. Fifty-nine percent of the runners had enriched their food or drink with sodium during the race. The present study shows that ultra-endurance runners have a wide variability of hydration and heat preparation strategies. Understandings of heat stress repercussions in ultra-endurance running need to be improved by specific field research.
... The high sensitivity of our model allows for a more accurate quantification of PWC with the more subtle climatic alterations observed in temperate climates, rather than the exclusive consideration of more severe conditions. Importantly, it is well established that 25°C WBGT already far exceeds optimal ambient conditions for human physical performance (Ely et al. 2007;Galloway and Maughan 1997;Taylor et al. 1963). In contrast, our reference condition (15°C;12°C WBGT) represents a more optimal environment for human physical work output (Taylor et al. 1963), allowing us to document PWC reductions in environments as mild as 18°C WBGT. ...
Occupational heat stress directly hampers physical work capacity (PWC), with large economic consequences for industries and regions vulnerable to global warming. Accurately quantifying PWC is essential for forecasting impacts of different climate change scenarios, but the current state of knowledge is limited, leading to potential underestimations in mild heat, and overestimations in extreme heat. We therefore developed advanced empirical equations for PWC based on 338 work sessions in climatic chambers (low air movement, no solar radiation) spanning mild to extreme heat stress. Equations for PWC are available based on air temperature and humidity, for a suite of heat stress assessment metrics, and mean skin temperature. Our models are highly sensitive to mild heat and to our knowledge are the first to include empirical data across the full range of warm and hot environments possible with future climate change across the world. Using wet bulb globe temperature (WBGT) as an example, we noted 10% reductions in PWC at mild heat stress (WBGT = 18°C) and reductions of 78% in the most extreme conditions (WBGT = 40°C). Of the different heat stress indices available, the heat index was the best predictor of group level PWC (R2 = 0.96) but can only be applied in shaded conditions. The skin temperature, but not internal/core temperature, was a strong predictor of PWC (R2 = 0.88), thermal sensation (R2 = 0.84), and thermal comfort (R2 = 0.73). The models presented apply to occupational workloads and can be used in climate projection models to predict economic and social consequences of climate change.
... In contrast, it should be noted that the London marathon studied recorded historically high environmental temperatures. This could also have caused a decrease in speed in the second half of the race due to thermal stress (Ely, Cheuvront, Roberts, & Montain, 2007;Trubee et al., 2014), also resulting in higher relative speed values being observed in the first sections of the race. Runners and coaches should take into account the environmental conditions of the race to develop strategies (e.g. ...
This study aimed to analyse differences in pacing profiles in four marathon competitions and to explore that pacing per time category. A database of 91,493 runners gathered from 4 different races was analysed (Valencia, Chicago, London and Tokyo Marathon). Participants were categorized in accordance with their completion time. The relative speed of each section for each runner was calculated as a percentage of the average speed for the entire race. In the four marathons studied, the first 5 km differed widely, presenting London the highest relative speeds (5 km: CI95% London vs. Valencia [12.1, 13.6%], p < 0.001 and ES = 2.1; London vs. Chicago [5.5, 7.1%], p < 0.001 and ES = 1.1; London vs. Tokyo [15.2, 16.8%], p < 0.001 and ES = 2.3). Races did not differ at each section for high-performance runners (sub-2:30), but differences between races increased as the time category increases (e.g. 35 km and sub-3:00: CI95% London vs. Tokyo [-3.1, -1.8%], p < 0.001 and ES = 0.7; 35 km and sub-5:00: London vs. Tokyo [-9.8, -9.2%], p < 0.001 and ES = 1.3). The difference in relative speed between the first and second half of the marathon was higher in London than in the other marathons (e.g. CI95% London vs. Valencia [10.3, 10.8%], p < 0.001 and ES = 1.3). In conclusion, although race characteristics affect pacing, this effect was higher as the category time increases. Race pacing characteristics should be taken into consideration for runners and coaches choosing the race and working on pacing strategies, for researches to extrapolate or interpret results, or for race organizations to improve its pacing characteristics.
... Endurance performance is impaired in high ambient temperatures [196,197], by a combination of factors including elevated core and skin temperature [172,189], reduced central blood volume [46,54,55,65,198], systemic low-grade inflammation [42,177] and perceptual responses to heat [96]. Physiological changes that improve heat dissipation mechanisms enable endurance performance in the heat to be improved following HA [125,199]. ...
Acute exposure to heat, such as that experienced by people arriving into a hotter or more humid environment, can compromise physical and cognitive performance as well as health. In military contexts heat stress is exacerbated by the combination of protective clothing, carried loads, and unique activity profiles, making them susceptible to heat illnesses. As the operational environment is dynamic and unpredictable, strategies to minimize the effects of heat should be planned and conducted prior to deployment. This review explores how heat acclimation (HA) prior to deployment may attenuate the effects of heat by initiating physiological and behavioural adaptations to more efficiently and effectively protect thermal homeostasis, thereby improving performance and reducing heat illness risk. HA usually requires access to heat chamber facilities and takes weeks to conduct, which can often make it impractical and infeasible, especially if there are other training requirements and expectations. Recent research in athletic populations has produced protocols that are more feasible and accessible by reducing the time taken to induce adaptations, as well as exploring new methods such as passive HA. These protocols use shorter HA periods or minimise additional training requirements respectively, while still invoking key physiological adaptations, such as lowered core temperature, reduced heart rate and increased sweat rate at a given intensity. For deployments of special units at short notice (< 1 day) it might be optimal to use heat re-acclimation to maintain an elevated baseline of heat tolerance for long periods in anticipation of such an event. Methods practical for military groups are yet to be fully understood, therefore further investigation into the effectiveness of HA methods is required to establish the most effective and feasible approach to implement them within military groups.
... In general, increased heat exposure contributes to the development of thermoregulatory strain and weakened performance (known as hyperthermia-induced fatigue) [3]. For example, in marathon runners, an ambient temperature increase from 10 to 22°C causes competitors to slow anywhere from 2 to 10%, dependent upon on an individual's level of conditioning [4]. In non-human endotherms, experimental exposure to high ambient temperatures reduces flight time in birds [5,6] and running duration in mammals [7,8]. ...
