ArticlePDF AvailableLiterature Review


The goal of training is to prepare the distance athlete to perform at his or her best during major competitions. Whatever the event, nutrition plays a major role in the achievement of various factors that will see a runner or walker take the starting line in the best possible form. Everyday eating patterns must supply fuel and nutrients needed to optimize their performance during training sessions and to recover quickly afterwards. Carbohydrate and fluid intake before, during, and after a workout may help to reduce fatigue and enhance performance. Recovery eating should also consider issues for adaptation and the immune system that may involve intakes of protein and some micronutrients. Race preparation strategies should include preparation of adequate fuel stores, including carbohydrate loading for prolonged events such as the marathon or 50-km walk. Fluid and carbohydrate intake during races lasting an hour or more should also be considered. Sports foods and supplements of value to distance athletes include sports drinks and liquid meal supplements to allow nutrition goals to be achieved when normal foods are not practical. While caffeine is an ergogenic aid of possible value to distance athletes, most other supplements are of minimal benefit.
Nutrition for distance events
Louise M Burke1, Gregoire Millet2, Mark A Tarnopolsky3
1Department of Sports Nutrition, Australian Institute of Sport, Belconnen, Australia 2616
2 Department of performance enhancement, Aspire, PO Box 22287, Doha, Qatar
3 Departments of Pediatrics and Medicine, McMaster University, Hamilton, Canada.
Corresponding author:
Louise M Burke,
Department of Sports Nutrition,
Australian Institute of Sport,
Australia 2616
Ph 61 2 6214 1351
Fax 61 2 6214 1603
Running title: Nutrition for distance events
The goal of training is to prepare the distance athlete to perform at his or her
best during major competitions. Whatever the event, nutrition plays a
substantial role in the achievement of various factors that will see a runner or
walker take the starting line in the best possible form. Everyday eating
patterns must supply fuel and nutrients needed to optimise their performance
during training sessions and to recover quickly afterward. Carbohydrate and
fluid intake before, during, and after a workout may help to reduce fatigue
and enhance performance. Recovery eating should also consider issues for
adaptation and the immune system which may involve intakes of protein and
some micronutrients. Race preparation strategies should include preparation
of adequate fuel stores, including carbohydrate loading for prolonged events
such as the marathon or 50 km walk. Fluid and carbohydrate intake during
races lasting an hour or longer should also be considered. Sports foods and
supplements of value to distance athletes include sports drinks and liquid
meal supplements to allow nutrition goals to be achieved when normal foods
are not practical. While caffeine is an ergogenic aid of possible value to
distance athletes, most other supplements are of minimal benefit.
There are a large number of events which involve prolonged effort within the
IAAF umbrella of track and field, road running, cross country, and race-
walking. Events commonly undertaken by elite competitors include the 5,000
and 10,000 m track events, the half-marathon and marathon, the 20 and 50
km walks and cross-country runs (8 km for females and 12 km for males). In
addition, there is a vast array of “fun runs” and community events around the
world which can attract large fields ranging from the elite to the weekend
warrior. Nutrition plays a key role in assisting distance athletes of all levels to
achieve their training and competition goals.
Training for distance runners and walkers
Distance runners follow a periodised training program (see Stellingwerff et
al., 2007), split into base training (8 to 16 weeks), a precompetitive period (8-
6 weeks) and a competitive period (if track events) or a tapering phase (up to
3 weeks) prior to a marathon followed by a short transition/recovery phase.
Heat acclimatisation before competition in a hot environment and altitude
training are other specialised training techniques often undertaken by
distance runners and walkers. Altitude training remains a controversial area,
with coaches and scientists still arguing over the benefits of periods in a
hypoxic (lower oxygen) environment on performance at sea level. Distance
athletes who usually reside at low altitudes have a variety of options for
undertaking altitude training (see Hawley et al., 2007).
Since the athletes of East Africa origins (Kenya, Ethiopia and more recently,
Eritrea and Uganda) dominate distance running, the reasons for their
superiority have been extensively studied (Billat et al., 2003; Lucia et al.,
2007; Saltin et al. 1995). Among the key physiological factors of distance
running performance (i.e. VO2max, the maximal fraction of VO2max sustained
during the event, the velocity at lactate threshold and the running energy
cost), it appears that they have mainly a greater running economy (Lucia et
al., 2006) and a higher fractional utilisation of VO2max than Caucasian runners
(Saltin et al., 1995; Lucia et al., 2006). The underlying mechanisms of these
differences are still contradictory but are a combination of social, genetic and
anthropometric/biomechanical factors. The effects of the altitude
residence/training per se or of nutritional differences have not been identified.
Although a high running distance in training (80-150 km.wk-1 in 3,000–5,000
m runners; 150-220 km.wk-1 in marathon runners during base training) is
commonly observed in all distance runners, several studies have reported
that most African runners spend a larger part of their weekly training at high
relative intensity. The current trend in distance running is to a ‘polarised
training’ model; i.e. a large percentage (70-75%) at strictly aerobic intensity,
a small percentage (<10%) of ‘Tempo’ training at around or above lactate
threshold and 15-20% at high intensity.
Competition in distance events
Although most distance events involve a single race, there are some events
which require heats and finals (e.g. 5,000 and 10,000 m on the Olympic
Games and World Championship programs). Most distance runners and
walkers peak for several important events in a year (e.g. a Big City Marathon
or the World Championships). However, there may be other situations in
which they compete in a series of races including the lucrative professional
circuit in Europe, meets within a university circuit such as the NCAA season,
or in the cross-country schedule for club athletes. In general, the main
competition for track and field occurs in summer, whereas cross-country has
an autumn and/or winter season. Most road races attracting large fields of
both elite and community-based participants are scheduled over the warmer
months from spring to late autumn where heat and hydration become more
of an issue. The schedule of Big City Marathons, which includes races in
Boston, Chicago, New York, London, and Paris, extends from April to
Aerobic metabolism typically accounts for more than 95% of the energy cost
of long-distance events, especially half-marathon and marathon races and
the longer walking events. However, there are critical times in all distance
races requiring anaerobic effort—for example, a surge, a hill, or a sprint
finish—that may be the ultimate factor in determining the order of race
finishers. The factors that limit the performance of distance runners and
walkers vary according to the duration and environment of the race and
nutrition is an important factor in success over the duration of the event.
Because many of these factors—such as fluid balance, the availability of
carbohydrate fuel, and even the disturbance to acid-base status arising from
anaerobic glycolysis—can be manipulated by dietary strategies, nutrition is
an important component of the athlete’s preparation for competition.
Nutritional Issues and Challenges
There is a range of common nutritional issues that arise in long-distance
running and walking as a result of issues related to optimal physique,
training, and race day performance. This review will provide an overview of
the major issues.
Very low levels of body fat are a striking feature of successful distance
athletes. However, it is hard to distinguish whether this is a critical factor in
determining successful performance or the outcome of the high training
volumes needed for successful performance. Low levels of both total mass
(which determines the total energy cost of running) and fat mass (dead
weight that must be transported) assist fast and economical movement.
These traits become even more important when the event involves long
distances or moving against gravity (e.g., running up hills in a road or cross
country race). Because upper-body musculature is unimportant for running
performance, elite runners and walkers typically exhibit minimal evidence of
muscle development in their arms and upper torso. Although there is
variability in the size of long-distance runners and walkers, the winners of
“hot weather” races tend to be small and light. A small and compact
physique offers thermoregulatory advantages, both by reducing the absolute
amount of heat that is produced (smaller muscle mass) and by achieving a
more efficient dissipation of heat generated by the body (enhanced ratio of
surface area to volume). There are data from both modelling (Dennis and
Noakes, 1999) and laboratory (Marino et al., 2000) sources to show that
lighter runners store less heat at the same running speed and enjoy an
advantage in conditions where heat dissipation mechanisms are at their limit.
Some runners and walkers achieve a small and very lean frame as a result of
their genetic background and training program. However, other runners with
naturally larger frames or higher levels of adiposity feel that they must whittle
themselves down to an “unnatural” size and body fat level to be competitive.
Although many male runners eat and train specifically to reduce their body
fat and racing weight, the battle for a low percentage of body fat and weight
control is most often identified as a female problem. This may be because
females generally need to push their body characteristics further from their
natural shape than male runners to achieve the leanness that is considered
ideal. Attempts to deviate body fat further from the apparent biological
“default” can have negative effects, including “penalties” resulting from the
low body fat levels per se such as a lack of insulation against cold. Other
penalties arise from the nutrition and training methods used to manipulate
weight and body fat including restricted intakes of energy, protein,
carbohydrate and micronutrients (Burke, 2007). Some athletes develop frank
medical or psychiatric problems such as eating disorders, osteopaenia and
chronic menstrual dysfunction. More develop sub-clinical versions of these
problems; the spectrum of restrained eating, menstrual dysfunction and poor
bone health within the “female athlete triad” is covered in greater detail by
Manore et al. (2007) and similar issues should also be considered in the
evaluation of some male athletes.
