Article

Energy intake, nonexercise physical activity, and weight loss in responders and nonresponders: The Midwest Exercise Trial 2

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Abstract

To compare energy intake, total daily energy expenditure (TDEE), nonexercise energy expenditure (NEEx), resting metabolic rate (RMR), nonexercise physical activity (NEPA), and sedentary time between participants with weight loss <5% (nonresponders) vs. ≥5% (responders) in response to exercise. Adults (18-30 years) with overweight/obesity (BMI 25-40 kg/m(2) ) were randomized to exercise: 5 days/week, 400 or 600 kcal/session, 10 months. Of the participants, 40 responded and 34 did not respond to the exercise protocol. Nonresponder energy intake was higher vs. responders, significant only in men (P=0.034). TDEE increased only in responders (P=0.001). NEEx increased in responders and decreased in nonresponders, significant only in men (P=0.045). There were no within- or between-group differences for change in RMR. NEPA increased in responders and decreased in nonresponders (group-by-time interactions: total sample, P=0.049; men, P=0.016). Sedentary time decreased in both groups, significant only in men. Men who did not lose weight in response to exercise (<5%) had higher energy intake and lower NEEx when compared with men losing ≥5%. No significant differences in any parameters assessed were observed between women who lost <5% vs. those losing ≥5%. Factors associated with the weight loss response to exercise in women warrant additional investigation. © 2015 The Obesity Society.

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... Individual responses to an exercise intervention are highly variable, but are often hidden by the reporting of typical descriptive statistics (i.e. mean and standard deviation) [1][2][3][4]. In response to the same dose of exercise, some individuals may lose large amounts of weight while others may not, or even gain weight [4][5][6]. ...
... mean and standard deviation) [1][2][3][4]. In response to the same dose of exercise, some individuals may lose large amounts of weight while others may not, or even gain weight [4][5][6]. Maximal aerobic power (VO 2 max) [7,8], resting metabolic rate (RMR) [4,9], and body composition [4,7] also exhibit high levels of variation in response to exercise training. ...
... In response to the same dose of exercise, some individuals may lose large amounts of weight while others may not, or even gain weight [4][5][6]. Maximal aerobic power (VO 2 max) [7,8], resting metabolic rate (RMR) [4,9], and body composition [4,7] also exhibit high levels of variation in response to exercise training. ...
Article
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Background Many individuals lose less weight than expected in response to exercise interventions when considering the increased energy expenditure of exercise (ExEE). This is due to energy compensation in response to ExEE, which may include increases in energy intake (EI) and decreases in non-exercise physical activity (NEPA). We examined the degree of energy compensation in healthy young men and women in response to interval training. Methods Data were examined from a prior study in which 24 participants (mean age, BMI, & VO2max = 28 yrs, 27.7 kg•m⁻², and 32 mL∙kg⁻¹∙min⁻¹) completed either 4 weeks of sprint-interval training or high-intensity interval training. Energy compensation was calculated from changes in body composition (air displacement plethysmography) and exercise energy expenditure was calculated from mean heart rate based on the heart rate-VO2 relationship. Differences between high (≥ 100%) and low (< 100%) levels of energy compensation were assessed. Linear regressions were utilized to determine associations between energy compensation and ΔVO2max, ΔEI, ΔNEPA, and Δresting metabolic rate. Results Very large individual differences in energy compensation were noted. In comparison to individuals with low levels of compensation, individuals with high levels of energy compensation gained fat mass, lost fat-free mass, and had lower change scores for VO2max and NEPA. Linear regression results indicated that lower levels of energy compensation were associated with increases in ΔVO2max (p < 0.001) and ΔNEPA (p < 0.001). Conclusions Considerable variation exists in response to short-term, low dose interval training. In agreement with prior work, increases in ΔVO2max and ΔNEPA were associated with lower energy compensation. Future studies should focus on identifying if a dose-response relationship for energy compensation exists in response to interval training, and what underlying mechanisms and participant traits contribute to the large variation between individuals.
... Exercise training when prescribed and completed at a sufficient magnitude has been shown to provide clinically meaningful weight loss that is similar to programs including energy restriction and intensive behavioral counseling; however, individual differences in weight loss are typically observed [7][8][9][10]. Other research has argued that the variability in response among individuals following an exercise training intervention can be explained by (1) decreased non-exercise activity thermogenesis (NEAT; reflecting changes in activity-related energy expenditure such as fidgeting or postural changes) or non-exercise PA (NEPA; reflecting changes in ambulatory PA) [11,12]; (2) increased dietary intake [13]; or (3) decreased resting energy expenditure [14,15]. Because PA is the most variable component of total energy expenditure, one of the potential reasons many individuals are unsuccessful when attempting to lose weight may be the dynamic change in NEPA that occurs following exercise training to maintain total energy expenditure within a narrow physiological range [15,16]. ...
... A weighted average change in NEPA was calculated from two publications that presented separate data for training and non-training days [33,34]. A subgroup analysis of data collected from the same study appeared in two publications, with the control group from the original publication [37] used to calculate each effect for training data presented in the secondary analysis [12]. Each effect was weighted by the inverse variance [38]. ...
... Multi-level linear regression was used according to standard procedures to adjust for between-study variance and the correlation between effects nested within studies [41,42]. This was required because multiple effects were gathered from studies involving repeated measures [23,43], multiple intervention groups [23,37,[44][45][46][47], or reporting subgroup comparisons in addition to the mean change [12,37]. The data analysis for the multi-level model was performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA). ...
Article
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Background Many overweight and obese individuals use exercise when attempting to lose weight. However, the improvements in weight and body composition are often far less than expected. Levels of physical activity outside of the structured exercise program are believed to change and may be responsible for the unsuccessful weight loss. Objective The purpose of this meta-analysis was to provide a quantitative estimate of the change in non-exercise physical activity (NEPA) during exercise interventions. Methods All studies included in the meta-analysis were peer-reviewed and published in English. Participants were randomized to a non-exercise comparison group or exercise training group with an intervention lasting ≥2 weeks. NEPA was measured at baseline and at various times during the study. Hedges’ d effect size (ES) was used to adjust for small sample bias, and random-effects models were used to calculate the mean ES and explore potential moderators. ResultsThe cumulative results of 44 effects gathered from ten studies published between 1997 and 2015 indicated that NEPA did not change significantly during exercise training (ES = 0.02, 95% confidence interval [CI] −0.09 to 0.13; p = 0.723). Duration of the exercise session (β = −0.0039), intervention length (β = 0.0543), and an age × sex (β = −0.0005) interaction indicated that the increase in NEPA may be attenuated in older women during exercise training and during shorter exercise interventions with longer sessions (all p < 0.005). Conclusion On average, no statistically or clinically significant mean change in NEPA occurs during exercise training. However, session duration and intervention length, age, and sex should be accounted for when designing exercise programs to improve long-term sustainability and improve the likelihood of weight loss success, as the initial decrease in NEPA appears to dissipate with continued training.
... The findings of intervention studies concur with these observations. Human participants exhibit a smaller increase in DEE than expected when prescribed daily exercise levels are increased (Goran and Poehlman 1992;Wing 1999;Keytel et al. 2005;Garland et al. 2011;Dhurandhar et al. 2015;Herrmann et al. 2015;Hand et al. 2020;Willis et al. 2020). Moreover, the longer and greater the exercise intervention, the greater the estimated energy compensation exhibited (for a summary, see Pontzer 2018 and fig. 2 therein). ...
... In extremis, this downregulation could slow growth or cause the onset of disease and impairments to ovulation and reproduction (Perrigo and Bronson 1983;Lebenstedt et al. 1999;Melin et al. 2015). However, the actual contribution of changes in BMR to energy compensate for increases in AEE is far from clear (Herrmann et al. 2015). ...
... per se. In most studies where participants exhibited no change or only a marginal decrease in body mass in response to an increase in daily activity levels, they also exhibited no change in BMR (often calculated independently of body condition; Goran and Poehlman 1992;Van Etten et al. 1997;Meijer et al. 1999;Colley 2008;Colley et al. 2010;Willis et al. 2014;Herrmann et al. 2015;Riou et al. 2019;Flack et al. 2020;Hand et al. 2020). In a few studies where participants experienced no change in body mass, they exhibited a small increase in BMR (Morio et al. 1998;Withers et al. 1998;Hunter et al. 2000). ...
Article
The received wisdom on how activity affects energy expenditure is that the more activity is undertaken, the more calories will have been burned by the end of the day. Yet traditional hunter-gatherers, who lead physically hard lives, burn no more calories each day than Western populations living in labor-saving environments. Indeed, there is now a wealth of data, both for humans and other animals, demonstrating that long-term lifestyle changes involving increases in exercise or other physical activities do not result in commensurate increases in daily energy expenditure (DEE). This is because humans and other animals exhibit a degree of energy compensation at the organismal level, ameliorating some of the increases in DEE that would occur from the increased activity by decreasing the energy expended on other biological processes. And energy compensation can be sizable, reaching many hundreds of calories in humans. But the processes that are downregulated in the long-term to achieve energy compensation are far from clear, particularly in humans-we do not know how energy compensation is achieved. My review here of the literature on relevant exercise intervention studies, for both humans and other species, indicates conflict regarding the role, if any, of basal metabolic rate (BMR) or low-level activity such as fidgeting play, particularly once changes in body composition are factored out. In situations where BMR and low-level activity are not major components of energy compensation, what then drives it? I discuss how changes in mitochondrial efficiency and changes in circadian fluctuations in BMR may contribute to our understanding of energy management. Currently unexplored, these mechanisms and others may provide important insights into the mystery of how energy compensation is achieved.
... In most of these studies, it has been presumed that changes in non-exercise PAEE observed in response to exercise represent changes in PA behavior. 5,26 This conclusion can only be supported with careful measures of both the amount of PA (using objective methods such as accelerometry) and the energy cost of PA. Although PA is often measured in studies examining the effects of exercise, the energy cost of PA is rarely measured. ...
... For example, some studies have shown that exercise, particularly lower volume and intensity exercise, 10 leads to an additive increase in TDEE, suggesting that the energy budgets are regulated in an additive manner. In contrast, as described above, several studies have shown that TDEE remains either unchanged, 5 or increases less than expected, 26,28,50 suggesting that in some situations, human energy budgets are constrained by an allocation model. Moreover, results from these studies suggest that allocation may be affected by confounders such as age (older more likely to reallocate), 5 sex (males more likely to reallocate), 26 and exercise volume (allocation more likely with higher volumes). ...
... In contrast, as described above, several studies have shown that TDEE remains either unchanged, 5 or increases less than expected, 26,28,50 suggesting that in some situations, human energy budgets are constrained by an allocation model. Moreover, results from these studies suggest that allocation may be affected by confounders such as age (older more likely to reallocate), 5 sex (males more likely to reallocate), 26 and exercise volume (allocation more likely with higher volumes). 28 Finally, there is even evidence for a performance model in humans. ...
Article
It is widely assumed that structured exercise causes an additive increase in physical activity energy expenditure (PAEE) and total daily energy expenditure (TDEE). However, the common observation that exercise often leads to a less than expected decrease in body weight, without changes in energy intake, suggests that some compensatory behavioral adaptations occur. A small number of human studies have shown that adoption of structured exercise can lead to decreases in PAEE, which is often interpreted as a decrease in physical activity (PA) behavior. An even smaller number of studies have objectively measured PA, and with inconsistent results. In animals, high levels of imposed PA induce compensatory changes in some components of TDEE. Recent human cohort studies also provide evidence that in those at the highest levels of PA, TDEE is similar when compared to less physically active groups. The objective of this review is to summarize the effects of structured exercise training on PA, sedentary behavior, PAEE and TDEE. Using models from ecological studies in animals and observational data in humans, an alternative model of TDEE in humans is proposed. This model may serve as a framework to investigate the complex and dynamic regulation of human energy budgets.
... The findings of intervention studies concur with these observations. Human participants exhibit a smaller increase in DEE than expected when prescribed daily exercise levels are increased (Dhurandhar et al. 2015;Garland et al. 2011;Goran and Poehlman 1992;Hand et al. 2020;Herrmann et al. 2015;Keytel et al. 2005;Willis et al. 2020;Wing 1999). Moreover, the longer and greater the exercise intervention, the greater the estimated energy compensation exhibited (for a summary see Pontzer 2018; his Figure 2). ...