In many vertebrates, parental care can require long bouts of daily exercise that can span several weeks. Exercise, especially in the heat, raises body temperature, and can lead to hyperthermia. Typical strategies for regulating body temperature during endurance exercise include modifying performance to avoid hyperthermia (anticipatory regulation) and allowing body temperature to rise above normothermic levels for brief periods of time (facultative hyperthermia). Facultative hyperthermia is commonly employed by desert birds to economize on water, but this strategy may also be important for chick-rearing birds to avoid reducing offspring provisioning when thermoregulatory demands are high. In this study, we tested how chick-rearing birds balance their own body temperature against the need to provision dependent offspring. We experimentally increased the heat dissipation capacity of breeding female tree swallows (Tachycineta bicolor) by trimming their ventral feathers and remotely monitored provisioning rates, body temperature and the probability of hyperthermia. Birds with an experimentally increased capacity to dissipate heat (i.e. trimmed treatment) maintained higher feeding rates than controls at high ambient temperatures (greater than or equal to 25°C), while maintaining lower body temperatures. However, at the highest temperatures (greater than or equal to 25°C), trimmed individuals became hyperthermic. These results provide evidence that chick-rearing tree swallows use both anticipatory regulation and facultative hyperthermia during endurance performance. With rising global temperatures, individuals may need to increase their frequency of facultative hyperthermia to maintain nestling provisioning, and thereby maximize reproductive success.
... A top runner shows an increase in body temperature due to energetic metabolism and a loss of body mass greater than a slower athlete [80,84]. This fact is confirmed by several authors [85,86,87] who indicate that running technique together with previous experience barely lead a top runner to a dehydration condition. Hofmann, Taylor and colleagues [80,84] have recorded a body mass loss up to 9% in some athletes, although not representing a dehydration status. ...
This review aims to investigate the physiological mechanisms that underlie the hydro-electrolyte balance of the human body and the most appropriate hydration modalities for individuals involved in physical and sports activities, with a focus on ultra-endurance events. The role of effective hydration in achieving optimal sports performance is also investigated. An adequate pre-hydration is essential to perform physical and sporting activity in a condition of eu-hydration and to mantain physiologic levels of plasma electrolyte. To achieve these goals, athletes need to consume adequate drinks together with consuming meals and fluids, in order to provide an adequate absorption of the ingested fluids and the expulsion of those in excess through diuresis. Therefore, there are important differences between individuals in terms of sweating rates, the amount of electrolytes loss and the specific request of the discipline practiced and the sporting event to pursue.
Objective:
The aim of the study was to evaluate the effect of a hot environment on several physiological variables of soccer players and suggest feasible solutions to it.
Subjects and methods:
The study is of prospective design, considering 66 participants comprising professional soccer players. All the participants completed the Physical Activity Readiness Questionnaire (PARQ). The participants were assigned to 3 different groups. Each group was assigned 22 participants. They were made to play in three different chambers, maintained at cool, moderate and hot temperatures. Players were made to play and various variables were determined to assess the effect of hot temperature on them.
Results:
Several variables were determined including absolute and relative oxygen uptake, heart rate, minute ventilation, the blood concentration of lactate and time to get exhausted. All the variables of players who played in hot temperatures have revealed higher heart rate, ventilation and increased lactate concentration. Players in a hot environment ran out faster.
Conclusions:
The study was concluded due to the players' dehydration and physiological deteriorated factors in a hot environment, leading to poor performances and also affecting the players' health in the long run. Further, the study suggested improving the environment around the game venues.
The short- and long-term impacts of air pollution on human health are well documented and include cardiovascular, neurological, immune system and developmental damage. Additionally, the irritant qualities of air pollutants can cause respiratory and cardiovascular distress. This can be heightened during exercise and especially so for those with respiratory conditions such as asthma. Meteorological conditions have also been shown to adversely impact athletic performance; but research has mostly examined the impact of pollution and meteorology on marathon times or running under laboratory settings. This study focuses on the half marathon distance (13.1 miles/21.1 km) and utilises the Great North Run held in Newcastle-upon-Tyne, England, between 2006 and 2019. Local meteorological (temperature, relative humidity, heat index and wind speed) and air quality (ozone, nitrogen dioxide and PM2.5) data is used in conjunction with finishing times of the quickest and slowest amateur participants, along with the elite field, to determine the extent to which each group is influenced in real-world conditions. Results show that increased temperatures, heat index and ozone concentrations are significantly detrimental to amateur half marathon performances. The elite field meanwhile is influenced by higher ozone concentrations. It is thought that the increased exposure time to the environmental conditions contributes to this greater decrease in performance for the slowest participants. For elite athletes that are performing closer to their maximal capacity (VO2 max), the higher ozone concentrations likely results in respiratory irritation and decreased performance. Nitrogen dioxide and PM2.5 pollution showed no significant relationship with finishing times. These results provide additional insight into the environmental effects on exercise, which is particularly important under the increasing effects climate change and regional air pollution. This study can be used to inform event organisation and start times for both mass participation and major elite events with the aim to reduce heat- and pollution-related incidents.
Background: The two aspects of the influence of environmental conditions on marathon running performance and pacing during a marathon have been separately and widely investigated. The influence of environmental conditions on the pacing of age group marathoners has, however, not been considered yet.
Objective: The aim of the present study was to investigate the association between environmental conditions (i.e., temperature, barometric pressure, humidity, precipitation, sunshine, and cloud cover), gender and pacing of age group marathoners in the “New York City Marathon”.
Methodology: Between 1999 and 2019, a total of 830,255 finishes (526,500 males and 303,755 females) were recorded. Time-adjusted averages of weather conditions for temperature, barometric pressure, humidity, and sunshine duration during the race were correlated with running speed in 5 km-intervals for age group runners in 10 years-intervals.
Results: The running speed decreased with increasing temperatures in athletes of age groups 20–59 with a pronounced negative effect for men aged 30–64 years and women aged 40–64 years. Higher levels of humidity were associated with faster running speeds for both sexes. Sunshine duration and barometric pressure showed no association with running speed.
Conclusion: In summary, temperature and humidity affect pacing in age group marathoners differently. Specifically, increasing temperature slowed down runners of both sexes aged between 20 and 59 years, whereas increasing humidity slowed down runners of <20 and >80 years old.
Purpose:
The Doha 2019 women's World Championship marathon took place in extreme hot (32 °C), humid conditions (74% relative humidity) culminating in unprecedented (41%) failure rates. We explored whether extreme heat or suboptimal pacing was responsible for diminished performance against a temperate "control" (London 2017: 19 °C, 59% relative humidity) and whether physical characteristics (eg, body surface area, estimated maximal oxygen uptake, habitual heat exposure) explained performance.