The problems associated with poor bone health lie not only with the risk of a
premature onset of osteoporosis but also with the immediate problem of
stress fractures. Recurrent or chronic stress fractures can prevent the
athlete from competing at important times and interfere with his or her ability
to undertake the training volume necessary for high level performance. Many
athletes have had promising careers ended by this injury pattern. Distance
runners and walkers should be encouraged to set realistic weight and body
fat goals; these are specific to each athlete and must be judged by trial and
error over a period of time. Further discussion on dietary strategies to assist
with loss of weight and body fat is found in the review by O’Connor et al.
Poor iron status
There is a common belief that endurance athletes, particularly distance
runners, are at high risk of iron deficiency; this has been given apparent
credibility because the target levels for iron status measures such as serum
ferritin are often set well above those of normal population standards to
provide a “safety margin” for athletes whose performance are underpinned
by the roles of iron in oxygen transport (haemoglobin and myoglobin) and
enzyme function (for review, see Deakin 2006).
The depletion of the body’s iron stores progresses through a number of
stages with different functional and diagnostic criteria (see Deakin 2006). The
literature is unclear, in part because of methodological concerns, whether
iron depletion, in the absence of anaemia impairs exercise performance
(Fogelholm 1995). Some studies of iron supplementation in iron-depleted but
non-anaemic female runners (Klingshirn et al. 1992; Newhouse et al. 1989;
Powell and Tucker 1991) failed to find differences in performance changes
between supplementation and placebo treatment groups, even when serum
ferritin increased with iron therapy (Klingshirn et al. 1992; Newhouse et al.
1989). However, in other studies, female runners with low ferritin levels
experienced a performance improvement, albeit in conjunction with an
increase in haemoglobin levels, after iron supplementation (Lamanca and
Haymes 1993; Schoene et al. 1983). Of course, athletes are also concerned
whether iron depletion affects their ability to recover between workouts or
races. Brownlie et al. (2004) exposed previously untrained participants with
non-anaemic iron depletion to a 4-week training program and found that
those with a tissue iron deficiency (based on abnormal serum transferrin
receptor concentrations) had an impaired adaptation to this training
compared with a similar group who received iron supplements. In contrast,
iron supplementation did not affect endurance cycling performance at the
end of the training program in the iron-depleted group who were not tissue
In summary, the true prevalence of iron-deficiency anaemia in distance
runners and walker is probably not greater than in the general population
(Fogelholm, 1995). However, reduced iron status does occur and may be
problematic for performance or adaptation to training, particularly altitude
training (see Hawley et al., 2007). The cause is essentially the same reason
that it occurs in the general population: a lower than desirable intake of high
bioavailability iron. Iron requirements may be increased in distance athletes
because of increased gastrointestinal or haemolytic iron losses (for review
see Deakin, 2006). However, the most important risk factor is still the low-
energy or low-iron diet. Females, vegetarian eaters, and those following diets
with restricted quantity and variety are at highest risk. Dietary interventions to
reverse or prevent a decline in iron status involve strategies to increase total
iron intake as well as to increase the bioavailability of this iron.
The management and prevention of iron deficiency requires careful diagnosis
using a variety of clinical, haematological, dietary, and medical data.
Haematological and biochemical tests that are routinely measured to indicate
iron status should be undertaken in a way that minimises or standardises the
effect of exercise on the results. In athletic populations, ferritin levels lower
than 30-35 ng/ml (Nielsen and Nachtigall 1998) are generally marked for
further consideration or review, especially where it makes a change in the
established iron status history of the individual. New tests including the
measurement of serum transferrin receptors and the characteristics of
reticulocytes may offer new opportunities. However, these tests are not
routinely available in all laboratories and need to be studied carefully in
relation to iron status in athletes.
Many distance athletes are tempted to self-medicate with iron supplements
that can be purchased over the counter. However, there are several risks
involved with the consumption of iron supplements in the absence of a
confirmed iron status problem, including haemosiderosis or iron overload.
Typically, a 3-month period of supplementation, in the form of a daily dose of
100 mg of elemental iron, is needed to restore depleted iron stores (Nielsen
and Nachtigall 1998). In some cases, when it is not possible to enhance
dietary iron intake sufficiently, iron supplementation is continued at a lower
dose to prevent ongoing iron drain. In cases of extreme iron depletion or
where oral iron intake is not tolerated, intramuscular injections of iron can
achieve a rapid increase in iron stores. However, there is no evidence of
additional performance benefits over oral supplementation, and there are
higher risks of side effects. Iron injections will not increase haemoglobin
levels or other iron parameters in people who are not otherwise suboptimal in
iron status (Ashenden et al. 1998).
Carbohydrate needs for optimal training and recovery
Distance runners and walkers must be able to rapidly recover their muscle
fuel stores between daily or twice-daily sessions, and between races on the
competition circuit. A high-carbohydrate intake enhances the performance of
a single bout of prolonged running as well as the recovery and performance
of a subsequent running bout (Fallowfield and Williams, 1993). However,
muscle glycogen concentrations may not completely recover over 24 to 48 h
following a very strenuous running session (e.g., marathon) or unaccustomed
eccentric loading, despite a plentiful carbohydrate supply (Asp et al. 1997;
Sherman et al. 1983). Unaccustomed muscle damage may cause a
disruption to muscle cell function and may require an increase in total
carbohydrate intake in the first 24 h of recovery (Doyle et al. 1993) or a
greater recovery time (up to 7 days) for full replacement of muscle glycogen.
Logically, benefits from enhancing acute recovery between sessions should
translate over time into better training adaptations and long-term
performance gains. However, the literature, which includes three studies
involving runners, is curiously unclear in showing that high carbohydrate
diets provide superior training outcomes to moderate carbohydrate intakes
(Burke, 2007). Kirwan and colleagues (1988) studied well-trained runners
who increased their training by 150% for 5 days while consuming either high
(8 g/kg/d) or moderate (4 g/kg/d) intakes of carbohydrate. Muscle glycogen
concentration gradually declined in both treatments but was better preserved
with the higher carbohydrate diet; additionally, running economy at two
different running speeds was better. By contrast Sherman and colleagues
(1993) followed 7 days of training in two groups of runners who consumed
daily carbohydrate intakes of either 5 g/kg (gradually reduced muscle
glycogen levels) or 10 g/kg (maintained muscle glycogen concentrations). At
the end of this period, the groups did not differ in their capacity to undertake
two treadmill runs to exhaustion at 80% VO2max with a short recovery
interval at the end of a training session.
Finally, well-trained runners undertook 7 days of intensified training
supported by both moderate- (5.4 g/kg/d) and high- (8.5 g/kg/d) carbohydrate
diets (Achten et al. 2004). Muscle glycogen utilisation decreased during
submaximal running on the moderate-carbohydrate diet and there was a
decline in speed over 8 km (treadmill) and 16 km (outdoor) time-trials.
However, the high-carbohydrate treatment was associated with a smaller
decrease in 8 km speed and maintenance of 16 km performances. The
authors concluded that a high-carbohydrate diet reduced symptoms of
overreaching in runners during intensified training compared with a
moderate-carbohydrate diet but could not prevent it entirely.
An emerging interest is that of dietary periodisation – the so-called “train low,
compete high” approach - in which distance athletes deliberately train with
low glycogen or carbohydrate availability to enhance metabolic adaptations
to the training stimulus, then replete carbohydrate to enhance their
competition performance (see Hawley et al. 2007). Currently, there is
inadequate scientific support to recommend that distance athletes should
practice carbohydrate restriction for prolonged periods Indeed, the potential
disadvantages of this practice include an increased risk of illness and injury
(see Nimmo et al., 2007) and reduced well-being or capacity to train (see
Burke and Kiens, 2006). In fact, the available study supporting a “train low”
approach (Hansen et al., 2005) achieved glycogen depletion for some, but
not all, training sessions by manipulating the training time table rather than
dietary intake. Indeed, it is likely that elite athletes spontaneously periodise
carbohydrate availability within their microcycles of training because the
practicalities of their lifestyle and training mean that some sessions are taken
after an overnight fast, or without complete refuelling between workouts.
Unless more sophisticated research can identify benefits from deliberately
“training low”, distance athletes should eat to promote carbohydrate
availability, at least for the most important training sessions of the week.