... In extremis, this downregulation could slow growth or cause the onset of disease and impairments to ovulation and reproduction (Lebenstedt et al. 1999;Melin et al. 2015;Perrigo and Bronson 1983). However, the actual contribution of changes in BMR to energy compensate for increases in AEE is far from clear (Herrmann et al. 2015). ...
... I find very limited evidence in the human literature of BMR decreasing in response to a chronic period of increased activity energy expenditure per se. In most studies where participants exhibited no change or only a marginal decrease in body mass in response to an increase in daily activity levels they also exhibited no change in BMR (often calculated independent of body condition) (Colley 2008;Colley et al. 2010;Flack et al. 2020;Goran and Poehlman 1992;Hand et al. 2020;Herrmann et al. 2015;Meijer et al. 1999;Riou et al. 2019;Van Etten et al. 1997;Willis et al. 2014). In a few studies where participants experienced no change in body mass they exhibited a small increase in BMR (Hunter et al. 2000;Morio et al. 1998;Withers et al. 1998). ...
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Full-text available
The received wisdom on how activity affects energy expenditure is that the more activity is undertaken, the more calories will have been burned by the end of the day. Yet traditional hunter-gatherers, who lead physically hard lives, burn no more calories each day than western populations living in labour-saving environments. Indeed, there is now a wealth of data, both for humans and other animals, demonstrating that long-term lifestyle changes involving increases in exercise or other physical activities do not result in commensurate increases in daily energy expenditure (DEE). This is because humans and other animals exhibit a degree of energy compensation at the organismal level, ameliorating some of the increases in DEE that would occur from the increased activity by decreasing the energy expended on other biological processes. And energy compensation can be sizable, reaching many hundreds of calories in humans. But the processes that are downregulated in the long-term to achieve energy compensation are far from clear, particularly in humans. We do not know how energy compensation is achieved. My review here of the literature on relevant exercise intervention studies, for both humans and other species, indicates conflict regarding the role that basal metabolic rate (BMR) or low level activity such as fidgeting play, if any, particularly once changes in body composition are factored out. In situations where BMR and low-level activity are not major components of energy compensation, what then drives it? I discuss how changes in mitochondrial efficiency and changes in circadian fluctuations in BMR may contribute to our understanding of energy management. Currently unexplored, these mechanisms and others may provide important insights into the mystery of how energy compensation is achieved.
... The lack of correspondence between habitual physical activity and TEE is not limited to observational studies. In controlled exercise intervention studies, human subjects often exhibit a much smaller increase in TEE than expected from the induced exercise workload (28,34,38,84). Similarly, weight loss in exercise interventions is often less than predicted from exercise workload, suggesting a smaller increase in TEE (and smaller energy imbalance) than expected (16,26,47,70,71,79). ...
... For example, a person newly enrolled in an exercise regime that adds 200 kcal/day to their daily activity workload may be observed to show an increase in TEE of Ͻ200 kcal/day, indicating some form of compensation occurred that reduced the expected metabolic impact of the exercise program. Energy compensation to increased physical activity is a common phenomenon in exercise interventions, but the degree of compensation varies among subjects and studies (16,26,28,34,38,46,70,71,79,84), leading to uncertainty in the size and regularity of the effect. Riou and colleagues (70) examined energy compensation data from 61 studies (928 subjects). ...
... However, in cases where TEE is measured (e.g., Refs. 28,34,38,84), changes in TEE often account for all or most of the observed compensation. More direct measures of TEE are needed in exercise intervention studies. ...
Article
Humans and other species adapt dynamically to changes in daily physical activity, maintaining total energy expenditure within a narrow range. Chronic exercise thus suppresses other physiological activity, including immunity, reproduction, and stress response. This exercise-induced downregulation improves health at moderate levels of physical activity but can be detrimental at extreme workloads.
... The lack of correspondence between habitual physical activity and TEE is not limited to obser- vational studies. In controlled exercise interven- tion studies, human subjects often exhibit a much smaller increase in TEE than expected from the induced exercise workload (28,34,38,84). Simi- larly, weight loss in exercise interventions is often less than predicted from exercise workload, sug- gesting a smaller increase in TEE (and smaller en- ergy imbalance) than expected (16,26,47,70,71,79). ...
... For example, a person newly enrolled in an exercise regime that adds 200 kcal/day to their daily activity workload may be observed to show an increase in TEE of 200 kcal/day, indicating some form of compensation occurred that reduced the expected metabolic impact of the exercise pro- gram. Energy compensation to increased physical activity is a common phenomenon in exercise in- terventions, but the degree of compensation varies among subjects and studies (16,26,28,34,38,46,70,71,79,84), leading to uncertainty in the size and regularity of the effect. Riou and colleagues (70) examined energy compensation data from 61 studies (928 subjects). ...
... Energy compensation is highly variable among individuals and studies, particularly over the short term (FIGURE 2), and the causes of this variability are poorly known. Some studies, and cohorts within studies, show relatively little compensation (34). My colleagues and I have suggested that in- dividuals who are extremely sedentary or have greater body fat percentage at baseline might com- pensate less, and show a greater increase in TEE with chronic exercise, due to their greater energy reserves (58,63); with greater energy reserve, the energy stress of adding daily physical activity might be minimal, and the energy compensation response blunted. ...
... Completion rate. Fourteen trials reported the percentage of exercise sessions attended as >99 (19,21) , 62·5 (26,40) , 94 (24) , 99 % for moderate intensity and 96 % for high intensity (23) , 90 % for aerobic training, 84 % for combined aerobic and resistance training, but % was not available for resistance training (31) , 100 % for 30-min and 60-80 % for 60-and 90-min groups (32) , 86 (38,48) , >90 (41) , 85 (47) , 95 (50) , 100 (45) and 64 % (26,40) , whereas one trial (36) reported the level of exercise EE (prescribed 6276 kJ/week; achieved 6000 kJ/week). Whybrow et al. (25) and Meijer et al. (46) reported good compliance, but no percent values were given. ...
... Completion rate. Fourteen trials reported the percentage of exercise sessions attended as >99 (19,21) , 62·5 (26,40) , 94 (24) , 99 % for moderate intensity and 96 % for high intensity (23) , 90 % for aerobic training, 84 % for combined aerobic and resistance training, but % was not available for resistance training (31) , 100 % for 30-min and 60-80 % for 60-and 90-min groups (32) , 86 (38,48) , >90 (41) , 85 (47) , 95 (50) , 100 (45) and 64 % (26,40) , whereas one trial (36) reported the level of exercise EE (prescribed 6276 kJ/week; achieved 6000 kJ/week). Whybrow et al. (25) and Meijer et al. (46) reported good compliance, but no percent values were given. ...
... Exercise mode. NRT included a variety of indoor or outdoor walking/running (36,38,42,46) , cycle ergometer exercise (39,45) , fitness classes and resistance training (47,48) , resistance training only (41,50) and treadmill (40) . RT intervention arms involved a combination of resistance and aerobic training (31) and daily walking (32) . ...
Article
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Non-exercise physical activity (NEPA) and/or non-exercise activity thermogenesis (NEAT) reductions may occur from diet and/or exercise-induced negative energy balance interventions, resulting in less-than-expected weight loss. This systematic review describes the effects of prescribed diet and/or physical activity (PA)/exercise on NEPA and/or NEAT in adults. Studies were identified from PubMed, web-of-knowledge, Embase, SPORTDiscus, ERIC and PsycINFO searches up to 1 March 2017. Eligibility criteria included randomised controlled trials (RCT), randomised trials (RT) and non-randomised trials (NRT); objective measures of PA and energy expenditure; data on NEPA, NEAT and spontaneous PA; ≥10 healthy male/female aged>18 years; and ≥7 d length. The trial is registered at PROSPERO-2017-CRD42017052635. In all, thirty-six articles (RCT-10, RT-9, NRT-17) with a total of seventy intervention arms (diet, exercise, combined diet/exercise), with a total of 1561 participants, were included. Compensation was observed in twenty-six out of seventy intervention arms (fifteen studies out of thirty-six reporting declines in NEAT (eight), NEPA (four) or both (three)) representing 63, 27 and 23 % of diet-only, combined diet/exercise, and exercise-only intervention arms, respectively. Weight loss observed in participants who decreased NEAT was double the weight loss found in those who did not compensate, suggesting that the energy imbalance degree may lead to energy conservation. Although these findings do not support the hypothesis that prescribed diet and/or exercise results in decreased NEAT and NEPA in healthy adults, the underpowered trial design and the lack of state-of-the-art methods may limit these conclusions. Future studies should explore the impact of weight-loss magnitude, energetic restriction degree, exercise dose and participant characteristics on NEAT and/or NEPA.
... Conversely, others reported an increase in energy intake in compensators vs. non-compensators. 16,47 Similarly, no changes in energy expenditure across time were noted in some studies, 20,22,35,48,49 whereas others reported lower energy expenditure in compensators vs. non-compensators. 47,50 Given the large degree of variability in these behavioral components across time, discrepancies in these results may be in part explained by the type of measurement tools used (e.g. ...
... 16,47 Similarly, no changes in energy expenditure across time were noted in some studies, 20,22,35,48,49 whereas others reported lower energy expenditure in compensators vs. non-compensators. 47,50 Given the large degree of variability in these behavioral components across time, discrepancies in these results may be in part explained by the type of measurement tools used (e.g. self-reported questionnaires, in-laboratory test meals, accelerometry, doubly labeled water), in addition to the frequency of measurement administration. ...
Article
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Background/objective: Despite the clear health benefits of exercise, exercised-induced weight loss is often less than expected. The term 'exercise energy compensation' is used to define the amount of weight loss below what is expected for the amount of exercise energy expenditure. We examined the dose-response effects of exercise volume on energy compensation in postmenopausal women. Participants/methods: Data from Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were combined for the present analysis. The ALPHA and BETA Trials were two-centred, two-armed, 12-month randomized controlled trials. The ALPHA Trial included 160 participants randomized to 225?min/week of aerobic exercise, and the BETA Trial randomized 200 participants to each 150 and 300?min/week of aerobic exercise. All participants were aged 50-74 years, moderately inactive (<90?min/week of exercise), had no previous cancer diagnosis and a BMI between 22-40?kg/m(2). Energy compensation was based on changes in body composition (DXA scan) and estimated exercise energy expenditure from completed exercise volume. Associations between ?energy intake, ?VO2peak and ?physical activity time with energy compensation were assessed. Results: No differences in energy compensation were noted between interventions. However, there were large inter-individual differences in energy compensation between participants; 9.4% experienced body composition changes that were greater than expected based on exercise energy expenditure, 64% experienced some degree of energy compensation and 26.6% experienced weight gain based on exercise energy expenditure. Increases in VO2peak were associated with reductions in energy compensation (?=-3.44?ml/kg/min, 95% CI for ?=-4.71 to -2.17?ml/kg/min; P=0.0001). Conclusions: Large inter-individual differences in energy compensation were noted, despite no differences between activity doses. Additionally, increases in VO2peak were associated with lower energy compensation. Future studies are needed to identify behavioral and metabolic factors that may contribute to this large inter-individual variability in energy compensation. Trial registration: clinicaltrials.gov identifier: NCT 00522262 (ALPHA Trial); NCT01435005 (BETA Trial).International Journal of Obesity accepted article preview online, 31 March 2017. doi:10.1038/ijo.2017.87.
... Because BMI is calculated from the total weight is preferable to identify the early stages of obesity with help of the body composition evaluation -mainly body fat content [12]. To determine obesity state can be used the 95 percentile of the BMI population data and/ or percent body fat content [13]. ...
... input may be calculated by a multiple of BMR, where size is determined by the constant current lifestyle, specifically implemented motion mode, gender and body dimensions [13]. E output is energy demand of actual movement regimen. ...
... Epidemiological studies over the past 50 years have unanimously shown that low PA and PF are associated with high risk of cardiovascular and total mortality. Recent data also suggest that low PA and PF are followed by an increased incidence of diabetes mellitus and nonfatal cardiovascular diseases, an increase in mental illness, a deterioration in lifestyle [15,31]. For seniors, a higher level of PA and thus increased PF significantly affect the quality and progression of aging -we are speaking about the antiaging effect [4,7,32]. ...