Method:
Five-kilometer-pace (km·h-1) data underwent repeated-measures analyses of hot (Doha, n = 40) versus temperate pacing and performance (London, n = 78) within and between marathon pacing (finisher quartiles normalized against personal best; n = 10 per group) and within hot marathon finishers versus nonfinishers (up to 10 km; normalized data). Possible predictors (multiple regression) of hot marathon pacing were explored. Tests to .05 alpha level, partial eta squared (ηp2) indicates effect size.
Results:
Mean (SD) of Doha (14.82 [0.96] km·h-1) pace was slower (London: 15.74 [0.96] km·h-1; P = .00; ηp2=.500). In hot conditions, athletes finishing in positions 1 to 10 (group 1) started more conservatively (93.7% [2.1%] of personal best) than slower runners (groups 3 and 4; 96.6% [2.8%] of personal best; P < .05, ηp2=.303). Groups were not different at 15 km and then slowed immediately (groups 3 and 4) or after 20 km (group 2). Finishers and nonfinishers adopted similar pace up to 10 km (P > .05, ηp2=.003). World ranking predicted (P = .00; r2 = .248) average pace in Doha.
Conclusion:
Extreme hot conditions reduced performance. Top 10 athletes adopted a conservative initial pace, whereas lower-placing athletes adopted a faster, aggressive start. Pacing alone does not explain high failure rates in nonfinishers. Athletes competing in the heat should initially pace conservatively to optimize performance.
Purpose
To determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions.
Methods
From 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (T core ; ingestible pill) and skin (T skin ; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results.
Results
Peak T core during competition reached 39.6°C±0.6°C (maximum 41.1°C). T skin decreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (p<0.001). T core was not related to DNF (25% of starters) or medical events (p≥0.150), whereas T skin , T skin rate of decrease and T core -to-T skin gradient were (p≤0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, p<0.001). Athletes (63%) who performed 5–30 days heat acclimation before the competition: ranked better (18±13 vs 28±13, p=0.009), displayed a lower peak T core (39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in T skin (−1.4°C±1.0°C vs −0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179).
Conclusion
T skin , T skin rate of decrease and T core -to-T skin gradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events.
Introduction: This study evaluated how single or combinations of weather parameters (temperature, humidity, wind speed, solar load) affect peak performance during endurance running events and identify which events are most vulnerable to varying weather conditions.
Methods: Results for the marathon, 50km race-walk, 20km race-walk, 10,000m, 5,000m and 3,000m-steeplechase were obtained from the official websites of large competitions. We identified meteorological data from nearby (8.9±9.3 km) weather stations for 1258 races held
between 1936 and 2019 across 42 countries, enabling analysis of 7867 athletes. Results: The Wet-Bulb Globe Temperature (WBGT) across races ranged from -7 to 33°C, with 27% of races taking place in cold/cool, 47% in neutral, 18% in moderate heat, 7% in high heat, and 1% in extreme heat conditions, according to the World Athletics classification. Machine learning decision trees (R2 values: 0.21-0.58) showed that air temperature (importance score: 40%) was the most important weather parameter. But, when used alone, air temperature had lower predictive power (R 2 values: 0.04-0.34) than WBGT (R
2 values: 0.11-0.47). Conditions of 7.5-15°C WBGT (or 10-17.5°C air temperature) increase the likelihood for peak performance. For every degree WBGT outside these optimum conditions, performance declined by 0.3-0.4%. Conclusion: More than one-quarter of endurance running events were held in moderate, high, or extreme heat and this number reaches one-half for events other than the marathon. All four
weather parameters must be evaluated to mitigate the health and performance implications of exercising at maximal intensities in a hot environment with athletes adopting heat mitigation strategies when possible.
Commonly classified as individual, task or environmental, constraints are boundaries which shape the emergence of functional movement solutions. In applied sport, an ongoing challenge is to improve the measurement, analysis and understanding of constraints to key stakeholders. Methodological considerations for furthering these pursuits should be centred around an interdisciplinary approach. This integration of methodology and knowledge from different disciplines also encourages the sharing of encompassing principles, concepts, methods and data to generate new solutions to existing problems. This narrative review discusses how a number of rapidly developing fields are positioned to help guide, support and progress an understanding of sport through constraints. It specifically focuses on examples from the fields of technology, analytics and perceptual science. It discusses how technology is generating large quantities of data which can improve our understanding of how constraints shape the movement solutions of performers in training and competition environments. Analytics can facilitate new insights from numerous and complex data through enhanced non-linear and multivariate analysis techniques. The role of the perceptual sciences is discussed with respect to generating outputs from analytics that are more interpretable for the end-user. Together, these three fields of technology, analytics and perceptual science may enable a more comprehensive understanding of constraints in sports performance.
Historical environmental data from the Boston Marathon affords a pragmatic opportunity to retrospectively quantify how the 2007 earlier start time altered the odds of runner exposures to environmental conditions associated with exertional heat illness.
Purpose:
To compare the wet bulb globe temperature (WBGT) index and other environmental parameters between early and late Boston Marathon race start times from 1995 to 2016.
Methods:
Environmental data from 1995-2016 (excluding 1996) were utilized to compare two identical time frames using the 0900-1300 start versus the 1100-1500 start. This included the WBGT, dry bulb (Tdb), black globe (Tbg), wet bulb (Twb), solar radiation, relative humidity, and air water vapor pressure. To make comparisons between start times, the difference in the area under the curve (AUC) for each environmental variable was compared within each year with a Wilcoxon signed rank test with a Holm-Bonferroni correction.
Results:
AUC exposures for WBGT (p = 0.027), Twb (p = 0.031), Tdb (p = 0.027), Tbg (p = 0.055), and solar radiation (p = 0.004) were reduced with an earlier start. AUC for relative humidity and air water vapor pressure were not. Overall, an earlier race start time by two hours (0900 vs 1100) reduced the odds of experiencing a higher flag category 1.42 times (β = 0.1744, p = 0.032).
Conclusions:
The 2007 decision to make the Boston Marathon start time earlier by 2 hours has reduced by ~1.4 times the odds that runners will be exposed to environmental conditions associated with exertional heat illness.