Recent recommendations for daily carbohydrate intake (Burke et al., 2004)
acknowledge that fuel requirements for distance athletes differ according to
body size and training loads. The targets of 7-10 g/kg/d for high volume
training and 5-7 g/kg/d for more moderate exercise loads provide a general
target that must be fine-tuned according to overall nutritional goals and
performance feedback from each athlete. Such recommendations may be
unfeasible for runners, particularly females, whose focus on low body mass
and body fat levels requires energy restriction and, by association, a lower
carbohydrate intake. The compromise is to periodise nutrition goals and
dietary carbohydrates intakes over the season, so that lower intakes and
physique goals are the priority of training periods, whereas greater
carbohydrate intakes are allowed during competition preparation and
recovery to maximise glycogen stores.
Although total intake of carbohydrate is probably the most important
determinant of post-exercise refuelling, during periods of high volume
training, the distance athlete should use other dietary strategies to promote
recovery. Speedy intake of carbohydrate after exercise will maximise the
period of effective refuelling time (Burke et al., 2004). Carbohydrate-rich
foods in recovery snacks and meals should be chosen according to the need
to meet practical challenges (e.g. finding portable foods when the athlete is
“on the go”) or to meet additional nutritional goals (e.g. to provide a source of
iron, protein or other nutrient need). It is probably useful to co-ingest protein
with carbohydrate-rich recovery snacks. Although the effect of protein on
glycogen resynthesis is likely to be minimal in most circumstances (see
Tipton et al. 2007), various issues of recovery and adaptation require protein
synthesis. Indeed, in addition to refuelling, the distance athlete needs to
consider a range of recovery eating goals after training and races, including
rehydration (Shirreffs et al., 2007); repair and adaptation (Hawley et al.,
2007) and preserving the immune system (Nimmo et al., 2007)
Protein requirements during training
Data from studies of essentially recreational exercisers have led to the belief
that protein requirements are not altered by any form of physical activity.
However, the high volumes of training and the training intensities possible
only in elite athletes result in estimated protein requirements that are nearly
twice that of sedentary individuals; i.e. 1.6 – 1.7 g/kg/d (Tarnopolsky et al.
1988; Friedman & Lemon, 1989). Even for modestly trained individuals,
there is an increase in protein requirements estimated from nitrogen balance
experiments (Meredith et al., 1989; Phillips et al., 1993). Although no study
has specifically calculated protein requirements for elite female athletes,
nitrogen balance data imply that requirements for women are about 25 %
less than for men; i.e. 1.2 – 1.3 g/kg/d (Phillips et al. 1993; McKenzie et al.,
2000) Most athletes will achieve these protein intakes from an everyday diet
providing 10-15% of energy as protein and adequate energy. Nevertheless,
it is important to evaluate protein intake on a g/kg basis as opposed to a
percentage of the diet to avoid low intakes that can be seen in energy
restricting athletes. A low energy intake will also negatively affect protein
requirements (Calloway, 1975).
There are benefits to the timing of nutrient delivery, especially when
undertaking high volumes of training. When female athletes consumed a
nutritional supplement immediately after each workout during a training
camp, they achieved an improvement in nitrogen balance, lesser weight loss,
and improved performance on a trial completed at the end of the week than
when the supplement was consumed after breakfast (Roy et al., 2002).
Fuelling Up for Competition
Preparation for racing should ensure that muscle carbohydrate stores are
matched to the anticipated fuel needs of the event. For races of up to 60-90
minute duration, normalised muscle glycogen stores are adequate and can
generally be achieved by 24-36 h of high carbohydrate intake. Carbohydrate
loading in preparation for prolonged exercise resulted from pioneering
studies undertaken in the 1960s using percutaneous biopsy techniques to
examine fuel utilisation and enzyme activities in the muscle. These studies
on healthy but untrained men produced the classic 7-day model to
supercompensate muscle glycogen stores; a 3-4 day depletion phase of hard
training and low carbohydrate intake followed by a 3-4-day loading phase of
high carbohydrate intake and exercise taper (Bergstrom et al., 1967). Early
field studies of prolonged running events showed that this strategy enhanced
sport performance, not by allowing the athlete to run faster but by prolonging
the time that race pace could be maintained (Karlsson and Saltin, 1971).
A modified version of carbohydrate-loading was developed when well-trained
runners were shown to super-compensate their glycogen stores without a
severe depletion or glycogen stripping phase (Sherman et al., 1981). The
modified protocol, consisting simply of 3 d of high carbohydrate intake and
taper, was offered as a more practical competition preparation which avoided
the fatigue and complexity of the extreme diet and training requirements of
the previous depletion phase. More recently, muscle glycogen
concentrations were measured after 1 and 3 days of rest and a high
carbohydrate intake (10 g/kg body mass per day) in well-trained male
athletes (Bussau et al., 2002): this study found that optimal refuelling is
probably achieved within 36 to 48 h following the last exercise session, at
least when the athlete rests and consumes adequate carbohydrate.
Theoretically, carbohydrate loading can enhance performance in distance
races that would otherwise be limited by the fatigue caused by glycogen
depletion. Studies in well-trained runners have failed to detect benefits of
carbohydrate loading for 10 km treadmill running (Pitsiladis et al., 1996), a
20.9 km race on an indoor track (Sherman et al., 1981), and a 25 km
treadmill run (Sullo et al., 1998). By contrast, carbohydrate loading has been
shown to enhance performance of a 30 km cross country run (Karlsson and
Saltin, 1971), a 30 km treadmill run in trained men (Williams et al., 1992),
and a 25 km treadmill run in moderately trained men (Sullo et al., 1998).
Typically, carbohydrate loading is associated not with an increase in overall
running speed but with maintenance of race pace during the last part of the
run compared with the control trial or group. Therefore, runners and walkers
should consider carbohydrate loading for races of 30 km and longer.
Fat adaptation – a twist on depletion prior to carbohydrate loading
Distance runners and walkers should have a high capacity for fat oxidation
during exercise as a legacy of their training. However, this capacity can be
further up-regulated by as little as 5 d of training while following a low-
carbohydrate (<2.5 g/kg/d), high-fat (~65-70% of energy) diet. In trained
individuals, “fat adaptation” achieves a markedly increased fat oxidation and
reduced utilisation of muscle glycogen (“glycogen sparing”) during
subsequent sub-maximal exercise (Burke et al., 2000). This effect persists
even when followed by acute strategies to carbohydrate load, and eat
carbohydrate before and during the bout (for review see Burke and Kiens
2006). Such a combination of dietary strategies would seem the perfect
preparation for a marathon or distance walking event, simultaneously
optimising carbohydrate stores while maximising the capacity for fat
oxidation. Curiously, the effect on endurance and ultra-endurance
performance is unclear (Burke and Kiens, 2006).
There is now evidence that what was initially viewed as glycogen sparing
may be, in fact, a down-regulation of carbohydrate metabolism or “glycogen
impairment”. Fat adaptation/ carbohydrate restoration strategies are
associated with a reduction in the activity of a key enzyme regulating
carbohydrate metabolism, pyruvate dehydrogenase (Stellingwerff et al.,
2006). Such a change would impair rates of glycogenolysis at a time when
muscle carbohydrate requirements are high. This explains the observation
that when fat adaptation/carbohydrate restoration are applied to exercise
protocols which mimic a real-life race – self-pacing, and the interspersing of
high-intensity and moderate-intensity exercise - there is a compromised
ability to performance high-intensity sprints (Havemann et al. 2006) In many
endurance events, the critical activities in a race – the breakaway, the surge
up a hill, or the sprint to the finish line – are all dependent on the runner’s
ability to work at high intensities. With growing evidence that this critical
ability may be impaired, it now seems clear that fat adaptation or pre-loading
depletion strategies should not be undertaken by distance athletes.
Fluid and Fuel Intake during races
In distance running and walking events, especially road races, a network of
aid stations allows competitors to consume fluids during the race. In large
community participation events, a supply of water, sport drinks, and sponges
is provided, although elite competitors are usually provided with opportunities
to supply their own race beverages at specially marked tables. There is still
debate on the ideal hydration plans for distance events, with the observation
that most top runners are conservative with fluid intake while some of the
“back of the pack” participants in large community events risk serious
problems from over-consumption of fluids (Noakes, 2002; Almond et al.,
2005). These issues are covered in greater detail by Shirreffs et al. (2007).
The use of carbohydrate–electrolyte drinks (sport drinks) during races of 60
min or longer provides the runner or walker with the potential to replace fluid
and carbohydrate simultaneously, with the option of altering the carbohydrate
concentration of the drink (typically 4-8 g/100 ml), according to the priority of
rehydration or refuelling in a particular event. Sports gels and confectionery
are other easily consumed sources of carbohydrate often consumed by
distance athletes. There is good evidence of the benefits of carbohydrate
intake during prolonged (>90 min) exercise (Hargreaves 1999), with reports
dating back to the Boston marathon in the 1920s that the consumption of
sweets during the race prevented hypoglycaemia and enhanced running
performance (Gordon et al. 1925; Levine et al. 1924). Recent studies in
which carbohydrate ingestion enhanced a running protocol include a 40 km
outdoor run in the heat (Millard-Stafford et al. 1992), a 30 km road run
(Tsintzas et al. 1993), a marathon run on a treadmill (Tsintzas et al. 1995)
and a ~2 h treadmill protocol to exhaustion at 70% VO2max (Tsintzas et al.