... The daily amount of steps in children must be higher because it is to be expected that children need to learn new movement skills. The recommended daily volume of steps in children is 10000-13000 steps [11,15,22]. In the Czech children we have monitored the amount of daily steps from 8000 to 12000 depending on offer and conditions. ...
Article
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Abstract Introduction. The health benefits of PA are well established and include a lower risk of cardiovascular disease, hypertension, diabetes, and breast and colon cancer. Additionally, PA has positive effects on mental health, delays the onset of dementia, and can help the maintenance of a healthy body mass. Aim of Study. The aim of the study is to summarize the results of the application of appropriate PA based on walking on PF and health in non-trained Czech population differing in age. Material and Methods. The energy output on the level 950 to 2000 kcal (3971-8360 kJ) per week was respected by construction of individual moving programs for seniors, adults and children of both genders. The moving programs consisted of aerobic walking (min 80% of whole exercise) or cycling (min 10% of total exercise) at the level of 50 to 70% VO2max. The duration of exercise session ranged from 20 to 50 min, and training was performed 3-5 times a week during 5 months. The functional variables were assessed on treadmill, body composition with help of bioimpedance analysis. The data were collected in children (142 boys and 124 girls; age 12.6 ± 2.3 years, BM = 36.9 ± 3.0 kg, height = 136.5 ± 2.6 cm, VO2peak = 43.2 ± 3.1 ml·kg–1·min–1) in both men (n = 154) and women (138) of middle age (45.2 ± 7.0, 74.3 ± 3.9, 172.5 ± 2.6, 31.2 ± 3.9), and in seniors of both genders (men n = 71, women n = 112; 71.6 ± 3.6, 77.1 ± 4.1, 171.5 ± 2.9, 26.1 ± 3.1). Results. Interventions with an energy content of 2000 kcal in children, 1500 kcal in adults and 950 kcal in seniors can reduce body mass (about 10%), improve VO2peak (~17%) and motor performance (~15%), reduce the systolic blood pressure (~7 mmHg) regardless of gender, starting values and age. It is also possible to significantly affect the amount of muscle mass (~8%). Conclusions. Reasonable PA is a prerequisite for quality lifestyle and active aging. For seniors, a higher level of PA and thus increased PF significantly affect the quality and progression of aging.
... Because BMI is calculated from the total weight is preferable to identify the early stages of obesity with help of the body composition evaluation -mainly body fat content [12]. To determine obesity state can be used the 95 percentile of the BMI population data and/or percent body fat content [13]. ...
... For the identification of variables that can be used for obesity management can we use the so-called energy balance equation that characterizes energy intake and energy expenditure ΔE = E input -E output E input may be calculated by a multiple of BMR, where size is determined by the constant current lifestyle, specifically implemented motion mode, gender and body dimensions [13]. E output is energy demand of actual movement regimen. ...
Article
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Obesity is blamed for over 2.8 million annual deaths all over the world with increasing prevalence ofrelated comorbidities, including metabolic (e.g. diabetes mellitus, hyperlipidemia, hypertension) andnon-metabolic disorders (e.g. cancer, stroke, depression, polycystic ovary syndrome, fat liver disease,glomerulopathy, bone fragility etc.) The aim of the study was to describe the causes and remedies ofobesity. There are two primary causes for the increase in obesity: lack of an active lifestyle and poornutrition. Fortunately, inactivity and poor nutrition are causes that can be altered throughintervention. The PA based on walking in duration of 5 months were used in subjects withBMI>30kg.m-1. The PA was controlled in 192 middle age women, 67 men of the same age, and 58women seniors with help the pedometer Omron HJ720IT and energy content was controlled by Caltrac,and by relationship between speed of walking and VO2. VO2peak was improved from 13.2±2.1% inwomen to 15.1±2.4% in men, and by 13.0±2.7% in senior women. Similarly was altered the motorperformance – maximal speed of walking on the treadmill about 11.3±2.6% in women and16.2±3.1% inmen, and by 10.8±2.6% in senior women. %BF was decreased by 7.2±1.9% in women and by 6.5±2.0%in men, and by 6.7±2.4% in senior women. Together with these variables were significantly improvedthe predispositions for physical and workload evaluated by ECM/BCM coefficient (6.8±2.5% in women,7.9±3.1% in men, and 8.5±3.0% in senior women). We may concluded that walking with the meanenergy content of 1500kcal.week-1 (9430 ± 840steps.day-1)in females and men of middle age, and energycontent about 1000 kcal.week-1 (6930 ± 610steps.day-1) in senior women is able to significantly reducethe overweight and/or obesity and an improve actual fitness state in subjects without regular movementregime. Therefore, the chance of success in reducing the effects of hypokinesia have only those PA, whichare cheap, safe, well manageable and easily available for sale in the times and conditions, complyingwith the intervened individuals.
... The ineffectiveness of voluntary exercise for weight loss is, at least in part, due to compensatory feedback mechanisms that counterbalance increased energy expenditure (EE) and preserve energy balance. Chronic compensation to exercise (.2 weeks) includes increased food intake (6,7), reduced resting metabolic rate (8)(9)(10), and decreased nonexercise physical activity (11). Acute compensation to exercise (,2 weeks) in mice can be independent of increased food intake (12), suggesting that a decline in nonexercise physical activity may help offset exercise-induced EE in accordance with a "constrained" model of EE (13). ...
Article
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Exercise alone is often ineffective for treating obesity despite the associated increase in metabolic requirements. Decreased nonexercise physical activity has been implicated in this resistance to weight loss, but the mechanisms responsible are unclear. We quantified the metabolic cost of nonexercise activity, or "off-wheel" activity (OWA), and voluntary wheel running (VWR) and examined whether changes in OWA during VWR altered energy balance in chow-fed C57BL/6J mice (n = 12). Energy expenditure (EE), energy intake, and behavior (VWR and OWA) were continuously monitored for 4 days with locked running wheels followed by 9 days with unlocked running wheels. Unlocking the running wheels increased EE as a function of VWR distance. The metabolic cost of exercise (MCE; kcal/m traveled) decreased with increasing VWR speed. Unlocking the wheel led to a negative energy balance, but also decreased OWA, which was predicted to mitigate the expected change in energy balance by ∼45%. A novel behavioral circuit involved repeated bouts of VWR, and roaming was discovered and represented novel predictors of VWR behavior. The integrated analysis described here reveals that the weight loss effects of voluntary exercise can be countered by a reduction in nonexercise activity.
... In other words, this linear relationship assumes that the adult saves the same amount of money for the first unit of BMI lost as the fifth unit of BMI lost. An objection to these linearity assumptions is that relatively modest amounts of weight loss coupled with increases in physical activity can result in significant improvements in health (Herrmann et al., 2015;Kerksick et al., 2009;Weiss et al., 2015). To explore the effects of some nonlinearity in cost effects, we repeated some of our calculations assuming a $237 savings for the first BMI unit, $198 for the second, $158 for the third, $118 for the fourth, and $79 for the fifth. ...
Article
Background: Pediatric obesity presents a significant burden. However, family-based behavioral group (FBBG) obesity interventions are largely uncovered by our health care system. The present study uses Return on Investment (ROI) and Internal Rate of Return (IRR) analyses to analyze the business side of FBBG interventions. METHODS: ROI and IRR were calculated to determine longitudinal cost-effectiveness of a FBBG intervention. Multiple simulations of cost savings are projected using three estimated trajectories of weight change and variations in assumptions. RESULTS: The baseline model of child savings gives an average IRR of 0.2% ± 0.08% and an average ROI of 20.8% ± 0.4%, which represents a break-even IRR and a positive ROI. More pessimistic simulations result in negative IRR values. CONCLUSIONS: Under certain assumptions, FBBGs offer a break-even proposition. Results are limited by lack of data regarding several assumptions, and future research should evaluate changes in cost savings following changes in child and adult weight.
... Impaired response to exercise training may not only result from acquired, but also from inherited factors (7,8). We previously demonstrated that an SNP in the NADH dehydrogenase-1ß subcomplex subunit 6 (NDUFB6) of the mitochondrial complex I relates to impaired muscle mitochondrial plasticity after exercise training in first-degree relatives of type 2 diabetic patients (7,9). ...
... rma.mv function) [19,20] and a simplified dataset of 19 effects (i.e. effect estimates for mid-study [21,22], and sex subgroup comparisons [23,24] were removed). Multivariate meta-analytic models, following random-effects assumptions with maximum-likelihood estimation that accounted for these issues, yielded the same pattern of results: mean effect of 0.3039 (95% CI: -0.0113, 0.6192; p = 0.0588) vs. 0.3001 (95% CI: -0.0344, 0.6347; p = 0.0730) reported in the original publication. ...
... Estimated energy intake in our study, however, was not significantly different between groups (2,376 vs. 2,328 kcal/d, P > 0.05), which is not in accord with other studies suggesting confounding effects of exercise on Figure 4 Simple correlations between change in weight and measures of physical activity (PA) and energy expenditure as measured by a device that combines a three-axis accelerometer and temperature sensors (SenseWear Armband energy intake (25,26). Taken together, our data suggest that the similar weight and FM loss between RYGB and RYGB1EX could have been partially explained by NEPA as suggested in previous studies with (27) and without diet (28,29). ...
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Objective. This study investigated the associations of both physical activity time (PA) and energy expenditure (EE) with weight and fat mass (FM) loss in patients following Roux-en-Y gastric bypass (RYGB) surgery. Methods. Ninety-six nondiabetic patients were included in this analysis. Post-RYGB patients were randomized in one of two treatments: A 6-month exercise training program (RYBG+EX) or lifestyle educational classes (RYGB). Body composition was assessed by dual-energy X-ray absorptiometry and computed tomography. Components of PA and EE were quantified by a multisensory device. Dose-response relationships of both PA and EE with weight loss and body composition were explored according to quartiles of change in steps per day. Results. Patients in the highest quartiles of steps per day change lost more FM (3rd = −19.5 kg and 4th = −22.7 kg, P < 0.05) and abdominal adipose tissue (4th = −313 cm2, P < 0.05), maintained skeletal muscle mass (3rd = −3.1 cm2 and 4th = −4.5 cm2, P < 0.05), and had greater reductions in resting metabolic rate. Decreases in sedentary EE and increases in light EE and age were significant predictors of both Δweight and ΔFM (R2 = 73.8% and R2 = 70.6%, respectively). Conclusions. Nondiabetic patients who perform higher, yet still modest, amounts of PA following RYGB have greater energy deficits and lose more weight and FM, while maintaining higher skeletal muscle mass.
... No significant differences in any parameters assessed were observed between women who did not meet the threshold weight loss compared to those losing ≥ 5% of body weight. The researchers suggest that factors associated with the weight loss response to exercise in women warrant additional investigation [31]. ...
... Adjusting RMR values for age, sex, fat-free mass, and pretrainingVO 2max did not affect the results (Table 14). There was a large pretraining to posttraining increase inVO 2max (17.9%) and small but significant differences in HR sleep , ( The effect of aerobic training has continued to be a topic of interest, with most studies since the 1998 HERITAGE publication showing that aerobic training does not affect RMR (154)(155)(156)(157)(158)(159)(160)(161)(162)(163)(164)(165)(166). One study showed that White women did not experience a change in RMR after 6 months of training, whereas Black women saw a decrease (167). ...
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The aim of the HERITAGE Family Study was to investigate individual differences in response to a standardized endurance exercise program, the role of familial aggregation, and the genetics of response levels of cardiorespiratory fitness and cardiovascular disease and diabetes risk factors. Here we summarize the findings and their potential implications for cardiometabolic health and cardiorespiratory fitness. It begins with overviews of background and planning, recruitment, testing and exercise program protocol, quality control measures, and other relevant organizational issues. A summary of findings is then provided on cardiorespiratory fitness, exercise hemodynamics, insulin and glucose metabolism, lipid and lipoprotein profiles, adiposity and abdominal visceral fat, blood levels of steroids and other hormones, markers of oxidative stress, skeletal muscle morphology and metabolic indicators, and resting metabolic rate. These summaries document the extent of the individual differences in response to a standardized and fully monitored endurance exercise program and document the importance of familial aggregation and heritability level for exercise response traits. Findings from genomic markers, muscle gene expression studies, and proteomic and metabolomics explorations are reviewed, along with lessons learned from a bioinformatics-driven analysis pipeline. The new opportunities being pursued in integrative -omics and physiology have extended considerably the expected life of HERITAGE and are being discussed in relation to the original conceptual model of the study.