From the use of polyurethane swimsuits to carbon fibre-plated shoes for road racing, the term ‘techno-doping’ has been commonly used in categorising the use of technology as ‘strategies’ for performance enhancement in sports. There are various types of ‘strategies’ which are regularly (and increasingly) used by athletes to enhance their performance, especially in elite sports, such as the use of actual substances, methods of administering substances, and other modes of ‘strategies’ which have the effect of enhancing the performance of the athletes. However, it is curious that at present, only few ‘Performance-Enhancing Strategies’ (‘PESs’) are regulated, such as the use of Performance-Enhancing Drugs and methods (‘PEDs’) under the World Anti-Doping Agency (‘WADA’) Code. There are other PESs which are wholly unregulated, such as the use of nutrition and haematology, environmental factors, physiology testing opportunities, and sports equipment and technology [hereinafter known as Non-Doping Performance-Enhancing Strategies (‘NDPESs’)]. This paper discusses the unequal treatment between the regulation of PEDs and NDPESs in elite sports, and will conclude that steps ought to be taken in order to harmonise the treatment and regulation of all PESs in elite sports.
Objectives
The ACSM recommends drinking to avoid loss of body mass >2% during exercise to avert compromised performance. Our study aimed to assess the level of dehydration in elite runners following a city marathon in a tropical environment.
Design
Prospective cohort design.
Methods
Twelve elite runners (6 males, 6 females; age 24–41 y) had body mass measured to the nearest 0.01 kg in their race attire immediately before and after the 2017 Standard Chartered Singapore Marathon 2017. Body mass change was corrected for respiratory water loss, gas exchange, and sweat retained in clothing, and expressed as % of pre-race mass (i.e. % dehydration).
Results
Data are expressed as means ± SD (range). Dry bulb temperature and humidity were 27.9 ± 0.1 °C (27.4–28.3 °C) and 79 ± 2% (73–82%). Finish time was 155 ± 10 min (143−172 min). Male runners finishing positions ranged from 2–12 out of 7627 finishers, whilst female runners placed 1–8 out of 1754 finishers. Body mass change (loss) and % dehydration for all runners were 2.5 ± 0.5 kg (1.8–3.5 kg) and 4.6 ± 0.9% (3.6–6.8%). Male runners experienced body mass loss of 2.8 ± 0.5 kg and 4.9 ± 1.2% while females experienced body mass loss of 2.1 ± 0.2 kg and 4.3 ± 0.6%.
Conclusions
Despite experiencing dehydration (4.6% body mass loss) two-fold higher than current fluid replacement guidelines recommend (≤2%), elite male and female runners performed successfully and without medical complication in a hot weather marathon.
Competitive runners seek to control as many performance variables as possible when preparing for peak competition. However, race day weather is out of an athlete's control and can have a profound impact on performance. This review defines hot weather in terms of running performance, details the physiology underlying heat-related performance decrements, and discusses strategies that may mitigate the negative impact of heat on cardiovascular strain and attenuate reductions in heat-related running performance.
Exercise-heat exposure results in significant sweat losses due to large biophysical requirements for evaporative heat loss. Progressive body water losses will increase plasma tonicity and decrease blood volume (hypertonic–hypovolemia). The result is reduced dry and evaporative heat exchange through alterations in the core temperature threshold for initiation of skin blood flow and sweating as well as changes in the sensitivity of these thermo-effectors. Regulation of reduced sweating conserves body water, which reduces heat loss and increases exercise hyperthermia, but the magnitude of this effect is modified by environmental heat transfer capabilities. The focus of this paper is to (1) examine the major mechanisms by which hypohydration alters thermoregulatory responses in the heat, and (2) illustrate how important differences in environmental airflow characteristics between laboratory and field settings may modify these effects.
The largest mass participation fun run in the world took place in
Auckland, New Zealand where an estimated 80000 participants ran 10.4 km
`Round the Bays' in the early fall of 1982. Even in the relatively mild
climate of Auckland, heat stroke and other types of heat illness occur
during this annual event. Techniques for thermal assessment of human
bioclimate have not been applied to an exercising crowd although it is
widely accepted that crowding will reduce the heat loss of individuals.
To quantify the possible heat load brought about by running in a large
crowd, those components of the microenvironment that affect radiant,
evaporative and convective heat exchange were measured, both within the
mass of runners and separately from it. These data were used as input
for two detailed body-environment heat exchange models which show the
effect of the runners themselves on the thermal environment. Since it is
assumed that changes longwave radiation exchange and convective losses
from the body are likely to be the major causes of differences between
solo and group running, these avenues of heat exchange are carefully
assessed . The results show that longwave radiative losses can be
reduced substantially by running in a lame group compared to solo
running, but the absolute size of the increase in net heat load on the
individual is small. However, heat loss by convection for group runners
is less than half that for sole runners. This may be the result of
entertainment of air within an atmospheric envelope below head level in
which wind speed and direction are the same as the runner's and
direction. For the weather conditions prevailing at the time of the
experiment, jogging in the main bunch of runners is estimated to cause,
on occasions, more than three times the heat stress on the body compared
to that experienced when running solo along the same route at the same
time of day during identical weather conditions.
The sections in this article are:
Ingestion of approximately 30-60 g of carbohydrate during each hour of exercise will generally be sufficient to maintain blood glucose oxidation late in exercise and delay fatigue. Since the average rates of gastric emptying and intestinal absorption exceed 1,250 ml.h-1 for water and solutions containing up to 8% carbohydrate, exercising people can be supplemented with both carbohydrate and fluids at relatively high rates. When cyclists exercise at competitive intensities for 2 h in the heat with a sweat rate of 1,400 ml.h-1, it is clear that the closer that fluid consumption matches sweating rate (at least up to 80% of sweating rate), the better. Increasing dehydration, due to inadequate fluid consumption, directly impairs stroke volume, cardiac output, and skin blood flow, which results in larger increases in body core temperature, heart rate, and ratings of the difficulty of exercise. This same phenomenon probably also applies to running, which argues against the notion that a certain amount of dehydration (i.e., up to 3%) is permissible and without major cardiovascular consequences. However, runners generally drink only 500 ml.h-1 of fluid and thus allow themselves to dehydrate at rates of 500-1,000 ml.h-1. The performance question boils down to "Will the time lost as a result of drinking larger volumes be compensated by the physiological benefits drinking produces and the faster running pace that might be achieved during the last half of the race?" However, if the goal is safety, which means minimizing hyperthermia, there is no question that the closer that the rate of drinking can match the rate of dehydration, the better.