1996b). The generally accepted mechanisms of performance enhancement
include prevention of hypoglycaemia, sparing of liver glycogen, and provision
of an additional muscle fuel substrate (Hargreaves 1999). However, in the
case of running, there is some evidence of muscle glycogen sparing, at least
in selected fibres (Tsintzas et al. 1996a; Tsintzas et al. 1993).
The effect of carbohydrate intake during shorter distance events is unclear
with the potential mechanism of any performance enhancements being
attributable to effects on the central nervous system rather than provision of
muscle fuel (see Burke, 2007). One study involving a 15 km treadmill run in a
hot environment found an improvement in speed over the last, self-paced
portion of the run when carbohydrate was ingested immediately before and
during the run compared with a placebo trial (Millard-Stafford et al. 1997). By
contrast, carbohydrate intake during an 18 km run failed to enhance
performance of a large group of runners or the fastest runners in the group
compared with water (van Nieuwenhoven et al. 2005), and highly trained
runners experienced a trivial effect on performance when carbohydrate was
consumed during a half-marathon (Burke et al., 2005. Further studies are
needed to determine the full range of events that might benefit from
carbohydrate intake immediately before and during the race.
Sex differences in nutrition strategies
It has been assumed that dietary advice for female distance athletes would
be a simple extrapolation from male athletes, scaled to their smaller size.
However, numerous studies have found that females oxidise more fat and
less carbohydrate than men during endurance exercise (see Tarnopolsky,
2000). An early study found that increasing dietary carbohydrate intake from
55% to 75% of habitual energy intake for 4 days neither increased glycogen
storage nor enhanced cycling performance in female athletes, in stark
contrast to the results seen in males (Tarnopolsky et al., 1995). Of course,
the relatively low energy intake of the females limited carbohydrate intake to
< 6.5 g/kg/d even in the “loading” phase. A follow-up study provided an
additional trial in which 75% of a higher energy intake achieved carbohydrate
intakes > 8 g/kg/d (Tarnopolsky et al., 2001). With higher carbohydrate and
extra energy, females increased muscle glycogen, albeit to levels which were
about 50% of the increase seen in male subjects. From a practical
perspective, carbohydrate loading is of use to female athletes only if they are
prepared to consume adequate energy and carbohydrate.
In contrast to the limited ability for women to carbohydrate load, the dietary
recommendations for men and women with respect to sport drink
consumption during exercise (Riddell et al., 2003; Wallis et al., 2006), and for
post-exercise glycogen re-synthesis (Tarnopolsky et al., 1997), appear to be
Sport Foods and Supplements
Many distance athletes, even at a recreational level, are consumers of sport
foods and supplements. Products such as sports drinks and liquid meal
supplements are specially designed to help a runner or walker meet specific
needs for energy, fluid and nutrients in situations where everyday foods are
not practical to eat, although the expense must be considered (see Burke,
2007). Nutritional ergogenic aids have generally been poorly tested or have
failed to live up to their claims when rigorous testing has been undertaken on
distance running/walking performance. The exception is caffeine, which may
enhance the performance of some runners (for review, see Graham, 2001).
Recent research has focused on the use of small doses of caffeine before
and during endurance exercise, since the benefits appear to be similar to that
achieved by larger doses of 6-9 mg/kg (see Maughan et al., 2007). Caffeine
intakes of as little as 3 mg/kg have been shown to enhance running
performance, including a worthwhile improvement of ~1% in an 8 km track
protocol (Bridge and Jones, 2006). However, runners who were provided
with very small amounts of caffeine (~ 1.3 mg/kg) during an 18 km road race
did not show a detectable improvement in performance (Van Nieuwenhoven
et al., 2005).
While bicarbonate supplementation is typically considered a strategy for
middle distance running (see Stellingwerff et al., 2007), it has been shown to
improve performance of the longer track events (e.g. 5,000 m races) (Oopik
et al., 2003; 2004). Creatine loading has become synonymous with the
enhancement of repeated sprint training or exercise bouts (see Tipton et al.,
2007) and is typically considered inappropriate for use by distance athletes.
In fact, runners recorded a slower time to complete a 6 km cross-country run
after creatine supplementation (Balsom et al, 1993), presumably due to the
accompanying increase in body mass. In spite of recent evidence that prior
creatine loading enhances the muscle’s capacity for glycogen loading or re-
synthesis (Nelson et al., 2001; van Loon et al., 2004), it is likely that the
increase in body mass would hinder performance in distance running events,
particularly if the course is hilly. Further research is needed to test the
hypothesis that glycerol hyperhydration can enhance thermoregulatory
function in conditions in which thermal stress limits running performance.
Finally, the claims made in support of the majority of other supplements and
compounds marketed as ergogenic aids are not supported by scientific
research (see Burke, 2007). Of course, more research is needed, using
rigorous control and carefully chosen protocols to test the claims for most
products. In many cases, particular (proposed) ergogenic compounds that
are used by distance athletes have not been appropriately tested and no
further comments can be made about these products. The reader is therefore
referred to the general conclusions provided by Maughan et al., 2007.
Summary of nutrition guidelines for distance athletes
Clear consensus
for Distance athletes should follow established
guidelines to meet the carbohydrate needs for their
training loads and to enhance recovery after each
training session. These strategies are particularly
important to promote performance and recovery for
key training sessions.
Distance athletes should consume sufficient
carbohydrate to prepare fuel stores that are
adequate for their event. Carbohydrate loading or
glycogen supercompensation will be of benefit to
longer events such as the marathon or 50 km walk.
A prolonged depletion phase is unnecessary and
may even impair performance.
Carbohydrate and fluid intake during an event is
possible and of probable value for races lasting
longer than 60 minutes. Each athlete should
experiment to find a plan that is practical and
provides benefits for their performance.
Iron deficiency may be a problem for some distance
runners, but this is a diagnosis of exclusion and
other causes need to be ruled out. Nutritional
counseling to increase intake of bioavailable iron is
an important goal of prevention and therapy.
Some sports supplements such as sports drinks and
liquid meals may be useful in providing a practical
way for distance athletes to meet their nutrition
goals. Moderate doses of caffeine can provide an
ergogenic benefit to distance running and may be
useful for some runners.
Clear consensus
against Distance athletes should not practise extreme levels
of energy restriction to achieve loss of body
weight/body fat without considering the effect on
their ability to meet goals for carbohydrate, protein,
iron or other nutrients. Hormonal balance, bone
health and the immune system are also critically
impaired by inadequate energy intakes.
Routine supplementation with iron or iron injections
in the belief that it enhances performance should be
strongly discouraged in the absence of documented
iron depletion or anaemia. Supplementation in the
absence of deficiency can lead to serious medical
conditions such as haemosiderosis.
The majority of supplements that are promoted to
distance athletes are unlikely to provide substantial
benefits, and should not replace sound eating and
training practices.
Issues that are
equivocal It is unclear whether distance athletes will enhance
adaptations and performance outcomes by
undertaking deliberate strategies to restrict
carbohydrate availability during training. In the real
world, elite athletes will probably achieve some level
of periodisation of carbohydrate status within the
microcycles of their training program. Any benefits
of more prolonged carbohydrate depletion need to
be balanced by the possible disadvantages.
Achten, J., Halson, S. H., Moseley, L., Rayson, M. P., Casey, A. and
Jeukendrup, A. E. (2004). Higher dietary carbohydrate content during
intensified running training results in better maintenance of performance and
mood state. Journal of Applied Physiology, 96, 1331-1340.
Almond, C. S. D., Shin, A. Y., Fortescue, E. B., Mannix, R. C., Wypij, D.,
Binstadt, B. A., Duncan, C. N., Olson, D. P., Salerno, A. E., Newburger, J. W.
and Greenes, D. S. (2005). Hyponatremia among runners in the Boston
marathon. New England Journal of Medicine, 352, 1550-1556.
Ashenden, M. J., Fricker, P. A., Ryan, R. K., Morrison, N. K., Dobson, G. P.
and Hahn, A. G. (1998). The haematological response to an iron injection
amongst female athletes. International Journal of Sports Medicine, 19, 474-
Asp, S., Rohde, T. and Richter, E. A. (1997). Impaired muscle glycogen
resynthesis after a marathon is not caused by decreased muscle GLUT-4
content. Journal of Applied Physiology, 83, 1482-1485.
Balsom, P. D., Harridge, S. D. R., Soderlund, K., Sjodin, B. and Ekblom, B.