... Resting metabolic rate (RMR) was calculated by the ActiHeart software using the equations of Schofield (Schofield 1985), and we averaged these values with those derived from the BodPod, which uses the equations of Nelson (Nelson et al. 1992). The thermic effect of food (TEF) was considered to account for 10% of TEE (Herrmann et al. 2015). Activity energy expenditure (AEE) was then calculated as: ...
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CrossFit<sup>TM</sup> (CF) is a form of high-intensity functional training (HIFT) that focuses on training across the entire spectrum of physical fitness. CF has been shown to improve a number of indicators of health but little information assessing energy balance exists. The purpose of the present study was to investigate energy balance during 1 week of CF training. Men and women (n = 21, mean age and BMI: 43.5 ± 8.4 y; 27.8 ± 4.9 kg·m<sup>-2</sup>), with ≥ 3 months CF experience, had body composition assessed via air displacement plethysmography before and after 1 week of CF training. Participants wore ActiHeart monitors to assess total energy expenditure (TEE), activity energy expenditure (AEE), and CF energy expenditure (CF EE). Energy intake was assessed from TEE and Δ body composition. CF EE averaged 605 ± 219 kcal per 72 ± 10 min session. Weekly CF EE was 2723 ± 986 kcal. Participants were in an energy deficit (TEE: 3674 ± 855 kcal·d<sup>-1</sup>; EI: 3167 ± 1401 kcal·d<sup>-1</sup>). Results of the present study indicate that CF training can account for a significant portion of daily activity energy expenditure. The weekly expenditure is within levels shown to induce clinically meaningful weight loss in overweight/obese populations.
... According to Rowland [8], an increase in physical activity levels would be compensated by decreasing physical activities at another time in order to maintain a stable level of physical activity or energy expenditure over time [9,10]. This compensatory effect has been observed by some [11,12] but not confirmed by other studies [13,14]. ...
Article
Background: The compensatory effect of exercise on total volume of physical activity and food intake has been described as a possible explanation for the limited body weight loss observed during exercise interventions. Objective: To investigate the effect of different exercise intensities on total volume of physical activity and energy intake amongst active men with overweight. Design: Young men with overweight from a naval academy (n = 72; mean ± SD, age 21 ± 2 years, BMI 27.9 ± 2.13 kg/m2) were randomised to a control group (CG), moderate-intensity (MEG), or vigorous-intensity exercise group (VEG). MEG and VEG performed exercise sessions three times per week, for 60 min, during a 2-week period. Physical activity was assessed using triaxial accelerometers for 13 days. Energy intake was assessed at four time-points by 24-hour food recall. Intention-to-treat analyses were performed using linear mixed effect models. Results: MEG and VEG presented a greater compensatory effect in the total volume of physical activity over time compared to CG, with a signifcant difference in the rate of change between VEG and CG (∆ = -250,503 counts vs. ∆ = -61,306 counts, respectively; p = 0.01), and MEG and CG (∆ = -253,336 counts vs. ∆ = -61,306 counts, respectively; p = 0.01). There was no difference between MEG and VEG (p = 0.97). Changes in energy intake were not different between groups (p = 0.18); however, MEG presented greater energy intake compared to CG (β=491 kcal/day; p = 0.01) and VEG (β=319 kcal/day; p = 0.07). VEG presented a greater reduction in body weight compared to MEG (-1.3 kg vs. -0.4 kg; p = 0.03) and CG (-1.3 kg vs. -0.6 kg; p = 0.07). Conclusions: Two weeks of exercise promoted a compensatory effect in total volume of physical activity in active men with overweight, regardless of exercise intensity. The compensatory effect was not observed for energy intake, although there was a trend for higher absolute energy intake in the MEG. Consequently, individuals in the VEG showed greater reduction in body weight over the intervention period.
... Exercise and physical activity (PA) are crit-ically important to prevent and treat overweight and obesity. Current guidelines recommend high levels of PA for weight management [14,15]; however, there is considerable unexplained individual variability in the weight loss response to exercise [16][17][18][19]. ...
Article
Many adults cite exercise as a primary strategy for losing weight, yet exercise alone is modestly effective for weight loss and results in variable weight loss responses. It is possible that some of the variability in weight loss may be explained by the time of day that exercise is performed. Few studies have directly compared the effects of exercise performed at different times of the day (i. e., morning versus evening exercise). Results from these existing studies are mixed with some studies demonstrating superior weight and fat mass loss from morning exercise, while other studies have found that evening exercise may be better for weight management. Exercise timing may alter modifiable lifestyle behaviors involved in weight management, such as non-exercise physical activity, energy intake, and sleep. The purpose of this review is to summarize evidence for and against time-of-day dependent effects of exercise on weight management. Although limited, we also review studies that have examined the effect of exercise timing on other lifestyle behaviors linked to body weight regulation. While exercise at any time of day is beneficial for health, understanding whether there is an optimal time of day to exercise may advance personalized treatment paradigms for weight management.
... There is some evidence of nonresponse to particular kinds of exercise for some people, 240 which could mean experimenting to see what works best at a given time for a given individual at a particular stage of chronic disease. [241][242][243] Compensatory behavior, such as increased eating or reduced activity, may negate any benefits, [244][245][246] so this may also need to be addressed. ...
Article
Precision medicine has captured the imagination of the medical community with visions of therapies precisely targeted to the specific individual’s genetic, biological, social, and environmental profile. However, in practice it has become synonymous with genomic medicine. As such its successes have been limited, with poor predictive or clinical value for the majority of people. It adds little to lifestyle medicine, other than in establishing why a healthy lifestyle is effective in combatting chronic disease. The challenge of lifestyle medicine remains getting people to actually adopt, sustain, and naturalize a healthy lifestyle, and this will require an approach that treats the patient as a person with individual needs and providing them with suitable types of support. The future of lifestyle medicine is holistic and person-centered rather than technological.
... Traditional RCTs opt for a high level of homogeneity within the study population to increase the possibility of presenting a true association between the delivered intervention and outcomes [5]. However, several obesity-focused RCTs have shown high variability regarding the treatment effect, with a great number of non-responders, irrespective of the intervention type (lifestyle or AOMs) [6][7][8][9]. In nutrition, in particular, results of RCTs are often different from the ones obtained in the real-world setting; as a result, several researchers have argued that the design appears to be ill-suited for the delivery of personalized nutrition recommendations [10,11]. ...
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Purpose of Review The n-of-1 clinical trials are considered the epitome of individualized health care. They are employed to address differences in treatment response and adverse events between patients, in a comparative effectiveness manner, extending beyond the delivery of horizontal recommendations for all. Recent Findings The n-of-1 design has been applied to deliver precision exercise interventions, through eHealth and mHealth technologies. Regarding personalized and precision medical nutrition therapy, few trials have implemented dietary manipulations and one series of n-of-1 trials has applied comprehensive genetic data to improve body weight. With regard to anti-obesity medication, pharmacogenetic data could be applied using the n-of-1 trial design, although none have been implemented yet. Summary The n-of-1 clinical trials consist of the only tool for the delivery of evidence-based, personalized obesity treatment (lifestyle and pharmacotherapy), reducing non-responders, while tailoring the best intervention to each patient, through “trial and error”. Their application is expected to improve obesity treatment and mitigate the epidemic.
... In addition, there is substantial interindividual variability in the weight loss response to exercise interventions. Both attenuated weight loss and weight loss variability have been attributed to compensatory mechanisms such as reductions in other components of EE and/or increases in energy intake (EI) [1,[6][7][8][9][10][11][12]. The timing (i.e., time of day) of exercise Nutrients 2022, 14, 816 2 of 13 may affect these compensatory responses and the weight loss response [13][14][15][16][17][18][19][20][21][22][23]. ...
Article
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The purpose of this study was to evaluate the feasibility and acceptability of randomizing adults with overweight and obesity (BMI 25–40 kg/m2) to morning (06:00–10:00) or evening (15:00–19:00) aerobic exercise. Participants completed four exercise sessions per week in the morning (AM, n = 18) or evening (PM, n = 15). The exercise program was 15 weeks and progressed from 70 to 80% heart rate maximum and 750–2000 kcal/week. Bodyweight, body composition, total daily energy expenditure (TDEE), energy intake (EI), sleep, sedentary behavior (SB), non-exercise physical activity (NEPA), and maximal aerobic capacity were assessed at baseline and week 15. Study retention was 94% and adherence to the supervised exercise program was ≥90% in both groups. Weight change was −0.9 ± 2.8 kg and −1.4 ± 2.3 kg in AM and PM, respectively. AM and PM increased TDEE (AM: 222 ± 399 kcal/day, PM: 90 ± 150 kcal/day). EI increased in AM (99 ± 198 kcal/day) and decreased in PM (−21 ± 156 kcal/day) across the intervention. It is feasible to randomize adults with overweight and obesity to morning or evening aerobic exercise with high levels of adherence. Future trials are needed to understand how the timing of exercise affects energy balance and body weight regulation.
... Impaired response to exercise training may not only result from acquired, but also from inherited factors (7,8). We previously demonstrated that an SNP in the NADH dehydrogenase-1ß subcomplex subunit 6 (NDUFB6) of the mitochondrial complex I relates to impaired muscle mitochondrial plasticity after exercise training in first-degree relatives of type 2 diabetic patients (7,9). ...
Article
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The rs540467 SNP in the NDUFB6 gene, encoding a mitochondrial complex I subunit, has been shown to modulate adaptations to exercise training. Interaction effects with diabetes mellitus remain unclear. We assessed associations of habitual physical activity (PA) levels with metabolic variables and examined a possible modifying effect of the rs540467 SNP. Volunteers with type 2 (n=242), type 1 diabetes (n=250) or normal glucose tolerance (control; n=139) were studied at diagnosis and subgroups with type 1 (n=96) and type 2 diabetes (n=95) after 5 years. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamps, oxygen uptake at the ventilator threshold (VO 2 AT) by spiroergometry and PA by questionnaires. Translational studies investigated insulin signaling and mitochondrial function in Ndufb6 siRNA-treated C2C12 myotubes, with electronic pulse stimulation (EPS) to simulate exercising. PA levels were 10 and 6%, VO 2 AT was 31% and 8% lower in type 2 and type 1 diabetes compared to control. Within 5 years, 36% of people with type 2 diabetes did not improve their insulin sensitivity despite increasing PA levels. The NDUFB6 rs540467 SNP modifies PA-mediated changes in insulin sensitivity, body composition and liver fat estimates in type 2 diabetes. Silencing Ndufb6 in myotubes reduced mitochondrial respiration and prevented rescue from palmitate-induced insulin resistance after EPS. A substantial proportion of humans with type 2 diabetes fails to respond to rising PA with increasing insulin sensitivity. This may at least partly relate to a polymorphism of the NDUFB6 gene, which may contribute to modulating mitochondrial function. Clinical Trial Registration ClinicalTrials.gov, identifier NCT01055093. The trial was retrospectively registered on 25 th of January 2010.
... Investigators and research assistants were blinded at the level of outcome assessments and data entry [16,33]. A detailed description of the design and methods for MET-2 [33], results for the primary outcome [6], changes in NExEE and NEPA [16], and differences between intervention responders and non-responders have been published [34]. ...