This study determined whether 1) exhaustion from heat strain occurs at the same body temperatures during exercise in the heat when subjects are euhydrated as when they are hypohydrated, 2) aerobic fitness influences the body temperature at which exhaustion from heat strain occurs, and 3) curves could be developed to estimate exhaustion rates at a given level of physiological strain. Seventeen heat-acclimated men [maximal oxygen uptake (VO2max) from 45 to 65 ml.kg-1.min-1] attempted two heat stress tests (HSTs): one when euhydrated and one when hypohydrated by 8% of total body water. The HSTs consisted of 180 min of rest and treadmill walking (45% VO2max) in a hot-dry (ambient temperature 49 degrees C, relative humidity 20%) environment. The required evaporative cooling (Ereq) exceeded the maximal evaporative cooling capacity of the environment (Emax); thus thermal equilibrium could not be achieved and 27 of 34 HSTs ended by exhaustion from heat strain. Our findings concerning exhaustion from heat strain are 1) hypohydration reduced the core temperature that could be tolerated; 2) aerobic fitness, per se, did not influence the magnitude of heat strain that could be tolerated; 3) curves can be developed to estimate exhaustion rates for a given level of physiological strain; and 4) exhaustion was rarely associated with a core temperature up to 38 degrees C, and it always occurred before a temperature of 40 degrees C was achieved. These findings are applicable to heat-acclimated individuals performing moderate-intensity exercise under conditions where Ereq approximates or exceeds Emax and who have high skin temperatures.
This investigation represents a descriptive summary of a limited number of marathon runners. As preliminary work it warrants the following observations and conclusions: Elite class male and female distance runners have been described as slight in build, with little body fat and large lung volumes. The marathon runners of this study, although not elite performers, did not differ from those previously described. The 'above average' female and 'average' male marathoners studied here were able to work at a high fraction of their aerobic power for a prolonged period. The fractional utilization of aerobic capacity was similar to that reported for elite male performers. The women studied performed the marathon at least as well and perhaps better than men with similar maximal aerobic capacities relative to body weight. It is estimated that male and female subjects expended 2903 and 2191 kcal respectively, to complete the 42.2 km distance.
Marathon races are performed over a broad range of environmental conditions. Hyperthermia is a primary challenge for runners in temperate and warm weather, but hypothermia can be a concern during cool-wet or cold conditions. Body temperature during the marathon is a balance between metabolic heat production and exchange with the environment described by the heat balance equation. During exercise, core temperature is proportional to the metabolic rate and largely independent of a wide range of environmental conditions. In temperate or cool conditions, a large skin-to-ambient temperature gradient facilitates radiant and convective heat loss, and reduces skin blood flow requirements, which may explain the tolerance for high core temperature observed during marathons in cool conditions. However, in warmer environments, skin temperatures and sweating rates increase. In addition, greater skin blood flow is required for heat loss, magnifying thermoregulatory and circulatory strain. The combined challenge of exercise and environment associated with marathon running can substantially challenge the human thermoregulatory system.
Purpose:
The purpose of this study was to assess research aimed at measuring performance enhancements that affect success of individual elite athletes in competitive events.
Analysis:
Simulations show that the smallest worthwhile enhancement of performance for an athlete in an international event is 0.7-0.4 of the typical within-athlete random variation in performance between events. Using change in performance in events as the outcome measure in a crossover study, researchers could delimit such enhancements with a sample of 16-65 athletes, or with 65-260 in a fully controlled study. Sample size for a study using a valid laboratory or field test is proportional to the square of the within-athlete variation in performance in the test relative to the event; estimates of these variations are therefore crucial and should be determined by repeated-measures analysis of data from reliability studies for the test and event. Enhancements in test and event may differ when factors that affect performance differ between test and event; overall effects of these factors can be determined with a validity study that combines reliability data for test and event. A test should be used only if it is valid, more reliable than the event, allows estimation of performance enhancement in the event, and if the subjects replicate their usual training and dietary practices for the study; otherwise the event itself provides the only dependable estimate of performance enhancement. Publication of enhancement as a percent change with confidence limits along with an analysis for individual differences will make the study more applicable to athletes. Outcomes can be generalized only to athletes with abilities and practices represented in the study.
Conclusion:
estimates of enhancement of performance in laboratory or field tests in most previous studies may not apply to elite athletes in competitive events.
Four environmental conditions contribute to climatic heat stress: ambient temperature, air humidity, air movement, and radiant heat from the sun and nearby warm surfaces. If sufficiently great, this climatic heat stress can adversely affect the performance of work or exercise. Particularly for endurance sport activities, such as marathon running, racewalking, and other sustained distance events, the ability to quantify the magnitude of heat stress is of value in helping both coach and athlete plan the safest competitive strategy. Quantification of climatic heat stress is possible through the use of three thermometers, which measure shade temperature (dry bulb temperature [DBT]), the effect of wind and humidity (wet bulb temperature [WBT]), and radiant energy (black globe temperature [BGT]). The three values are incorporated into a heat stress index (HSI), a temperature value comprised of 10% of DBT, 20% of BGT, and 70% of WBT. Extensive HSI monitoring was performed at the 1992 Barcelona Olympic Games, on‐site during all of the endurance competitions (10, 20, 50 km racewalks, marathons, and modem pentathlon cross country). These data provided the first in‐depth assessment of the extent to which the athlete is able to compete successfully under conditions ranging from high risk to extreme risk heat stress with minimal actual heat injury. This success is due in part to the adaptation in tolerating heat stress that occurs with training, as well as the instinctive reduction in pace adopted by the athlete to permit the optimum balance of skin and muscle blood flow that keeps core temperature from rising too high.
Climatic heat stress measurements were made during 1992, 1993, 1994, and 1995 at the Atlanta Centennial Olympic Stadium construction site, using three commercially available heat stress monitoring devices. This venue will be the site of opening and closing ceremonies, as well as all of the athletics competition. The measurement periods were during late July and early August, the period corresponding to the planned 1996 Games competition days. Whereas the 1992 data were of a more general nature, and thus preliminary, in 1993, 1994, and 1995 detailed measurements were made at 5‐minute intervals during selected 4‐hour periods. The potentially high temperature, humidity, and radiant heating in Atlanta during the Games period to which athletes, spectators, officials, and media could be exposed warranted such detailed studies. Measurements included dry bulb temperature, wet bulb temperature, and black globe temperature. From these values, the heat stress index temperature was calculated. The time periods were in the morning (7:00 through 11:00 AM), in the afternoon (12:30 through 4:30 PM), and in the evening (6:00 through 10:00 PM). Also, in 1994 data were obtained during the 50 km Pan American Race Walk Cup held in September as the first official pre‐Olympic athletic test event. Considerable variability in weather occurred during the 4 identical calendar year periods of July and August, which is described. From these data, it is also possible to estimate and compare the average heat stress encountered during specific time periods. In turn, this permits consideration of whether the heat stress during one period might be preferable to another (for example, early morning versus early evening) regarding the staging of an outdoor endurance event that requires a few hours to complete, such as a marathon or walk.