(1993). Creatine supplementation per se does not enhance endurance
exercise performance. Acta Physiologica Scandinavica, 149, 521-523.
Bergstrom, J., L. Hermansen, E. Hultman and B. Saltin. 1967. Diet, muscle
glycogen and physical performance. Acta Physiologica Scandinavica 71:
Billat, V., Lepretre, P. M., Heugas, A. M., Laurence, M. H., Salim, D., and
Koralsztein, J. P. (2003). Training and bioenergetic characteristics in elite
male and female Kenyan runners. Medicine and Science in Sports and
Exercise, 35, 297-304; discussion 305-296.
Blom, C. S. B., Costill, D. L. and Vollestad, N. K. (1987). Exhaustive running:
inappropriate as a stimulus of muscle glycogen supercompensation.
Medicine and Science in Sports and Exercise, 19, 398-403.
Bridge, C. A. and Jones, M. A. (2006). The effect of caffeine ingestion on 8
km run performance in a field setting. Journal of Sports Sciences, 24, 433-
Brownlie, T., Utermohlen, V., Hinton, P. S. and Haas, J. D. (2004). Tissue
iron deficiency without anemia impairs adaptations in endurance capacity
after aerobic training in previously untrained women. American Journal of
Clinical Nutrition, 79, 427-443.
Burke, L. M., Angus, D. J., Cox, G. R., Cummings, N. K., Febbraio, M. A.,
Gawthorn, K., Hawley, J. A., Minehan, M., Martin, D. T. and Hargreaves, M.
(2000). Effect of fat adaptation and carbohydrate restoration on metabolism
and performance during prolonged cycling. Journal of Applied Physiology,
89, 2413-2421.
Burke, L. M., Kiens, B. and Ivy, J. L. (2004). Carbohydrates and fat for
training and recovery. Journal of Sports Sciences, 22, 15-30.
Burke, L. M., Wood, C., Pyne, D. B., Telford, R. D. and Saunders, P. U.
(2005). Effect of carbohydrate intake on half-marathon performance of well-
trained runners. International Journal of Sport Nutrition and Exercise
Metabolism, 15, 573-589.
Burke, L. M. and Kiens, B. (2006). "Fat adaptation" for athletic performance -
the nail in the coffin? Journal of Applied Physiology, 100, 7-8.
Burke, L.M. (2007). Middle- and long-distance running. In Practical Sports
Nutrition, pp. 109-140. Champaign, Illinois, Human Kinetics.
Bussau, V. A., Fairchild, T. J., Rao, A., Steele, P. D. and Fournier, P. A.
(2002). Carbohydrate loading in human muscle: an improved 1 day protocol.
European Journal of Applied Physiology, 87, 290-295.
Calloway DH. (1975). Nitrogen balance of men with marginal intakes of
protein and energy. Journal of Nutrition 105, 914-923.
Deakin, V. (2006). Iron depletion in athletes. In: Clinical Sports Nutrition, 3rd
edition (edited by L. Burke & V. Deakin), pp. 263-312, Sydney: McGraw-Hill.
Dennis, S. C. and Noakes, T. D. (1999). Advantages of a smaller bodymass
in humans when distance-running in warm, humid conditions. European
Journal of Applied Physiology and Occupational Physiology, 79, 280-284.
Fogelholm, M. (1995). Inadequate iron status in athletes: an exaggerated
problem? In: Sports nutrition: minerals and electrolytes. (edited by C. V. Kies
& J. A. Driskell), pp. 81-95, Boca Raton: CRC Press.
Forslund AH, El-Khoury AE, Olsson RM, Sjodin AM, Hambraeus L & Young
VR. (1999). Effect of protein intake and physical activity on 24-h pattern and
rate of macronutrient utilization. American Journal of Physiology 276, E964-
Friedman JE & Lemon PW. (1989). Effect of chronic endurance exercise on
retention of dietary protein. International Journal of Sports Medicine 10, 118-
Gordon, B., Kohn, L. A., Levine, S. A., Matton, M., Scriver, W. d. and
Whiting, W. B. (1925). Sugar content of the blood in runners following a
marathon race, with especial reference to the prevention of hypoglycemia:
further observations. Journal of the American Medical Association, 85, 508-
Graham TE. (2001). Caffeine and exercise: metabolism, endurance and
performance. Sports Med 31, 785-807.
Hargreaves, M. (1999). Metabolic responses to carbohydrate ingestion:
effects on exercise performance. In: Perspectives in exercise science and
sports medicine, Vol. 12: The metabolic basis of performance in exercise and
sport (edited by D. R. Lamb & R. Murray), pp. 93-124). Carmel, In.: Cooper.
Havemann, L., West, S., Goedecke, J.H., McDonald, I.A., St-Clair Gibson,
A., Noakes, T.D., and Lambert, E.V. (2006). Fat adaptation followed by
carbohydrate-loading compromises high-intensity sprint performance.
Journal of Applied Physiology, 100, 194-202.
Hawley, J.A., Gibala, M.J., and Bermon, S. (2007). Innovations in athletic
preparation: role of substrate availability to modify training adaptation and
performance. Journal of Sports Sciences
Karlsson, J. and Saltin, B. (1971). Diet, muscle glycogen, and endurance
performance. Journal of Applied Physiology, 31, 203-206.
Klingshirn, L. A., Pate, R. R., Bourque, S. P., Davis, J. M. and Sargent, R. G.
(1992). Effect of iron supplementation on endurance capacity in iron-depleted
female runners. Medicine and Science in Sports and Exercise, 24, 819-824.
Kirwan, J. P., Costill, D. L., Mitchell, J. B., Houmard, J. A., Flynn, M. G., Fink,
W. J. and Beltz, J. D. (1988). Carbohydrate balance in competitive runners
during successive days of intense training. Journal of Applied Physiology, 65,
Lamanca, J. J. and Haymes, E. M. (1993). Effects of iron repletion on
VO2max, endurance, and blood lactate in women. Medicine and Science in
Sports and Exercise, 25, 1386-1392.
Levine, S. A., Gordon, B. and Derick, C. L. (1924). Some changes in the
chemical constituents of the blood following a marathon race, with special
reference to the development of hypoglycemia. Journal of the American
Medical Association, 82, 1778-1779.
Lucia, A., Esteve-Lanao, J., Olivan, J., Gomez-Gallego, F., San Juan, A. F.,
Santiago, C., Perez, M., Chamorro-Vina, C., and Foster, C. (2006).
Physiological characteristics of the best Eritrean runners-exceptional running
economy. Applied Physiology: Nutrition and Metabolism, 31, 530-540.
McKenzie, S., Phillips, S., Carter, S.L., Lowther, S., Gibala, M.J. and
Tarnopolsky, M.A. (2000). Endurance exercise training attenuates leucine
oxidation and branched-chain 2-oxo acid dehydrogenase activation during
exercise in humans. American Journal of Physiology, 278, E580–E587.
Manore, M.M., Kam, L.C., Loucks, A.B. (2007)l The female athlete triad:
components, nutrition issues, and health consequences. Journal of Sports
Marino, F. E., Mbambo, Z., Kortekaas, E., Wilson, G., Lambert, M. I.,
Noakes, T. D. and Dennis, S. C. (2000). Advantages of smaller body mass
during distance running in warm, humid environments. Pflugers Archives -
European Journal of Physiology, 441, 359-367.
Maughan, R.J., Depiesse, F. and Geyer, H. (2007) The use of dietary
supplements by athletes. Journal of Sports Sciences
Meredith CN, Zackin MJ, Frontera WR & Evans WJ. (1989). Dietary protein
requirements and body protein metabolism in endurance-trained men.
Journal of
Applied Physiology, 66, 2850-2856.
Meyer, F., O`Connor, H., Shirreffs, S.M. (2007). Nutrition for the young
athlete. Journal of Sports Sciences.
Millard-Stafford, M. L., Sparling, P. B., Rosskopf, L. B. and Dicarlo, L. J.
(1992). Carbohydrate-electrolyte replacement improves distance running
performance in the heat. Medicine and Science in Sports and Exercise, 24,
Millard-Stafford, M., Rosskopf, L. B., Snow, T. K. and Hinson, B. T. (1997).
Water versus carbohydrate-electrolyte ingestion before and during a 15-km
run in the heat. International Journal of Sport Nutrition, 7, 26-38.
Nelson, A. G., Arnall, D. A., Kokkonen, J., Day, R. and Evans, J. (2001).
Muscle glycogen supercompensation is enhanced by prior creatine
supplementation. Medicine and Science in Sports and Exercise, 33, 1096-
Nielsen, P. and Nachtigall, D. (1998). Iron supplementation in athletes:
current recommendations. Sports Medicine, 26, 207-216.