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Background/objectives: Circadian physiology has been linked to body weight regulation and obesity. To date, few studies have assessed the association between exercise timing and weight related outcomes. The aim of this secondary analysis was to explore the impact of exercise timing (i.e., 24 h clock time of exercise session) on weight loss and components of energy balance. Subjects/methods: Overweight/obese (BMI 25.0-39.9 kg/m2), physically inactive, young adults (~51% female) completed a 10-month supervised exercise program (400 or 600 kcal/session for 5 days/week) or served as non-exercise controls (CON). Participants were categorized based on the time of day in which they completed exercise sessions (Early-Ex: >50% of sessions completed between 7:00 and 11:59 am; (n = 21), Late-Ex: >50% of sessions completed between 3:00 and 7:00 pm; (n = 25), Sporadic-Ex: <50% of sessions completed in any time category; (n = 24), and CON; (n = 18)). Body weight, energy intake (EI; digital photography), and non-exercise physical activity (NEPA; accelerometer) were assessed at baseline, 3.5, 7, and 10 months. Total daily energy expenditure (TDEE; doubly labeled water), was assessed at baseline and 10 months. Results: At month 10, weight loss was significantly greater in both Early-EX (-7.2 ± 1.2%; p < 0.001) and Sporadic-EX (- 5.5 ± 1.2%; p = 0.01) vs CON (+0.5 ± 1.0%), and Early-EX vs Late-EX (-2.1 ± 1.0%; p < 0.001). There were no between group differences for change in TDEE, EI, and non-exercise energy expenditure (P > 0.05). A significant group × time interaction (p = 0.02) was observed for NEPA (counts/min), however, after adjusting for multiple comparisons, group effects were no longer significant. Conclusions: Despite minimal differences in components of energy balance, Early-EX lost significantly more weight compared with Late-Ex. Although the mechanisms are unclear, the timing of exercise may be important for body weight regulation.
... Women from the HIIT group significantly reduced their sitting time corroborating previous findings in healthy individuals in whom total sedentary time was objectively measured. 33 In contrast, others have suggested a compensatory reduction in non-exercise PA in response to aerobic exercise, 13,34 and that people engaging in more MVPA will increase sedentary behaviors during the rest of the day to counteract the energy expenditure increases. 35 There is rationale to justify both potential contradictory responses to an exercise intervention. ...
Article
The hypothesis that people may increase sedentary behavior (SB), referred to as “compensation” in response to exercise interventions, have raised concern. The evidence on “compensation” is contradictory and mostly derived from moderate‐intensity continuous training (MICT) interventions lasting less than 1‐year. The aim was to investigate whether two types of iso‐energetic training (MICT and high‐intensity interval training (HIIT), both combined with resistance training) resulted in compensations on SB, in patients with T2D. Eighty volunteers were randomly assigned to one of three groups (control, MICT, or HIIT), and 54 (59.2±8.2 years) completed a supervised program for 1‐year. Physical activity and SB were measured using Actigraph accelerometers at baseline and in the final month of intervention. Sitting‐time and screen‐time were measured by the long‐version of the International Physical Activity Questionnaire. ANCOVA analysis was used to examine differences between groups at the end of the intervention adjusting for the baseline. No differences in objectively measured and self‐reported SB were observed between groups, but women from the HIIT group reduced their sitting‐time (Δ=170‐min; p=0.048). The absence of change in SB domains between baseline and follow‐up suggests that engaging in MICT and HIIT exercise programs in patients with T2D is unrelated to compensatory increases in SB. This article is protected by copyright. All rights reserved.
... Related to these differences, men often show greater body composition changes in response to exercise, compared to women, who in some cases have been shown to have paradoxical responses to exercise (i.e. gaining body fat) (Herrmann et al. 2015). There is preliminary evidence suggesting that HIIT may overcome hormonal and genetic differences between men and women, supporting more positive responses in women compared to traditional aerobic training (McMullan et al. 2018). ...
Article
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High-intensity interval training (HIIT) promotes positive cardiometabolic and body composition changes. Essential amino acids (EAA) may support changes associated with HIIT, but evaluation of potential synergistic effects is lacking. The purpose of this study was to compare independent and combined effects of HIIT and EAA on total body composition and metabolism in men and women considered overweight/obese; an exploratory aim was to evaluate the modulatory effects of sex. Sixty-six healthy adults (50% female; Age: 36.7 ± 6.0 years; BMI: 32.0 ± 4.2 kg/m2) completed 8 weeks of: (1) HIIT, 2 days/weeks; (2) EAA supplementation, 3.6 g twice daily; (3) HIIT + EAA; or (4) control. Body composition, resting metabolic rate (RMR), substrate metabolism (respiratory exchange ratio; RER), and cardiorespiratory fitness were measured at baseline, 4 weeks, and 8 weeks; cardiometabolic blood markers were measured at baseline and 8 weeks. Differences between groups were assessed by linear mixed models covaried for baseline values, followed by 95% confidence intervals (CI) on adjusted mean change scores. There were no significant changes in body composition (p > 0.05) for any group. Changes in RER, but not RMR, occurred with HIIT (mean change; [95% CI]: − 0.04; [− 0.07, − 0.02]) and EAA (− 0.03; [− 0.06, − 0.01]) after 8 weeks. Cardiorespiratory fitness increased following 8 weeks of HIIT (+ 5.1 ml/kg/min [3.3,6.8]) and HIIT + EAA (+ 4.1 ml/kg/min [1.0,6.4]). Changes with HIIT + EAA were not significantly different from HIIT. There were no changes in cardiometabolic markers (p > 0.05) and no sex interaction (p > 0.05). HIIT is efficacious for promoting positive changes in cardiorespiratory fitness and resting substrate metabolism in adults considered overweight/obese. Addition of EAA did not significantly enhance HIIT-induced adaptations. ClinicalTrials.gov ID#NCT04080102.
... The extent of weight loss in such interventions can be driven by a number of factors, e.g. combined diet and exercise interventions, caloric restriction, non-exercise energy expenditure, and the often ignored compensatory eating (Herrmann et al. 2015;Williams et al. 2015;Caudwell et al. 2014). The lack of dietary intervention in this present study could very well explained the variable weight loss observed among participants. ...
... conceals the marked interindividual variability, with some individuals losing a substantial amount of weight and others losing no weight or even gaining weight during behavioral weight loss interventions (6). Variability of weight loss outcome is an important problem in the treatment of obesity, and understanding the factors underlying this variability may provide clues to more effectively tailor treatments for patients with precision nutrition approaches as described by others (7,8). ...
Article
Objective Identifying predictors of weight loss and clinical outcomes may increase understanding of individual variability in weight loss response. We hypothesized that baseline multiomic features, including DNA methylation (DNAme), metabolomics, and gut microbiome, would be predictive of short‐term changes in body weight and other clinical outcomes within a comprehensive weight loss intervention. Methods Healthy adults with overweight or obesity (n = 62, age 18‐55 years, BMI 27‐45 kg/m², 75.8% female) participated in a 1‐year behavioral weight loss intervention. To identify baseline omic predictors of changes in clinical outcomes at 3 and 6 months, whole‐blood DNAme, plasma metabolites, and gut microbial genera were analyzed. Results A network of multiomic relationships informed predictive models for 10 clinical outcomes (body weight, waist circumference, fat mass, hemoglobin A1c, homeostatic model assessment of insulin resistance, total cholesterol, triglycerides, C‐reactive protein, leptin, and ghrelin) that changed significantly (P < 0.05). For eight of these, adjusted R² ranged from 0.34 to 0.78. Our models identified specific DNAme sites, gut microbes, and metabolites that were predictive of variability in weight loss, waist circumference, and circulating triglycerides and that are biologically relevant to obesity and metabolic pathways. Conclusions These data support the feasibility of using baseline multiomic features to provide insight for precision nutrition–based weight loss interventions.
Chapter
Driven by the increasing burden of chronic diseases and the power of emerging science and technology, medicine is in a phase of transition where monitoring and modifying health status and lifestyle to achieve a high quality of life and prevent chronic diseases will become a centerpiece of health care and society. Medicine will evolve to become more predictive, preventive, personalized, and participatory with proactive interventions emulating these characteristics. © 2017 Michael Sagner. Published by Elsevier Inc. All rights reserved.
Article
Background Although supervised exercise therapy (SET) is effective in improving walking distance among adults with symptomatic peripheral artery disease (PAD), some research suggests that individuals with comorbid PAD and type 2 diabetes mellitus (T2DM) may experience a blunted response to SET. It is unknown whether free-living sedentary time changes during SET, and if increases in sedentary time could, in part, explain poor response to SET. Objectives The purposes of this pilot study were to: 1) determine if older adults with PAD (with and without T2DM) engaging in SET change their sedentary behavior; and 2) examine the relationship between changes in sedentary behavior and SET outcomes. We hypothesized that decreased sedentary time during SET would be associated with greater improvements in six-minute walk test (6MWT) total distance and other key SET outcomes. Methods Participants (n = 44) initiating a 12-week SET program completed the six-minute walk test (6MWT), Short Physical Performance Battery, Walking Impairment Questionnaire, and accelerometer-assessed sedentary behavior at SET initiation, 6 weeks, and 12 weeks. Results Participants’ mean age was 72.3 (7.1) years, mean ankle-brachial index was 0.71 (0.25), and 47.7% were female. On average, sedentary time did not change following SET, although there was substantial variability (-40% to +38% change in minutes of sedentary time/day). Participants with T2DM experienced greater improvements in claudication onset distance when compared to participants without T2DM (mean 35 m, p = .044, 95% CI 1.6 to 115.4 meters). Neither changes in sedentary time from baseline to 6 weeks (p = .419) nor T2DM (p = .154) predicted changes in 6MWT total distance from baseline to 12 weeks. Conclusions As SET availability increases, further examination of factors that may influence SET outcomes will help maximize benefits of this proven therapy.
Article
Although a plethora of evidence supports the benefits of exercise among older adults, a majority of studies have emphasized group differences, while giving little, if any, attention to individual differences. Given the lack of data on variability in response, the present review examined how nonresponse to aerobic exercise has been defined in older adult populations and characteristics associated with nonresponse among older adults. The results of this review suggest that inter-individual variability in response of maximal oxygen consumption to aerobic exercise interventions is prevalent among older adults (1.4-63.4%); age, sex, race, and BMI may not be critical determinants of nonresponse; whereas health status, baseline fitness, and exercise dose appear important. Future intervention studies should evaluate and report the variability in individual response of older adults to exercise; investigators should develop programs that allow for modification of components to assist older adults in achieving optimal benefit from exercise programs.
Chapter
Increasing physical activity through structured aerobic exercise should be a cornerstone of behavioral weight loss programs. Recently, numerous scientific and popular media pieces have discounted the role of exercise for weight loss, which may discourage those trying to lose weight from exercising. However, existing data clearly demonstrate that exercise – either alone or when combined with dietary energy restriction – promotes clinically meaningful weight loss in the majority of people and may be especially important for maintaining weight loss for the long-term. Therefore, the purpose of this chapter is to critically evaluate the role of exercise for weight loss and weight loss maintenance. Topics covered in this chapter include: a discussion of the direct and indirect influences of exercise on energy balance; a review of the impact of exercise on body weight during each stage of obesity treatment; recommendations for incorporating exercise into obesity treatment programs; the role of exercise in the prevention of weight gain; and a discussion of the challenges of making lasting changes in health behaviors.
Article
Economic models predominate in life history research, which investigates the allocation of an organism's resources to growth, reproduction, and maintenance. These approaches typically employ a heuristic Y model of resource allocation, which predicts trade-offs among tasks within a fixed budget. The common currency among tasks is not always specified, but most models imply that metabolic energy, either from food or body stores, is the critical resource. Here, we review the evidence for metabolic energy as the common currency of growth, reproduction, and maintenance, focusing on studies in humans and other vertebrates. We then discuss the flow of energy to competing physiological tasks (physical activity, maintenance, and reproduction or growth) and its effect on life history traits. We propose a Ψ model of energy flow to these tasks, which provides an integrative framework for examining the influence of environmental factors and the expansion and contraction of energy budgets in the evolution of life history strategies.