This paper briefly reviews certain aspects of man's response on exposure to a hot climate. The value of applying the concepts of thermal exchange analysis to evaluate the severity of a particular heat stress situation is emphasised. The possible effects of the Rome climate on a marathon runner competing in the 1900 Olympic Games is used as an illustration. It is concluded that with more knowledge of the physiology of athletes the accuracy of such predictions could be much increased, and might then be helpful to the athlete in planning the strategy of his race.
Sex differences in competitiveness are well established, but it is unknown if they originate from sociocultural conditions or evolved predispositions. Testing these hypotheses requires a quantifiable sex difference in competitiveness and the application of a powerful sociocultural manipulation to eliminate it. Study 1 reviews previous work showing that more male distance runners are motivated by competition and maintain large training volumes, suggesting that more males should run fast relative to sex-specific world-class standards. I then use two independent statistical approaches to demonstrate that, in matched populations of male and female U.S. runners, two to four times as many males as females ran relatively fast in 2003. Study 2 investigates whether the growth in opportunities and incentives for female athletes in the past 30 years is eliminating this sex difference. I first show that there was a marked increase in the number of fast female runners in the 1970s and early 1980s, a period during which female participation increased dramatically. However, I found no indication of an absolute or relative increase in the number of fast female distance runners since the mid-1980s. These findings therefore support the hypothesis that sex differences in competitiveness partly reflect evolved predispositions.
The aerobic performance of thirteen male ultramarathon and nine female marathon runners were studied in the laboratory and their results were related to their times in events ranging in distance from 5 km to 84.64 km.
The mean maximal aerobic power output (VO2 max) of the men was 72.5 ml/kg·min compared with 58.2 ml/kg·min (p<0.001) in the women but the O2 cost (VO2) for a given speed or distance of running was the same in both sexes. The 5 km time of the male athletes was closely related to their VO2 max (r=−0.85) during uphill running but was independent of relative power output (%VO2 max). However, with increasing distance the association of VO2 max with male athletic performance diminished (but nevertheless remained significant even at 84.64 km), and the relationship between VO2 max and time increased. Thus, using multiple regression analysis of the form: $$\begin{gathered} 42.2 km (marathon) time (h) = 7.445 - 0.0338 \dot V{\text{O}}_{{\text{2 max}}} ({\text{ml/kg }} \cdot {\text{ min}}) \hfill \\ - 0.0303\% \dot V{\text{O}}_{{\text{2 max}}} (r = 0.993) \hfill \\ \end{gathered} $$ and $$\begin{gathered} 84.64 {\text{km (London}} - {\text{Brighton) time (h) = 16}}{\text{.998 }} - {\text{ 0}}{\text{.0735 }}\dot V{\text{O}}_{{\text{2 max}}} \hfill \\ ({\text{ml/kg }} \cdot \min ) - 0.0844\% \dot V{\text{O}}_{{\text{2 max}}} (r = 0.996) \hfill \\ \end{gathered} $$ approximately 98% of the total variance of performance times could be accounted for in the marathon and ultramarathon events. This suggests that other factors such as footwear, clothing, and running technique (Costill, 1972) play a relatively minor role in this group of male distance runners. In the female athletes the intermediate times were not available and they did not compete beyond 42.2 km (marathon) distance but for this event a similar association though less in magnitude was found with VO2 max (r=−0.43) and %VO2 max (= −0.49). The male athletes were able to sustain 82% VO2 max (range 80–87%) in 42.2 km and 67% VO2 max (range 53–76%) in 84.64 km event. The comparable figure for the girls in the marathon was 79% VO2 max (ranges 68–86%). Our data suggests that success at the marathon and ultramarathon distances is crucially and (possibly) solely dependent on the development and utilisation of a large VO2 max.
The relationships between the results of Beijing International Marathon Races and the corresponding weather conditions are analysed quantitatively. There are obvious interrelationships between the marathon results and weather factors such as air temperature, wet bulb temperature and human biometeorological indices. For example, the correlation coefficient between the average times of the top ten finishers and temperature is r = 0.8910. The meteorological conditions are classified into three categories, suitable, moderate and unsuitable for running a marathon race, and the optimum meteorological index is given. Also the concept of a meteorological result, i.e. the part of the actual performances fluctuating with the changes in weather conditions, is presented. This plays an important role in some kinds of sports such as marathon racing. Finally, the results of physiological tests are given, which illustrate the physiological reactions of long- and middle-distance runners to the surrounding temperature.
Air temperature and relative humidity have long been suspected of affecting the performance of marathon runners. Though these factors are important in their extremes, we show that other factors are even more indicative of race performances. Performances of the top 3 finishers in the last 30 Boston Marathons were correlated with hourly meteorological data for each race day. These 90 individual performances were classified as: record breaking performances (31), average performances (35), and unusually slow performances (24). The factors that help predict record breaking and unusually slow performances are: (i) wet bulb temperature, (ii) percent sky cover, and (iii) presence or absence of a light precipitation. Record breaking performances are characterized by a wet bulb temperature of less than 7.8 degrees C, and 100% sky cover. A light drizzle is also conducive to better performances. On the other hand, unusually low performances are accompanied by a wet bulb temperature of greater than 7.8 degrees C, and a sky cover of 50% or less. No light precipitation was recorded on any of the unusually slow race days. A graphic analysis clearly shows these relationships to exist. In addition, a multiple regression analysis confirms the importance of these variables. The authors advise that these are reliable predictors; however, when considering marathon races held in various geographical regions and differing climatic regimes, the exact numerical thresholds used here may not apply.