Nimmo, M.A., and Ekblom, B. (2007). Fatigue and illness in athletes. Journal
of Sports Sciences
Noakes, T. D. (2002). IMMDA advisory statement of guidelines for fluid
replacement during marathon running. New studies in athletics: the IAAF
technical quarterly, 17, 15-24.
O’Connor, H., Olds, T., and Maughan, R.J. 2007 Physique & performance for
track & field events. Journal of Sports Sciences
Oopik, V., Saaremets, I., Medijainen, L., Karelson, K., Janson, T. and
Timpmann, S. (2003). Effects of sodium citrate ingestion before exercise on
endurance performance in well-trained runners. British Journal of Sports
Medicine, 37, 485-489.
Oopik, V., Saaremets, I., Timpmann, S., Medijainen, L. and Karelson, K.
(2004). Effects of acute ingestion of sodium citrate on metabolism and 5 km
running performance: a field study. Canadian Journal of Applied Physiology,
29, 691-703.
Phillips, S.M., Atkinson, S.A., Tarnopolsky, M.A., and MacDougall, J.D
(1993). Gender differences in leucine kinetics and nitrogen balance in
endurance athletes. Journal of Applied Physiology, 75, 2134-2141
Pitsiladis, Y. P., Duignan, C. and Maughan, R. J. (1996). Effects of
alterations in dietary carbohydrate intake on running performance during a 10
km treadmill time trial. British Journal of Sports Medicine, 30, 226-231.
Reilly, T., Waterhouse, J., Burke, L.M., and Alonso, J.M. (2007) Nutrition for
travel. Journal of Sports Sciences
Riddell MC, Partington SL, Stupka N, Armstrong D, Rennie C & Tarnopolsky
(2003). Substrate utilization during exercise performed with and without
ingestion in female and male endurance trained athletes. International
Journal of Sport Nutrition and Exercise Metabolism 13, 407-421.
Roy BD, Luttmer K, Bosman MJ & Tarnopolsky MA. (2002). The influence of
exercise macronutrient intake on energy balance and protein metabolism in
active females participating in endurance training. International Journal of
Sport Nutrition and Exercise Metabolism 12, 172-188.
Saltin, B., Larsen, H., Terrados, N., Bangsbo, J., Bak, T., Kim, C. K.,
Svedenhag, J., and Rolf, C. J. (1995). Aerobic exercise capacity at sea level
and at altitude in Kenyan boys, junior and senior runners compared with
Scandinavian runners. Scandinavian Journal of Medicine and Science in
Sports, 5, 209-221.
Schoene, R. B., Escourrou, P., Robertson, H. T., Nilson, K. L., Parsons, J. R.
and Smith, N. J. (1983). Iron repletion decreases maximal exercise lactate
concentrations in female athletes with minimal iron-deficiency anemia.
Journal of Laboratory and Clinical Medicine, 102, 306-312.
Seiler, K. S., and Kjerland, G. O. (2006). Quantifying training intensity
distribution in elite endurance athletes: is there evidence for an "optimal"
distribution? Scandinavian Journal of Medicine and Science in Sports, 16,
Sherman, W. M., Costill, D. L., Fink, W. J. and Miller, J. M. (1981). Effect of
exercise-diet manipulation on muscle glycogen and its subsequent utilisation
during performance. International Journal of Sports Medicine, 2, 114-118.
Sherman, W. M., Costill, D. L., Fink, W. J., Hagerman, F. C., Armstrong, L. E.
and Murray, T. F. (1983). Effect of a 42.2 km footrace and subsequent rest or
exercise on muscle glycogen and enzymes. Journal of Applied Physiology,
55, 1219-1224.
Sherman, W. M., Doyle, J. A., Lamb, D. R. and Strauss, R. H. (1993). Dietary
carbohydrate, muscle glycogen, and exercise performance during 7 d of
training. American Journal of Clinical Nutrition, 57, 27-31.
Shirreffs, S.M., Casa, D.J., Carter, R. 2007. Fluid needs for training and
competition in athletics. Journal of Sports Sciences
Sullo, A., Monda, A., Brizzi, G., Meninno, V., Papa, A., Lombardo, P. and
Fabbri, B. (1998). The effect of a carbohydrate loading on running
performance during a 25-km treadmill time trial by level of aerobic capacity.
European Review for Medical and Pharmacological Sciences, 2, 195-202.
Tarnopolsky MA. (2000). Gender differences in substrate metabolism during
endurance exercise. Canadian Journal of Applied Physiology 25, 312-327.
Tarnopolsky MA, Atkinson SA, Phillips SM & MacDougall JD. (1995).
loading and metabolism during exercise in men and women. Journal of
Applied Physiology 78, 1360-1368.
Tarnopolsky MA, Bosman M, Macdonald JR, Vandeputte D, Martin J & Roy
(1997). Postexercise protein-carbohydrate and carbohydrate supplements
muscle glycogen in men and women. Journal of Applied Physiology 83,
Tarnopolsky MA, MacDougall JD & Atkinson SA. (1988). Influence of protein
and training status on nitrogen balance and lean body mass. Journal of
Applied Physiology 64, 187-193.
Tarnopolsky MA, Zawada C, Richmond LB, Carter S, Shearer J, Graham T &
SM. (2001). Gender differences in carbohydrate loading are related to energy
intake. Journal of Applied Physiology 91, 225-230.
Tsintzas, K., Liu, R., Williams, C., Campbell, I. and Gaitanos, G. (1993). The
effect of carbohydrate ingestion on performance during a 30 km race.
International Journal of Sport Nutrition, 3, 127-139.
Tsintzas, O. K., Williams, C., Singh, R. and Wilson, W. (1995). Influence of
carbohydrate-electrolyte drinks on marathon running performance. European
Journal of Applied Physiology and Occupational Physiology, 70, 154-160.
Tsintzas, O. K., Williams, C., Boobis, L. and Greenhaff, P. (1996a).
Carbohydrate ingestion and single muscle fiber glycogen metabolism during
prolonged running in men. Journal of Applied Physiology, 81, 801-809.
Tsintzas, O. K., Williams, C., Wilson, W. and Burrin, J. (1996b). Influence of
carbohydrate supplementation early in exercise on endurance running
capacity. Medicine and Science in Sports and Exercise, 28, 1373-1379
van Loon, L. J. C., Murphy, R., Oosterlaar, A. M., Cameron-Smith, D.,
Hargreaves, M., Wagenmakers, A. J. M. and Snow, R. (2004). Creatine
supplementation increases glycogen storage but not GLUT-4 expression in
human skeletal muscle. Clinical Science, 106, 99-106.
Van Nieuwenhoven, M. A., Brouns, F. and Kovacs, E. M. R. (2005). The
effect of two sports drinks and water on GI complaints and performance
during an 18-km run. International Journal of Sports Medicine, 26, 281-285.
Wallis GA, Dawson R, Achten J, Webber J & Jeukendrup AE. (2006).
response to carbohydrate ingestion during exercise in males and females.
American Journal of Physiology 290, E708-715.
Williams, C., Brewer, J. and Walker, M. (1992). The effect of a high
carbohydrate diet on running performance during a 30-km treadmill time trial.
European Journal of Applied Physiology and Occupational Physiology, 65,
... Uma recente revisão sistemática demonstrou o efeito benéfico do uso de carboidrato previamente à prova em ciclistas treinados (Pochmuller, Schwingshackl, Colombani, & Hoffmann, 2016). Ainda, revisões narrativas prévias indicam o uso do carregamento de carboidratos para potencializar os estoques de glicogênio (Burke, Millet, & Tarnopolsky, 2017), sendo esta estratégia menos sensível em mulheres (Deldicque, & Francaux, 2015). Assim, o uso da manipulação dietética pode ser um bom recurso para promover o maior estoque de energia, resultando na manutenção e/ou melhoria no desempenho. ...
... Por essa razão, há décadas o carregamento de carboidratos é utilizado por muitos praticantes de endurance. Todavia, não observamos estudos de revisão sistemática sobre esta temática, ficando as orientações sobre esta estratégia restritas a estudos de revisão narrativa (Burke et al., 2017;Deldicque, & Francaux, 2015 #2 Add Search ("carbohydrate loading" OR "supercompensation" OR "carbohydrate supplementation" ...
... Esta revisão sistemática foi realizada com intuito de verificar os efeitos do carregamento de carboidratos no metabolismo e no desempenho de endurance. Observamos que ainda existem divergências quanto ao uso desta técnica e a melhora do desempenho de atletas (Burke et al., 2017;Ivy, Res, Sprague, & Widzer, 2003). Vale ressaltar que os estudos in- (Andrews et al., 2003;Geji et al., 2017). ...