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The magnitude of the negative energy balance induced by exercise may be reduced due to compensatory increases in energy intake. TO ADDRESS THE QUESTION: Does increased exercise or physical activity alter ad-libitum daily energy intake or macronutrient composition in healthy adults? PubMed and Embase were searched (January 1990-January 2013) for studies that presented data on energy and/or macronutrient intake by level of exercise, physical activity or change in response to exercise. Ninety-nine articles (103 studies) were included. Primary source articles published in English in peer-reviewed journals. Articles that presented data on energy and/or macronutrient intake by level of exercise or physical activity or changes in energy or macronutrient intake in response to acute exercise or exercise training in healthy (non-athlete) adults (mean age 18-64 years). ARTICLES WERE GROUPED BY STUDY DESIGN: cross-sectional, acute/short term, non-randomized, and randomized trials. Considerable heterogeneity existed within study groups for several important study parameters, therefore a meta-analysis was considered inappropriate. Results were synthesized and presented by study design. No effect of physical activity, exercise or exercise training on energy intake was shown in 59% of cross-sectional studies (n = 17), 69% of acute (n = 40), 50% of short-term (n = 10), 92% of non-randomized (n = 12) and 75% of randomized trials (n = 24). Ninety-four percent of acute, 57% of short-term, 100% of non-randomized and 74% of randomized trials found no effect of exercise on macronutrient intake. Forty-six percent of cross-sectional trials found lower fat intake with increased physical activity. The literature is limited by the lack of adequately powered trials of sufficient duration, which have prescribed and measured exercise energy expenditure, or employed adequate assessment methods for energy and macronutrient intake. We found no consistent evidence that increased physical activity or exercise effects energy or macronutrient intake.
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Background/objectives: A decline in resting energy expenditure (REE) beyond that predicted from changes in body composition has been noted following dietary-induced weight loss. However, it is unknown whether a compensatory downregulation in REE also accompanies exercise (EX)-induced weight loss, or whether this adaptive metabolic response influences energy intake (EI). Subjects/methods: Thirty overweight and obese women (body mass index (BMI)=30.6±3.6 kg/m(2)) completed 12 weeks of supervised aerobic EX. Body composition, metabolism, EI and metabolic-related hormones were measured at baseline, week 6 and post intervention. The metabolic adaptation (MA), that is, difference between predicted and measured REE was also calculated post intervention (MApost), with REE predicted using a regression equation generated in an independent sample of 66 overweight and obese women (BMI=31.0±3.9 kg/m(2)). Results: Although mean predicted and measured REE did not differ post intervention, 43% of participants experienced a greater-than-expected decline in REE (-102.9±77.5 kcal per day). MApost was associated with the change in leptin (r=0.47; P=0.04), and the change in resting fat (r=0.52; P=0.01) and carbohydrate oxidation (r=-0.44; P=0.02). Furthermore, MApost was also associated with the change in EI following EX (r=-0.44; P=0.01). Conclusions: Marked variability existed in the adaptive metabolic response to EX. Importantly, those who experienced a downregulation in REE also experienced an upregulation in EI, indicating that the adaptive metabolic response to EX influences both physiological and behavioural components of energy balance.
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Overweight and obesity affects more than 66% of the adult population and is associated with a variety of chronic diseases. Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies. Guidelines of the National Heart, Lung, and Blood Institute (NHLBI) encourage a 10% reduction in weight, although considerable literature indicates reduction in health risk with 3% to 5% reduction in weight. Physical activity (PA) is recommended as a component of weight management for prevention of weight gain, for weight loss, and for prevention of weight regain after weight loss. In 2001, the American College of Sports Medicine (ACSM) published a Position Stand that recommended a minimum of 150 min wk(-1) of moderate-intensity PA for overweight and obese adults to improve health; however, 200-300 min wk(-1) was recommended for long-term weight loss. More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss. To this end, we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain, for weight loss, and prevention of weight regain. Evidence supports moderate-intensity PA between 150 and 250 min wk(-1) to be effective to prevent weight gain. Moderate-intensity PA between 150 and 250 min wk(-1) will provide only modest weight loss. Greater amounts of PA (>250 min wk(-1)) have been associated with clinically significant weight loss. Moderate-intensity PA between 150 and 250 min wk(-1) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction. Cross-sectional and prospective studies indicate that after weight loss, weight maintenance is improved with PA >250 min wk(-1). However, no evidence from well-designed randomized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss. Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk. Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk. There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain.
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In the majority of exercise intervention studies, the aggregate reported weight loss is often small. The efficacy of exercise as a weight loss tool remains in question. The aim of the present study was to investigate the variability in appetite and body weight when participants engaged in a supervised and monitored exercise programme. Fifty-eight obese men and women (BMI = 31.8 +/- 4.5 kg/m2) were prescribed exercise to expend approximately 2092 kJ (500 kcal) per session, five times a week at an intensity of 70 % maximum heart rate for 12 weeks under supervised conditions in the research unit. Body weight and composition, total daily energy intake and various health markers were measured at weeks 0, 4, 8 and 12. Mean reduction in body weight (3.2 +/- 1.98 kg) was significant (P < 0.001); however, there was large individual variability (-14.7 to +2.7 kg). This large variability could be largely attributed to the differences in energy intake over the 12-week intervention. Those participants who failed to lose meaningful weight increased their food intake and reduced intake of fruits and vegetables. These data have demonstrated that even when exercise energy expenditure is high, a healthy diet is still required for weight loss to occur in many people.
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Exercise could contribute to weight loss by altering the sensitivity of the appetite regulatory system. The aim of this study was to assess the effects of 12 wk of mandatory exercise on appetite control. Fifty-eight overweight and obese men and women [mean (+/-SD) body mass index (in kg/m(2)) = 31.8 +/- 4.5, age = 39.6 +/- 9.8 y, and maximal oxygen intake = 29.1 +/- 5.7 mL . kg(-1) . min(-1)] completed 12 wk of supervised exercise in the laboratory. The exercise sessions were designed to expend 2500 kcal/wk. Subjective appetite sensations and the satiating efficiency of a fixed breakfast were compared at baseline (week 0) and at week 12. An Electronic Appetite Rating System was used to measure subjective appetite sensations immediately before and after the fixed breakfast in the immediate postprandial period and across the whole day. The satiety quotient of the breakfast was determined by calculating the change in appetite scores relative to the breakfast's energy content. Despite large variability, there was a significant reduction in mean body weight (3.2 +/- 3.6 kg), fat mass (3.2 +/- 2.2 kg), and waist circumference (5.0 +/- 3.2 cm) after 12 wk. The analysis showed that a reduction in body weight and body composition was accompanied by an increase in fasting hunger and in average hunger across the day (P < 0.0001). Paradoxically, the immediate and delayed satiety quotient of the breakfast also increased significantly (P < 0.05). These data show that the effect of exercise on appetite regulation involves at least 2 processes: an increase in the overall (orexigenic) drive to eat and a concomitant increase in the satiating efficiency of a fixed meal.
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Isotope ratio mass spectrometry of hydrogen and oxygen is frequently used to determine total energy expenditure (TEE) using doubly labeled water. Conventionally, hydrogen isotope ratio is determined in hydrogen gas generated from water samples using zinc reduction. We compare this with a new automated platinum method to determine the ratios of hydrogen isotopes in deuterium-enriched water samples. The platinum method of sample preparation was compared with the zinc method in three ways: analytical variation in deuterium enrichment (within sample; n = 51), analytical variation in TEE estimates (within sample set; n = 10), and level of agreement of TEE estimates between both methods (n = 14). For the zinc method, the standard deviation for multiple sets of triplicate 2H2O sample analysis was +/-4.36 per thousand and +/-2.07 per thousand for platinum. The correlation between TEE estimates when sample sets were analyzed in duplicate was r = 0.89 for zinc and r = 0.83 for platinum. The intercept and slope of the regression line were significantly different from the line of identity for duplicate TEE estimates by zinc but were not different from the line of identity for platinum. After correction for the intra-assay variation of each method, the correlation between zinc and platinum for TEE was 0.77, and the intercept, but not the slope, of the regression was significantly different from the line of identity. The mean difference between the zinc method and the platinum method was 56 kcal/day, and the 95% confidence interval was -438 to 550 kcal/day. These data suggest that the platinum method is at least as reliable as the zinc method as a sample preparation technique for isotope ratio mass spectrometry of deuterium-enriched water samples. The platinum method is also less costly and less labor-intensive than the zinc method.
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The necessity of a 12-h fast before resting metabolic rate (RMR) is measured is often a barrier to measuring RMR. We compared RMR measurements obtained in the morning and afternoon and across repeated days to elucidate the magnitude and sources of variability. Healthy men (n = 12) and women (n = 25) aged 21-67 y, with body mass indexes (in kg/m(2)) ranging from 17 to 34 and body fat ranging from 6% to 54%, completed 4 RMR measurements. RMR measurements were made in the morning (after a 12-h fast and 12 h postexercise) and in the afternoon (after a 4-h fast and 12 h postexercise) on 2 separate days with the ventilated-hood technique. Body composition was assessed by dual-energy X-ray absorptiometry. Mean (+/- SE) afternoon RMR was significantly higher than morning RMR on both visit 1 (1593.5 +/- 35.6 compared with 1508.0 +/- 31.5 kcal/d; P = 0.001) and visit 2 (1602 +/- 29.3 compared with 1511.4 +/- 35.9 kcal/d; P = 0.001). The 2 morning measurements (r = 0.93) and the 2 afternoon measurements (r = 0.93) were highly correlated, and no significant differences between measurements were observed. The mean difference between the morning and afternoon measurements was 99.0 +/- 35.8 kcal/d (6%). Repeated morning and evening measurements of RMR were stable and highly correlated. Day-to-day measurements of RMR were not significantly different. RMR measured in the afternoon after a 4-h fast and exercise was approximately 100 kcal/d higher than RMR measured in the morning.
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The incidence of obesity is increasing rapidly. Research efforts for effective treatment strategies still focus on diet and exercise programmes, the individual components of which have been investigated in intervention trials in order to determine the most effective recommendations for sustained changes in bodyweight. The foremost objective of a weight-loss trial has to be the reduction in body fat leading to a decrease in risk factors for metabolic syndrome. However, a concomitant decline in lean tissue can frequently be observed. Given that fat-free mass (FFM) represents a key determinant of the magnitude of resting metabolic rate (RMR), it follows that a decrease in lean tissue could hinder the progress of weight loss. Therefore, with respect to long-term effectiveness of weight-loss programmes, the loss of fat mass while maintaining FFM and RMR seems desirable. Diet intervention studies suggest spontaneous losses in bodyweight following low-fat diets, and current data on a reduction of the carbohydrate-to-protein ratio of the diet show promising outcomes. Exercise training is associated with an increase in energy expenditure, thus promoting changes in body composition and bodyweight while keeping dietary intake constant. The advantages of strength training may have greater implications than initially proposed with respect to decreasing percentage body fat and sustaining FFM. Research to date suggests that the addition of exercise programmes to dietary restriction can promote more favourable changes in body composition than diet or physical activity on its own. Moreover, recent research indicates that the macronutrient content of the energy-restricted diet may influence body compositional alterations following exercise regimens. Protein emerges as an important factor for the maintenance of or increase in FFM induced by exercise training. Changes in RMR can only partly be accounted for by alterations in respiring tissues, and other yet-undefined mechanisms have to be explored. These outcomes provide the scientific rationale to justify further randomised intervention trials on the synergies between diet and exercise approaches to yield favourable modifications in body composition.
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Caloric restriction (CR) increases maximal life span in short-lived organisms, and its effects are being explored in nonhuman primates. The objectives of this study were to determine the feasibility of prolonged CR in nonobese adults and to compare the effects of CR- and exercise-induced weight loss on body composition and abdominal adiposity. A randomized, controlled trial was conducted with 48 healthy, nonobese women and men, aged 57 +/- 1 (mean +/- standard error [SE]) years, with body mass index 27.3 +/- 0.3 kg/m2. Participants were randomly assigned to a 20% calorically-restricted diet (CR, n = 19), exercise designed to produce a similar energy deficit (EX, n = 19), or a healthy lifestyle control group (HL, n = 10) for 1 year. Assessments included weight, body composition by dual-energy x-ray absorptiometry, abdominal adipose tissue by magnetic resonance imaging, and energy intake by doubly labeled water. The average level of CR achieved by the CR group was 11.5 +/- 2.1%, and the EX group completed 59 +/- 6.7% of their prescribed exercise. Weight changes were greater (p <or=.0005) in the CR (-8.0 +/- 0.9 kg) and EX (-6.4 +/- 0.9) groups as compared to the HL group (-1.3 +/- 0.9 kg), corresponding to reductions of 10.7%, 8.4%, and 1.7% of baseline weights, respectively. Whole-body fat mass and visceral and subcutaneous abdominal adipose tissue decreased significantly (p <.005) and comparably in the CR and EX groups, but did not change in the HL group. CR for 1 year was feasible, but the level of CR achieved was less than prescribed. CR and exercise were equally effective in reducing weight and adiposity.