The physiology of marathon running has been extensively studied both in the laboratory and in the field, but these investigations have been confined to elite competitors. In the present study 28 competitors who took part in a marathon race (42.2 km) have been studied; 18 male subjects recorded times from 2 h 19 min 58 s to 4 h 53 min 23 s; 10 female subjects recorded times between 2 h 53 min 4 s and 5 h 16 min 1 s. Subjects visited the laboratory 2-3 weeks after the race and ran on a motor driven treadmill at a series of speeds and inclines; oxygen uptake (VO2) was measured during running at average marathon racing pace. Maximum oxygen uptake (VO2 max) was measured during uphill running. For both males (r = 0.88) and females (r = 0.63), linear relationships were found to exist between marathon performance and aerobic capacity. Similarly, the fraction of VO2 max which was sustained throughout the race was significantly correlated with performance for both male (r = 0.74) and female (r = 0.73) runners. The fastest runners were running at a speed requiring approximately 75% of VO2 max; for the slowest runners, the work load corresponded to approximately 60% of VO2 max. Correction of these estimates for the additional effort involved in overcoming air resistance, and in running on uneven terrain will substantially increase the oxygen requirement for the faster runners, while having a much smaller effect on the work rate of the slowest competitors. Five minutes of treadmill running at average racing pace at zero gradient did not result in marked elevation of the blood lactate concentration in any of the subjects.
Grandma's Marathon has been run each year in June since 1977 in Duluth, MN. It is ranked in the top 20 marathons and in 1993 was ranked the ninth largest and fourth fastest in the United States. As Grandma's Marathon continues to grow each year, so do concerns for the runners' safety. A half marathon was added in 1991 and earlier race times have been implemented to make the race safer for the runners. During the years of 1989-1995, data from the medical tent, weather bureau, and race booklets were analyzed using odds ratios to predict factors associated with a need for medical assistance. The odds of needing assistance were almost two times higher before implementing the half marathon and the odds of needing assistance decreased with earlier start times. Except for 1994 when the race was later, the percent of finishers seeking medical attention has decreased each year, a fact that we feel is a direct result of these race changes. Thus, the addition a half marathon and earlier start times can help decrease the number of people needing medical assistance.
In 1974 two sets of heat stress guidelines, each based on the wet bulb globe temperature (WBGT) index, were designed for men's National Collegiate Athletic Association (NCAA) Championship Division I distance running competitions. One set of guidelines was established to minimize the chance of heat injury during distance running events. A second set was designed to predict heat stress related performance decrements. During the time the heat injury guidelines were used (1974-1993), no heat injuries were reported. The purpose of this study was to assess the accuracy of the performance decrement guidelines and determine whether the WBGT indices were linearly related to men's championship distance running performance. WBGT index data were collected during the 1500-, 3000-steeplechase (SC), 5000-, and 10,000-m events at men's NCAA Division I Track and Field Championships held from 1974 to 1981 (excluding 1975). These data were compared to the average running performance of the top six finishers in each event. Analysis of the accuracy of the NCAA performance decrement guidelines revealed four unexpected performances out of 28 predictions. Pearson product-moment correlation and linear regression analyses between the WBGT indices and performance revealed statistically significant linear relationships for the 3000-SC and 10,000-m events (P < 0.05). A significant linear relationship was also found when the 1500-, 3000-SC, 5000-, and 10,000-m results were pooled (P < 0.05). In conclusion, the NCAA guidelines were effective in preventing heat injury and fairly successful in predicting performance. However, a linear relationship between WBGT indices and distance running performance did not exist in all running events.
Eight healthy males performed four rides to exhaustion at approximately 70% of their VO2max obtained in a neutral environment. Subjects cycled at ambient temperatures (Ta) of 3.6 +/- 0.3 (SD), 10.5 +/- 0.5, 20.6 +/- 0.2, and 30.5 +/- 0.2 degrees C with a relative humidity of 70 +/- 2% and an air velocity of approximately 0.7 m.s-1. Weighted mean skin temperature (Tsk), rectal temperature (Tre), and heart rate (HR) were recorded at rest, during exercise and at exhaustion. Venous samples were drawn before and during exercise and at exhaustion for determination of hemoglobin, hematocrit, blood metabolites, and serum electrolytes and osmolality. Expired air was collected for calculation of VO2 and R which were used to estimate rates of fuel oxidation. Ratings of perceived exertion (RPE) were also obtained. Time to exhaustion was significantly influenced by Ta (P = 0.001): exercise duration was shortest at 30.5 degrees C (51.6 +/- 3.7 min) and longest at 10.5 degrees C (93.5 +/- 6.2 min). Significant effects of Ta were also observed on VE, VO2, R, estimated fuel oxidation, HR, Tre, Tsk, sweat rate, and RPE. This study demonstrates that there is a clear effect of temperature on exercise capacity which appears to follow an inverted U relationship.
Equivalence trials aim to show that two treatments have equivalent therapeutic effects. The approach is to define, in advance, a range of equivalence -d to +d for the treatment difference such that any value in the range is clinically unimportant. If the confidence interval for the difference, calculated after the trial, lies entirely within the interval, then equivalence is claimed. Glaxo Wellcome has carried out a series of trials using this methodology to assess new formulations of inhaled beta-agonists and inhaled steroids in asthma. Eleven of these trials are used to review some practical issues in equivalence trials. For the series of asthma trials, a range for peak expiratory flow rate (PEF) from -15 to +15 l/min was chosen to be the range of equivalence. This fitted well with physicians' opinions and with previously demonstrated differences between active and placebo. The choice of the size of the confidence interval should depend on the medical severity of the clinical endpoints under consideration and the level of risk acceptable in assuming equivalence if a difference of potential importance exists. From this point of view, a recommendation in the CPMP Note for Guidance on Biostatistics that 95 per cent confidence intervals should be used is inappropriate. Intent-to-treat (ITT) and per-protocol (PP) analyses were compared for the eleven asthma trials. Confidence intervals were always wider for the PP analysis and this was entirely due to the smaller number of subjects included in the PP analysis. There was no evidence that the ITT analyses were more conservative in their estimates of treatment difference. The need to demonstrate equivalence in both an ITT and a PP analysis in a regulatory trial increases the regulatory burden on drug developers. The relative importance of the two analyses will depend on the definitions used in particular therapeutic areas. Demonstrating equivalence in one population with strong support from the other would be preferred from the Industry viewpoint. In trials with regulatory importance, prior agreement with regulators on the role of ITT and PP populations should be sought. Trial designs will need to take account of the estimated size of the PP population if adequate power is needed for both analyses. Careful design in the series of asthma trials, particularly identifying a population of patients with potential to improve, resulted in notable increases in lung function during the course of the trials for both treatments. This provided reassurance that equivalence was not due to a lack of efficacy for both treatments. In one trial equivalence was demonstrated overall but a treatment by country interaction was noted. However, this interaction could not be attributed to differences in patient characteristics or baseline data between the countries. Study conduct was also similar in the different countries. The conclusion was that the interaction was spurious and that the trial provided good evidence of equivalence.