Full-text available
Objetivo: Analisar o efeito do uso do carregamento de carboidratos no desempenho de endurance por meio de uma revisão sistemática. Metodologia: A busca foi realizada nas bases de dados PubMed/MEDLINE, Scielo e Lilacs, utilizando os termos carregamento de carboidratos e desempenho na prática de exercícios de endurance. Os estudos selecionados foram submetidos à avaliação da qualidade metodológica (Escala de PEDro), obtendo o escore igual ou maior a seis pontos. Resultados: Foram encontrados 3296 artigos, dos quais dez atingiram os critérios de inclusão. A realização dos carregamentos com doses acima de 7 g de carboidrato/kg de massa corporal/dia, por pelo menos três dias geraram melhora no desempenho, em comparação aos grupos controle/ensaio teste. Conclusão: O carregamento de carboidratos é uma boa estratégia para a melhora do desempenho em provas de endurance.
... Regarding pre-race preparation, different/various areas of intervention like training (McKelvie et al., 1985), personality (Nikolaidis et al., 2018), motivation , environmental conditions (Martin, 2007), and nutrition (Burke et al., 2007) have to be considered. Moreover, when it comes down to race performance/regarding race performance, pre-race preparation is a crucial factor/is key with its different aspects such as previous experience (Bale et al., 1986;Knechtle et al., 2011a;Salinero et al., 2017) training intensity (i.e., running speed during training) (Bale et al., 1985;McKelvie et al., 1985;Knechtle et al., 2011b;Rüst et al., 2011;Hamstra-Wright et al., 2013), training volume (i.e., running kilometers, running hours) (Bale et al., 1985(Bale et al., , 1986Yeung et al., 2001;Hamstra-Wright et al., 2013;Salinero et al., 2017;Fokkema et al., 2020), and number of training sessions (Bale et al., 1985(Bale et al., , 1986Hamstra-Wright et al., 2013). ...
Full-text available
The present study investigated pre-race preparation of a large sample of recreational runners competing in different race distances (e.g., shorter than half-marathon, half-marathon, marathon and ultra-marathon). An online questionnaire was used and a total of 3,835 participants completed the survey. Of those participants, 2,864 (75%) met the inclusion criteria and 1,628 (57%) women and 1,236 (43%) men remained after data clearance. Participants were categorized according to race distance in half-marathon (HM), and marathon/ultra-marathon (M/UM). Marathon and ultra-marathon data were pooled since the marathon distance is included in an ultra-marathon. The most important findings were (i) marathon and ultra-marathon runners were more likely to seek advice from a professional trainer, and (ii) spring was most commonly reported across all subgroups as the planned season for racing, (iii) training volume increased with increasing race distance, and (iv) male runners invested more time in training compared to female runners. In summary, runners competing in different race distances prepare differently for their planned race. Clinical Trial Registration: , identifier ISRCTN73074080. Retrospectively registered 12th June 2015.
... The decision on how much carbohydrates an athlete should consume depends upon the type of exercise in which the athlete participates and time of the season. Athletes change the intensity of their training to ensure appropriate glycogen storage (Burke et al., 2007). It may be very difficult to apply all nutrition recommendations, especially when we take into consideration the glycogen depletion exercise since most athletes taper their exercise routinely before the big competition. ...
Full-text available
Background: During competition season, races and games can be scheduled multiple times a week or even within 24 hours. This may interfere with macronutrient periodization, carbohydrate loading regimen, hydration status and nutrition. Most of the studies investigating the influence of diet on performance do not take into consideration that an athlete may need to perform closely spaced, repeated events. The study tested whether the fat-adaptation diet would improve performance on the consecutive day of interval exercise. Methods: Nine healthy, male amateur athletes were randomly assigned to two diets in a single-blinded, crossover study. The fat-adaptation diet consisted of the first five days high-fat diet (2.62 g/kg/d carbohydrates, 2.23 g/kg/d fat). The day six and seven of the fat-adaptation diet consisted of 5.42 g/kg/d carbohydrates. The balanced carbohydrate diet consisted of a seven-day protocol involving consumption of 5.33 g/kg/d. On day seven of each diet protocol, subjects performed an interval treadmill test dependent on exhaustion. Blood glucose and lactate were measured before and immediately after exercise. The identical treadmill test was performed once again after 24 hours on the day eight of each diet. Results: There was a significant decrease in the total distance to exhaustion after the fat-adaptation diet (11.2 ±0.6 km vs 10.9 ±0.8 km), p < 0.05 with lactate being lower after exercise on the second day (6.2 ±0.8 mM) compared to the first day (7.4 ±0.9 mM). Glucose was elevated after exercise except on the second test day on the fat-adaptation diet (5.3 ±0.3 mmol/L). Conclusions: Athletes perform better on the balanced carbohydrate diet than short fat-adaptation diet on the consecutive day of interval test.
... The decision on how much carbohydrates an athlete should consume depends upon the type of exercise in which the athlete participates and time of the season. Athletes change the intensity of their training to ensure appropriate glycogen storage (Burke et al., 2007). It may be very difficult to apply all nutrition recommendations, especially when we take into consideration the glycogen depletion exercise since most athletes taper their exercise routinely before the big competition. ...
Full-text available
Background. During competition season, races and games can be scheduled multiple times a week or even within 24 hours. This may interfere with macronutrient periodization, carbohydrate loading regimen, hydration status and nutrition. Most of the studies investigating the influence of diet on performance do not take into consideration that an athlete may need to perform closely spaced, repeated events. The study tested whether the fat-adaptation diet would improve performance on the consecutive day of interval exercise. Methods. Nine healthy, male amateur athletes were randomly assigned to two diets in a single-blinded, cross-over study. The fat-adaptation diet consisted of the first five days high-fat diet (2.62 g/kg/d carbohydrates, 2.23 g/kg/d fat). The day six and seven of the fat-adaptation diet consisted of 5.42 g/kg/d carbohydrates. The balanced carbohydrate diet consisted of a seven-day protocol involving consumption of 5.33 g/kg/d. On day seven of each diet protocol, subjects performed an interval treadmill test dependent on exhaustion. Blood glucose and lactate were measured before and immediately after exercise. The identical treadmill test was performed once again after 24 hours on the day eight of each diet. Results. There was a significant decrease in the total distance to exhaustion after the fat-adaptation diet (11.2 ±0.6 km vs 10.9 ±0.8 km), p < 0.05 with lactate being lower after exercise on the second day (6.2 ±0.8 mM) compared to the first day (7.4 ±0.9 mM). Glucose was elevated after exercise except on the second test day on the fat-adaptation diet (5.3 ±0.3 mmol/L). Conclusions. Athletes perform better on the balanced carbohydrate diet than short fat-adaptation diet on the consecutive day of interval test.
... It is not clear if this is due to fewer symptoms which leads to an increase in intake. In addition, there was no difference between genders [28,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]. ...
Full-text available
The ultramarathon is defined as an event whose distance is greater than a marathon. It requires not only a preparation on the endurance performance, but also of other more specific qualities such as orientation and climbing. This type of event has a minimum duration of 5 h up to 22 consecutive days or more. These characteristics influence in the preponderance of the energy system and consequently which nutrients will be necessary to intake and increase in order to replace them. The adequate nutritional planning is a fundamental tool to optimize the athlete’s performance, replenishing nutrients and electrolytes and reducing fatigue during exercise The aim of the review is to determine dietary guidelines in continuous ultramarathons. The energy, macronutrient, vitamin, and mineral requirements will be increased according to the intensity and duration of the ultramarathon. The energy expenditure ranges from 350-650 kcal/h, determining a negative balance. The role of carbohydrates for its rapid energy replenishment and the role of lipids for multi-day events are distinguished. The recommendation of carbohydrates is 7-12 g/kg in order to achieve muscle glycogen repletion. Protein intake is 1.2-1.7 g/kg to prevent muscle damage and/or used it as an energy source in case of a poor energy supply. Hydration is crucial in prolonged events and especially in warm environments. Once the systematic review of nutritional guidelines in continuous ultra-marathon events has been performed, it has been found that athletes fail to meet nutritional and water recommendations. The cause of this fact is multifactorial (e.g., high energy depletions, inability to carry the totality of food with them, tiredness of the same flavors, hot environmental conditions..), but mainly due to gastrointestinal discomfort and lack of appetite. It is important to provide runners with not only accurate nutritional guidelines, but the correct way to accomplish them to finish the event and to prevent episodes that compromise their health.