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The epidemic of obesity is developing faster than the scientific understanding of an efficient way to overcome it, as reflected by the low success rate of short- and long-term weight loss interventions. From a clinical standpoint, this suggests that the body tends to defend a set point of possible genetic origin in the context of a weight-reducing program. As described in this paper, this limited therapeutic success may depend on adaptive thermogenesis, which represents in this case the decrease in energy expenditure (EE) beyond what could be predicted from the changes in fat mass or fat-free mass under conditions of standardized physical activity in response to a decrease in energy intake. This issue has been documented in recent studies that have shown in obese individuals adhering to a weight reduction program a greater than predicted decrease in EE, which in some cases was quantitatively sufficient to overcome the prescribed energy restriction, suggesting a role for adaptive thermogenesis in unsuccessful weight loss interventions and reduced body weight maintenance. As also discussed in this paper, this 'adaptive thermogenesis' can be influenced by environmental factors, which have not been frequently considered up to now. This is potentially the case for plasma organochlorine concentration and oxygen desaturation in obstructive sleep apnea syndrome. It is concluded that health professionals should be aware that in some vulnerable individuals, adaptive thermogenesis can be multi-causal, and has the capacity to compensate, at least partly, for the prescribed energy deficit, possibly going beyond any good compliance of some patients.
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To identify and characterize the individual variability in compensation for exercise-induced changes in energy expenditure (EE). Twelve-week exercise intervention. Thirty-five overweight and obese sedentary men and women (body mass index, 31.8+/-4.1 kg m(-2); age, 39.6+/-11.0 years) were prescribed exercise five times per week for 12 weeks under supervised conditions. Body weight, body composition, resting metabolic rate (RMR), total daily energy intake (EI) and subjective appetite sensations were measured at weeks 0 and 12. When all subjects' data were pooled, the mean reduction in body weight (3.7+/-3.6 kg) was significant (P<0.0001) and as predicted, which suggested no compensation for the increase in EE. However, further examination revealed a large individual variability in weight change (-14.7 to +1.7 kg). Subjects were identified as compensators (C) or noncompensators (NC) based on their actual weight loss (mean NC=6.3+/-3.2 kg and C=1.5+/- 2.5 kg) relative to their predicted weight loss. C and NC were characterized by their different metabolic and behavioural compensatory responses. Moderate changes in RMR occurred in C (-69.2+/-268.7 kcal day(-1)) and NC (14.2+/-242.7 kcal day(-1)). EI and average daily subjective hunger increased by 268.2+/-455.4 kcal day(-1) and 6.9+/-11.4 mm day(-1) in C, whereas EI decreased by 130+/-485 kcal day(-1) and there was no change in subjective appetite (0.4+/-9.6 mm day(-1)) in NC. These results demonstrate that expressing the exercise-induced change in body weight as a group mean conceals the large inter-individual variability in body weight and compensatory responses. Individuals who experience a lower than predicted weight loss are compensating for the increase in EE.
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To determine whether 16 months of moderate-intensity exercise training changes resting metabolic rate (RMR) and substrate oxidation in overweight young adults. Participants were randomly assigned to nonexercise control (CON, 18 women, 15 men) or exercise (EX, 25 women, 16 men) groups. EX performed supervised and verified exercise 3-5 d/wk, 20-45 min/session, at 60-75% of heart-rate reserve. Body mass and composition, maximal oxygen consumption (VO2max), RMR, and resting substrate oxidation were assessed at baseline and after 9 and 16 months of training. EX men had significant decreases from baseline to 9 months in body mass (94.6+/-12.4 to 89.2+/-9.5 kg) and percent fat (28.3+/-4.6 to 24.5+/-3.9). CON women had significant increases in body mass (80.2+/-8.1 to 83.2+/-9.2 kg) from baseline to 16 months. VO2max increased significantly from baseline to 9 months in the EX men (3.67+/-0.62 to 4.34+/-0.58 L/min) and EX women (2.53+/-0.32 to 3.03+/-0.42 L/min). RMR increased from baseline to 9 months in EX women (1,583+/-221 to 1,692+/-230 kcal/d) and EX men (1,995+/-184 to 2,025+/-209 kcal/d). There were no significant differences within genders for either EX or CON in fat or carbohydrate oxidation. Fat oxidation was significantly higher for women than for men at 9 months in both CON and EX groups. Regular moderate-intensity exercise in healthy, previously sedentary overweight and obese adults increases RMR but does not alter resting substrate oxidation. Women tend to have higher RMR and greater fat oxidation, when expressed per kilogram fat-free mass, than men.
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To examine compensatory changes in non-exercise energy expenditure (NEEx) and non-exercise physical activity (NEPA) in response to an aerobic exercise training program. Ninety-two overweight/obese (BMI 25-39.9 kg[BULLET OPERATOR]m) sedentary young adults (18-30 years) completed a 10-month randomized clinical efficacy trial of aerobic exercise 5 d·wk at either 400 kcal·session (n=37), 600 kcal·session (n=37) or control (n=18). Total daily energy expenditure (TDEE) and resting metabolic rate (RMR) were measured at months 0 and 10. NEPA was measured by accelerometer at months 0, 3.5,7, and 10. NEEx was calculated by [(TDEE*0.9)-RMR]-net EEEx (EEEx-RMR). Mixed modeling was used to examine differences between groups (group effect), within groups (time effect) and group-by-time interaction for NEEx and NEPA. Within the exercise groups, there were no significant effects (all p>0.05) of group, time, or group-by-time interaction for NEPA. Additionally, there were no significant within or between group differences for change in NEEx. However, activity cts·min were significantly higher (p<0.001) in the 600 kcal·session group (346 ± 141 min·d) vs. controls (290±106 min·d) at month 7 and significantly higher (p<0.001) in both the 600 kcal·session (345 ± 163 min·d) and 400 kcal·session groups (317 ± 146 min·d) vs. controls (277 ± 116 min·d) at 10 months. A 10-month aerobic exercise training program in previously sedentary, overweight and obese young adults was not associated with compensatory decreases in NEEx or NEPA. Results suggest that overweight and obese individuals do not become less physically active or spend more time in sedentary pursuits in response to exercise.
Article
Prescribed physical activity/exercise training may reduce non-exercise physical activity resulting in no change in total daily energy expenditure and no or minimal exercise-induced weight loss. This systematic review evaluated cross-sectional, short-term (2–14 d), randomized and non-randomized trials which reported on the effect of prescribed physical activity/exercise on non-exercise physical activity/energy expenditure in healthy adults. PubMed and Embase were searched (from January 1990 to March 2013) for articles that presented data on the change in non-exercise physical activity/energy expenditure in response to prescribed physical activity/exercise training. Thirty-one articles were included in this review. One-hundred per cent of cross-sectional studies (n = 4), 90% of short-term studies (n = 10), 50% of non-randomized trials (n = 10) and 100% of randomized trials (n = 7) reported no reductions in non-exercise physical activity/energy expenditure in response to prescribed physical activity/exercise training. We found minimal evidence to support the hypothesis that prescribed physical activity/exercise training results in decreased non-exercise physical activity/energy expenditure in healthy adults. However, this literature is limited by the lack of adequately powered trials designed specifically to evaluate this hypothesis which have included assessments of both the energy expenditure of prescribed exercise and non-exercise energy expenditure using state-of-the-art techniques, i.e. indirect calorimetry and doubly labelled water, respectively.
Article
Exercise is recommended by public health agencies for weight management; however, the role of exercise is generally considered secondary to energy restriction. Few studies exist that have verified completion of exercise, measured the energy expenditure of exercise, and prescribed exercise with equivalent energy expenditure across individuals and genders. OBJECTIVE: The objective of this study was to evaluate aerobic exercise, without energy restriction, on weight loss in sedentary overweight and obese men and women. DESIGN AND METHODS: This investigation was a randomized, controlled, efficacy trial in 141 overweight and obese participants (body mass index, 31.0 ± 4.6 kg/m(2) ; age 22.6 ± 3.9 years). Participants were randomized (2:2:1 ratio) to exercise at either 400 kcal/session or 600 kcal/session or to a nonexercise control. Exercise was supervised, 5 days/week, for 10 months. All participants were instructed to maintain usual ad libitum diets. Because of the efficacy design, completion of ≥90% of exercise sessions was an a priori definition of per protocol, and these participants were included in the analysis. RESULTS: Weight loss from baseline to 10 months for the 400 and 600 kcal/session groups was 3.9 ± 4.9 kg (4.3%) and 5.2 ± 5.6 kg (5.7%), respectively, compared with weight gain for controls of 0.5 ± 3.5 kg (0.5%) (P < 0.05). Differences for weight loss from baseline to 10 months between the exercise groups and differences between men and women within groups were not statistically significant. CONCLUSIONS: Supervised exercise, with equivalent energy expenditure, results in clinically significant weight loss with no significant difference between men and women. This article can be found online at the Wiley Online Library: http://onlinelibrary.wiley.com/doi/10.1002/oby.20145/full
Article
An activity-induced increase in energy expenditure theoretically disturbs energy balance (EB) by creating an acute energy deficit. Compensatory responses could influence the weight loss associated with the energy deficit. Individual variability in compensation for perturbations in EB could partly explain why some individuals fail to lose weight with exercise. It is accepted that the regulatory system will readily defend impositions that promote a negative EB. Therefore, a criticism of exercise interventions is that they will be ineffective and futile methods of weight control because the acute energy deficit is counteracted. Compensation for exercise-induced energy deficits can be categorized into behavioral or metabolic responses and automatic or volitional. An automatic compensatory response is a biological inevitability and considered to be obligatory. An automatic compensatory response is typically a metabolic consequence (e.g., reduced resting metabolic rate) of a negative EB. In contrast, a volitional compensatory response tends to be deliberate and behavioral, which the individual intentionally performs (e.g., increased snack intake). The purpose of this review is to highlight the various metabolic and behavioral compensatory responses that could reduce the effectiveness of exercise and explain why some individuals experience a lower than expected weight loss. We propose that the extent and degree of compensation will vary between individuals. That is, some individuals will be predisposed to compensatory responses that render them resistant to the weight loss benefits theoretically associated with an exercise-induced increase in energy expenditure. Therefore, given the inter-individual variability in behavioral and metabolic compensatory responses, exercise prescriptions might be more effective if tailored to suit individuals.Keywords: energy balance, exercise, appetite
Article
We evaluated weight loss response to 16 months of supervised exercise (45 min/day, 5 days/week, 75% heart-rate-reserve) in sedentary, overweight/obese participants without energy restriction in the Midwest Exercise Trial (MET1). Results indicated men lost weight, women did not. The gender differences were associated with differences in the energy expenditure of exercise (EEEx) (men=667±116; women=439±88 kcal/session) when exercise was prescribed by frequency, intensity and duration. MET2 is a randomized control trial designed and powered to examine differences in weight loss and gender in response to EEEx for men and women of 400 or 600 kcal/session, 5 days/week, for 10 months without energy restriction. One hundred forty-one participants will be randomized to 1 of 2 exercise groups or a non-exercise control. EEEx will be verified by indirect calorimetry monthly during the intervention. This study will evaluate: (1) the weight change response to two levels of EEEx versus non-exercise control; (2) gender differences in weight response to two levels of EEEx; (3) potential compensatory changes in energy intake and/or daily physical activity that may explain the observed weight changes. Results from this study may impact how exercise is prescribed for weight loss and prevention of weight regain and may clarify if men and women differ in response to exercise.