The purpose of this study was to assess research aimed at measuring performance enhancements that affect success of individual elite athletes in competitive events.
Simulations show that the smallest worthwhile enhancement of performance for an athlete in an international event is 0.7-0.4 of the typical within-athlete random variation in performance between events. Using change in performance in events as the outcome measure in a crossover study, researchers could delimit such enhancements with a sample of 16-65 athletes, or with 65-260 in a fully controlled study. Sample size for a study using a valid laboratory or field test is proportional to the square of the within-athlete variation in performance in the test relative to the event; estimates of these variations are therefore crucial and should be determined by repeated-measures analysis of data from reliability studies for the test and event. Enhancements in test and event may differ when factors that affect performance differ between test and event; overall effects of these factors can be determined with a validity study that combines reliability data for test and event. A test should be used only if it is valid, more reliable than the event, allows estimation of performance enhancement in the event, and if the subjects replicate their usual training and dietary practices for the study; otherwise the event itself provides the only dependable estimate of performance enhancement. Publication of enhancement as a percent change with confidence limits along with an analysis for individual differences will make the study more applicable to athletes. Outcomes can be generalized only to athletes with abilities and practices represented in the study.
estimates of enhancement of performance in laboratory or field tests in most previous studies may not apply to elite athletes in competitive events.
The typical variation in an athlete's performance from race to race sets a benchmark for assessing the utility of performance tests and the magnitude of factors affecting medal prospects. We report here the typical variation in competitive performance of endurance runners.
Repeated-measures analysis of log-transformed official race times provided the typical within-athlete variation in performance as coefficients of variation (CV). The types of race were cross-country runs (4 races over 9 wk), summer road runs (5 races over 4 wk), winter road runs (4 races over 9 wk), half marathons (3 races over 13 wk and 2 races over 22 wk), and marathons (2 races over 22 wk).
Typical variation of times for the fastest quartile of male runners was 1.2-1.9% in the cross-country and road runs, 2.7% and 4.2% in half marathons, and 2.6% in marathons. Times for the slower half of runners in most events were more variable than those of the faster half (ratio of slower/faster CV, 1.0-2.3). Times of younger adult runners were more variable than times of older runners (ratio of younger/older CV, 1.1-1.8). Times of male runners were generally more variable than those of female runners (ratio of male/female CV, 0.9-1.7).
Tests of endurance power suitable for assessing the smallest worthwhile changes in running performance for top runners need CV < or = 2.5% and < or = 1.5% for tests simulating half or full marathons and shorter running races, respectively. Most of the differences in variability of race times between types of race, ability groups, age groups, and sexes probably arise from differences in competitive experience and attitude toward competing.
Null hypothesis statistical testing (NHST) has been debated extensively but always successfully defended. The technical merits of NHST are not disputed in this article. The widespread misuse of NHST has created a human factors problem that this article intends to ameliorate. This article describes an integrated, alternative inferential confidence interval approach to testing for statistical difference, equivalence, and indeterminacy that is algebraically equivalent to standard NHST procedures and therefore exacts the same evidential standard. The combined numeric and graphic tests of statistical difference, equivalence, and indeterminacy are designed to avoid common interpretive problems associated with NHST procedures. Multiple comparisons, power, sample size, test reliability, effect size, and cause-effect ratio are discussed. A section on the proper interpretation of confidence intervals is followed by a decision rule summary and caveats.
Three subjects walked continuously on a treadmill for periods of 1 hr or more at 180, 300, or 420 kcal/hr in a range of cool and hot climates from corrected effective temperature (CET) 10–32 C. At each rate of work rectal thermal equilibrium was practically independent of the influence of environment over a wide range of climates (“prescriptive” zone); the upper limit of the prescriptive zone appeared to be associated with the minimal bodily thermal gradient compatible with the transfer of adequate amounts of heat from the core to the periphery without placing the thermoregulatory system under disproportionately increased strain, in terms of circulatory response and elevated body core temperature; as such, this seems to be one possible criterion by which thermal environmental limits for everyday work may be assessed. The upper limits of prescriptive zones for work at an energy expenditure of 300 kcal/hr is CET 27.4 C and those for the lower and higher rates of work, respectively, were CET 30.2 C and 26.9 C.
Submitted on June 15, 1962
The stressful microclimate created by massed funrunners
- N J Dawson
- C R De Freitas
- W J Mackey
- A A Young
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crease the incidence of hyponatremia and heat 8. Roberts WO. A twelve year profile of medical injury and illness for the Twin Cities Marathon
crease the incidence of hyponatremia and heat
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tion coefficients are most closely linked with the 10 Exertional heat illness during training and competition
- Le Armstrong
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for road racing with a WBGT up to 28ºC (82ºF) may 4. ((Note: add page numbers when finalised.))Kenefick RW, Cheuvront SN, Sawka MN. Thermoregulatory function during be too liberal for acceptable community emergency the marathon
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4. ((Note: add page numbers when finalised.))Kenefick RW,
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Wet-cold exposure and hyincreases both the finish-line medical encounter rate pothermia: thermal and metabolic responses to prolonged exand the on course drop-out rate, and seems to inercise in rain
- Rl Thompson
- Js Hayward
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Hot conditions in particular stress the community medical resources Correspondence: Dr William O. Roberts, Phalen Village and the effects of heat on combined drop-out and Clinic, 1414 Maryland Avenue E
- Start Tcm
- At Boston Marathon
TCM and start at Boston Marathon). Hot conditions
in particular stress the community medical resources Correspondence: Dr William O. Roberts, Phalen Village
and the effects of heat on combined drop-out and Clinic, 1414 Maryland Avenue E, St Paul, MN 55106, USA.
medical encounter incidence suggests that the pa-E-mail: rober037@umn.edu
It is not clear 1 American College of Sports Medicine Position statement on from the data at what temperature an acceptable heat and cold illnesses during distance running): i-vii casualty rate changes to unacceptable and when a 2
decreased for the regular population. It is not clear
1. American College of Sports Medicine. Position statement on
from the data at what temperature an acceptable
heat and cold illnesses during distance running. Med Sci
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