PURPOSE: This study aimed to explore the direction of nutrition management and education for adolescent athletes based on the transtheoretical model (TTM).METHODS: This cross-sectional study was conducted on 205 male adolescent athletes using questionnaires in Seoul and Gyeonggi provinces. Differences in nutritional indices, dietary behaviors, and dietary self-efficacies were compared according to the stage of dietary behavior change, and significance was verified using analysis of variance and chi-square tests.RESULTS: According to the stage of change in dietary behavior, a significant difference was observed in the grade and score of the nutrition quotient (NQ), and the nutritional status and quality of meals were extremely poor in the precontemplation and contemplation groups. Dietary self-efficacy differed significantly according to the stage of change in dietary behavior. Compared to the pre-contemplation and contemplation stage groups, the action and maintenance stage groups had a higher willingness to practice desirable dietary behaviors and overcome barriers.CONCLUSIONS: In this study, we demonstrated that individualized nutritional intervention based on TTM was an effective strategy for healthy dietary behavior and had a positive impact on adolescent athletes’ sports performance. Furthermore, nutrition education should include content that enhances students’ dietary self-efficacy.
Full-text available
Purpose: To determine body composition, energy availability, training load, and menstrual status in young elite endurance running athletes (ATH) over 1 year, and in a secondary analysis, to investigate how these factors differ between nonrunning controls (CON), and amenorrheic (AME) and eumenorrheic (EUM) ATH. Correlations to injury, illness, and performance were also examined. Methods: Altogether 13 ATH and 8 CON completed the Low Energy Availability in Females Questionnaire. Anthropometric, energy intake, and peak oxygen uptake assessments were made at 4 time points throughout the year: at baseline post competition season, post general preparation, post specific preparation, and post competition season the following year. Logs of physical activity, menstrual cycle, illness, and injury were kept by all participants. Performance was defined using the highest International Association of Athletics Federations points prior to and after the study. Results: ATH had significantly lower body mass (P < .008), fat percentage (P < .001), and body mass index (P < .027) compared with CON, while energy availability did not differ between ATH and CON. The Low Energy Availability in Females Questionnaire score was higher in ATH than in CON (P < .028), and 8 ATH (vs zero CON) were AME. The AME had significantly more injury days (P < .041) and ran less (P < .046) than EUM, while total annual running distance was positively related to changes in performance in ATH (r < .62, P < .043, n < 11). Conclusions: More than half of this group of runners was AME, and they were injured more and ran less than their EUM counterparts. Furthermore, only the EUM runners increased their performance over the course of the year.
Full-text available
Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also ben shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit.
Full-text available
There is still debate in the literature on whether or not endurance athletes tend to have low iron stores. In this article, we propose that endurance athletes really are at risk of becoming iron deficient due to an imbalance between absorption of dietary iron and exercise-induced iron loss. The purpose of this article is to present a critical review of the literature on iron supplementation in sport. The effect of iron deficiency on performance, its diagnosis and suggestions for treatment are also discussed. Studies of the nutritional status of athletes in various disciplines have shown that male, but not female, athletes clearly achieve the recommended dietary intake of iron (10 to 15 mg/day). This reflects the situation in the general population, with menstruating women being the main risk group for mild iron deficiency, even in developed countries. Whereas the benefit of iron supplementation in athletes with iron deficiency anaemia is well established, this is apparently not true for non-anaemic athletes who have exhausted iron stores alone (prelatent iron deficiency); most of the studies in the literature show no significant changes due to supplementation in the physical capacity of athletes with prelatent iron deficiency. However, the treatment protocols used in some of these studies do not meet the general recommendations for the optimal clinical management of iron deficiency, that is, with respect to adequate daily dosage, mode of administration and treatment period. For future studies, we recommend a prolonged treatment period (≥3 months) with standardised conditions of administration (use of a pharmaceutical iron preparation with known high bioavailability and a dosage of ferrous (Fe++) iron 100 mg/day, taken on an empty stomach). Currently, decisions regarding iron supplementation are best made on the basis of taking care of individual athletes. We believe that there are sufficient arguments to support controlled iron supplementation in all athletes with low serum ferritin levels. Firstly, the development of iron deficiency is prevented. Secondly, the nonspecific upregulation of intestinal metal ion absorption is reverted to normal, thus limiting the hyperabsorption of potentially toxic lead and cadmium even in individuals with mild iron deficiency.
Full-text available
The aim of the present study was to examine the influence of a high carbohydrate diet and the level of aerobic capacity on running performance during a 25-km treadmill time trial. The study used a 2*2 design with the factors being training and diet composition. We divided the athletes in 4 groups: 1. Trained athletes with carbohydrate loading (CHO1); 2. Trained athletes without carbohydrate loading (C1); 3. Untrained athletes with carbohydrate loading (CHO2); 4. Untrained athletes without carbohydrate loading (C2). The carbohydrate loading was effected with confectionery. Performance time, running speed, blood glucose and blood lactate concentrations were evaluated during two 25-km treadmill time trial (trial 1 and trial 2) separated by 7 days in which two groups (CHO1 and CHO2) had a carbohydrate loading. The results showed that the athletes with lower level of aerobic capacity had better performance time after carbohydrate loading. They ran faster and had a higher glucose and lactate concentrations in the last 5 km during trial 2. There were no significant differences in the other groups. In conclusion, we can assert that dietary carbohydrate loading can improve running performance and that confectionery can be used as an effective means of supplementing the normal carbohydrate intake in preparation for endurance competitions. But the improvement depends on some factors such as the distance and the level of aerobic capacity.
Full-text available
The purpose of this study was to examine the extent to which lighter runners might be more advantaged than larger, heavier runners during prolonged running in warm humid conditions. Sixteen highly trained runners with a range of body masses (55-90 kg) ran on a motorised treadmill on three separate occasions at 15, 25 or 35C, 60% relative humidity and 15 kmh-1 wind speed. The protocol consisted of a 30-min run at 70% peak treadmill running speed (sub-max) followed by a self-paced 8-km performance run. At the end of the sub-max and 8-km run, rectal temperature was higher at 35C (39.5&#450.4C, P<0.05) compared with 15C (38.6&#450.4C) and 25C (39.1&#450.4C) conditions. Time to complete the 8-km run at 35C was 30.4&#452.9 min (P<0.05) compared with 27.0&#451.5 min at 15C and 27.4&#451.5 min at 25C. Heat storage determined from rectal and mean skin temperatures was positively correlated with body mass (r=0.74, P<0.0008) at 35C but only moderately correlated at 25C (r=0.50, P<0.04), whereas no correlation was evident at 15C. Potential evaporation estimated from sweat rates was positively associated with body mass (r=0.71, P<0.002) at 35C. In addition, the decreased rate of heat production and mean running speed during the 8-km performance run were significantly correlated with body mass (r=-0.61, P<0.02 and r=-0.77, P<0.0004, respectively). It is concluded that, compared to heavier runners, those with a lower body mass have a distinct thermal advantage when running in conditions in which heat-dissipation mechanisms are at their limit. Lighter runners produce and store less heat at the same running speed; hence they can run faster or further before reaching a limiting rectal temperature.
Last year we 1 studied a group of runners who participated in the American marathon race of 25 miles, which takes place annually in Boston, April 19. In general, it was found that men who had been doing long distance running for many years did not develop hypertrophy of the heart as indicated by roentgen-ray examination. Furthermore, directly after the race, the heart was found to be somewhat contracted rather than dilated. The vital capacity of the lungs was measured and did not seem to bear any particular relation to the running ability of the contestants, and on the average it was not increased over the normal figure for men who live comparatively nonathletic lives.This year the usual distance of 25 miles was extended to 26 miles and 385 yards, the occasion being the final Olympic tryout. The examinations this year were made to see what changes occurred in
Last year the chemical examination1 of the blood of a group of runners who participated in the American marathon race held in Boston, April 19, showed that the sugar content of the blood at the finish of the race was moderately diminished in two runners and markedly diminished in four. There was, furthermore, a close correlation between the physical condition of the runner at the finish of the race and the level of the blood sugar. It was found that those competitors who had extremely low blood sugars presented a picture of shock not unlike that produced by an overdose of insulin. In making the report, it was suggested that the adequate ingestion of carbohydrate before and during any prolonged and vigorous muscular effort might be of considerable benefit in preventing the hypoglycemia and the accompanying development of symptoms of exhaustion.2In preparation for the next annual race,
Using a 65-kg athlete running a 2 h 10 min marathon as an example, we estimated that imbalances between approximately 1400 W of heat production and dissipation would occur in ambient temperatures of 17°C at 90% relative humidity (rh) to 37°C at 50% rh. Because heat production during running depends on body mass and heat loss depends on surface area, intercepts between predicted heat production and maximal heat loss with increasing speeds depend on an athlete's body mass. At 35°C and 60% rh, a 45-kg athlete could maintain thermal balance by running a 2 h 13 min marathon at 19.1 km · h−1 but a 75-kg athlete would only be able run a 3 h 28 min marathon at 12.2 km · h−1. In both cases, the production of 970–1020 W of heat would necessitate the evaporation of at least 1.5–1.6 l of sweat per hour. A lower metabolic heat production in lighter runners at any given speed may be one reason why smallness of stature is an asset in distance running.