Article
Health benefits of physical activity may depend on a concomitant weight loss. In a randomized, controlled trial, we compared the effects of endurance training with or without weight loss to the effect of weight loss induced by an energy-reduced diet in 48 sedentary, moderately overweight men who completed a 12-week intervention program of training (T), energy-reduced diet (D), training and increased diet (T-iD), or control (C). An energy deficit of 600 kcal/day was induced by endurance training or diet in T and D and a similar training regimen plus an increased dietary intake of 600 kcal/day defined the T-iD group. Primary end point was insulin sensitivity as evaluated by HOMA-IR (mainly reflecting hepatic insulin sensitivity) and hyperinsulinemic, isoglycemic clamps (primarily reflecting peripheral insulin sensitivity). Body mass decreased in T and D by 5.9 ± 0.7 and 5.3 ± 0.7 kg, respectively, whereas T-iD and C remained weight stable. Total and abdominal fat mass were reduced in an additive manner in the T-iD, D, and T groups by 1.9 ± 0.3/0.2 ± 0.1, 4.4 ± 0.7/0.5 ± 0.1, and 7.7 ± 0.8/0.9 ± 0.1 kg, respectively. HOMA-IR was improved in T, D, and T-iD, whereas insulin-stimulated glucose clearance and suppression of plasma nonesterified fatty acids (NEFAs) were increased only in the two training groups. Thus, loss of fat mass (diet or training induced) improves hepatic insulin sensitivity, whereas peripheral insulin sensitivity in skeletal muscle and adipose tissue is increased by endurance training only. This demonstrates that endurance training per se increases various metabolic health parameters and that endurance training should preferably always be included in any intervention regimen for improving metabolic health in moderately overweight men.
Article
The efficacy of physical activity with a healthful diet to reduce obesity is established; however, little is known about the translation of effective lifestyle strategies for obesity reduction in primary care settings. We assessed the effectiveness of a 2-year behaviorally based physical activity and diet program implemented entirely within clinical practices to reduce obesity. A total of 490 sedentary, obese adults were randomized to usual care (n = 241) or to the behavioral intervention (n = 249). The usual care group received advice from their physicians about lifestyle as a strategy for obesity reduction. The behavioral intervention included individual counseling from health educators to promote physical activity with a healthful diet. The primary outcome was change in waist circumference (WC). A total of 396 participants completed the trial (80.8%). A significant main effect was observed for WC change within the intervention compared with usual care (P < .001) that was sustained at 24 months (mean [SE], -0.9 [0.4] vs 0.2 [0.4] cm; P = .05). Secondary analyses revealed significant main effects for change in WC in men (P = .009) and women (P = .02). In men, the mean (SE) reduction in WC at 24 months was greater with behavioral intervention compared with usual care (-1.6 [0.6] vs 0.1 [0.6] cm; P = .049). In women, the behavioral intervention was associated with differences in WC compared with usual care at 6 and 12 months (P ≤ .01) but not at 24 months (P = .10). Behavioral intervention in clinical settings is associated with modest reductions in WC during a 2-year study in obese patients. However, the effectiveness of the intervention is restricted to men. clinicaltrials.gov Identifier: NCT00665158.
Article
PURPOSE:: To examine extent to which changes in non-exercise physical activity contribute to individual differences in body fat loss induced by exercise programs. METHODS:: Thirty four overweight/obese sedentary women (age: 31.7 +/- 8.1 years, BMI: 29.3 +/- 4.3 kg m) exercised for 8 weeks. Body composition, total energy expenditure (TEE), exercise EE (ExEE), activity EE (AEE) calculated as energy expenditure of all active activities minus ExEE, sedentary EE (SEDEE), sleeping EE (SEE), and energy intake were determined before and during the last week of the exercise intervention. RESULTS:: Over the 8-week exercise program net ExEE was 30.2 +/- 12.6 MJ and based on this, body fat loss was predicted to be 0.8 +/- 0.2 kg. For the group as a whole, change in body fat (-0.0 +/- 0.2 kg) was not significant but individual body fat changes ranged from -3.2 kg to +2.6 kg. Eleven participants achieved equal or more than the predicted body fat loss and were classified as 'Responders' and 23 subjects achieved less than the predicted fat loss and were classified as 'Non-responders'. In the group as a whole, daily TEE was increased by 0.62 +/- 0.30 MJ (p<0.05) and the change tended to be different between groups (Responders, +1.44 +/- 0.49 MJ; Non-responders, +0.29 +/- 0.36 MJ, p=0.08). Changes in daily AEE of Responders and Non-responders differed significantly between groups (Responders, +0.79 +/- 0.50 MJ; Non-responders, -0.62 +/- 0.39 MJ, p<0.05). There were no differences between Responders and Non-responders for changes in SEDEE and SEE or energy intake. CONCLUSION:: Overweight and obese women who during exercise intervention achieve lower than predicted fat loss are compensating by being less active outside exercise sessions.
Article
1. Thirty-three arteriovenous forearm catheterization studies were carried out in 19 lean subjects starving for 12–14 h(n = 13), 30–36 h (n = 7) and 60–66 h (n = 13). Forearm blood flow was measured in order to calculate the flux of various substrates. At the same time, whole-body oxidation of fat, carbohydrate and protein was calculated using indirect calorimetry and urinary nitrogen excretion. 2. After an overnight fast (12–14 h), whole-body resting energy expenditure was accounted for by the oxidation of protein (15%), carbohydrate (17%) and fat (68%). At 30–36 h and 60–66 h of starvation, essentially all the non-protein energy was derived from the oxidation of fat (directly plus indirectly via ketone bodies). 3. After an overnight fast, acetoacetate and 3-hydroxybutyrate were taken up by forearm muscle at a rate which could account for 5% of the resting O2 consumption of this tissue. As starvation progressed, forearm muscle took up more acetoacetate and released 3-hydroxybutyrate so that the net uptake of ketone bodies was sufficient to account for about 10% of the resting O2 consumption at 30–36 h of starvation and about 20% at 60–66 h of starvation. 4. The uptake of circulating non-esterified fatty acids by forearm muscle accounted for a greater proportion of the forearm O2 consumption than the uptake of ketone bodies at all times studied. The release of lactate and alanine was significantly greater at 36–40 h and 60–66 h of starvation compared with 12–14 h of starvation, but that of glucose did not change significantly. 5. The results suggest that during early starvation: (a) the release of 3-hydroxybutyrate by muscle (36–66 h starvation) contributes to the circulating 3-hydroxybutyrate concentration, (b) the contribution of ketone bodies to oxidative metabolism in lean subjects is variable but considerably lower than the generally accepted values in obese individuals, and (c) the dominant energy source for the resting muscle of lean individuals between 12 and 66 h of starvation is non-esterified fatty acids.
Article
The variability in resting metabolic rate (RMR), diet-induced thermogenesis (DIT), and fuel utilization rates as well as the impact of several factors on RMR and DIT were assessed in several studies with a total of 103 males and females. The intraindividual CV of RMR and respiratory quotients was 5-6%. The intraindividual variability in DIT and fuel utilization rates was substantially higher. RMR did not change from morning to afternoon. The menstrual cycle phase did not affect RMR and DIT. DIT after mixed meals of 1.3-2.6 MJ could be assessed with good accuracy in 3 h. It is concluded that the low reproducibility of DIT implies that sample sizes of < 10 individuals with one measurement per subject and per treatment have power levels < 80% of assessing true, relatively large (50%) treatment effects or between-group differences in DIT.
Article
To the Editor:— The article by Dr. W. L. Bloom entitled "Fasting as an Introduction to the Treatment of Obesity" (Metabolism8:214 [May] 1959) which was summarized in The Journal, Jan. 23, page 328, prompts me to say that the subject of caloric equivalents of gained or lost weight under varying conditions has hardly been explored by workers in the field of metabolism. Knowledge of the following facts is essential. Carbohydrate and protein cannot be stored dry but retain with them three or more parts of water, while fat can be stored in an almost pure state. One gram of adipose tissue gives the body 8.3 calories of reserve energy, while retention of 1 Gm. of water-soaked glycogen or protein provides only about one calorie. These factors are basic for the determination of the caloric equivalents of gained or lost weight.The average obese patient who is placed on
Article
Exercise generally results in less weight loss than expected and it is frequently observed that men and women do not respond equally to exercise for weight loss. This may be caused by differences in compensation by other components of energy balance or to differences in the energy expenditure of exercise observed between genders.
Article
Seven pairs of young adult male identical twins completed a negative energy balance protocol during which they exercised on cycle ergometers twice a day, 9 out of 10 days, over a period of 93 days while being kept on a constant daily energy and nutrient intake. The total energy deficit caused by exercise above the estimated energy cost of body weight maintenance reached 244 +/- 9.8 MJ (Mean +/- SEM). Baseline energy intake was estimated over a period of 17 days preceding the negative energy balance protocol. Mean body weight loss was 5.0 kg (SEM = 0.6) (p < 0.001) and it was entirely accounted for by the loss of fat mass (p < 0.001). Fat-free mass was unchanged. Body energy losses reached 191 MJ (SEM = 24) (p < 0.001) which represented about 78% of the estimated energy deficit. Subcutaneous fat loss was slightly more pronounced on the trunk than on the limbs as estimated from skinfolds, circumferences, and computed tomograply (CT). The reduction in CT-assessed abdominal visceral fat was quite striking, from 81 cm2 (SEM = 5) to 52 cm2 (SEM = 6) (p < 0.001). At the same submaximal power output level, subjects oxidized more lipids than carbohydrates after the program as indicated by the changes in the respiratory exchange ratio (p < or = 0.05). Intrapair resemblance was observed for the changes in body weight (p < 0.05), fat mass (P < 0.01), percent fat (p < 0.01), body energy content (p < 0.01), sum of 10 skinfolds (p < 0.01), abdominal visceral fat (p < 0.01), fasting plasma triglycerides (p < 0.05) and cholesterol (p < 0.05), maximal oxygen uptake (p < 0.05), and respiratory exchange ratio during submaximal work (p < 0.01). We conclude that even though there were large individual differences in response to the negative energy balance and exercise protocol, subjects with the same genotype were more alike in responses than subjects with different genotypes particularly for body fat, body energy, and abdominal visceral fat changes. High lipid oxidizers and low lipid oxidizers during submaximal exercise were also seen despite the fact that all subjects had experienced the same exercise and nutritional conditions for about three months.
Article
Background: Clinical trials have shown that exercise in adults with overweight or obesity can reduce bodyweight. There has been no quantitative systematic review of this in The Cochrane Library. Objectives: To assess exercise as a means of achieving weight loss in people with overweight or obesity, using randomised controlled clinical trials. Search strategy: Studies were obtained from computerised searches of multiple electronic bibliographic databases. The last search was conducted in January 2006. Selection criteria: Studies were included if they were randomised controlled trials that examined body weight change using one or more physical activity intervention in adults with overweight or obesity at baseline and loss to follow-up of participants of less than 15%. Data collection and analysis: Two authors independently assessed trial quality and extracted data. Main results: The 43 studies included 3476 participants. Although significant heterogeneity in some of the main effects' analyses limited ability to pool effect sizes across some studies, a number of pooled effect sizes were calculated. When compared with no treatment, exercise resulted in small weight losses across studies. Exercise combined with diet resulted in a greater weight reduction than diet alone (WMD -1.1 kg; 95% confidence interval (CI) -1.5 to -0.6). Increasing exercise intensity increased the magnitude of weight loss (WMD -1.5 kg; 95% CI -2.3 to -0.7). There were significant differences in other outcome measures such as serum lipids, blood pressure and fasting plasma glucose. Exercise as a sole weight loss intervention resulted in significant reductions in diastolic blood pressure (WMD -2 mmHg; 95% CI -4 to -1), triglycerides (WMD -0.2 mmol/L; 95% CI -0.3 to -0.1) and fasting glucose (WMD -0.2 mmol/L; 95% CI -0.3 to -0.1). Higher intensity exercise resulted in greater reduction in fasting serum glucose than lower intensity exercise (WMD -0.3 mmol/L; 95% CI -0.5 to -0.2). No data were identified on adverse events, quality of life, morbidity, costs or on mortality. Authors' conclusions: The results of this review support the use of exercise as a weight loss intervention, particularly when combined with dietary change. Exercise is associated with improved cardiovascular disease risk factors even if no weight is lost.
Article
In 1995 the American College of Sports Medicine and the Centers for Disease Control and Prevention published national guidelines on Physical Activity and Public Health. The Committee on Exercise and Cardiac Rehabilitation of the American Heart Association endorsed and supported these recommendations. The purpose of the present report is to update and clarify the 1995 recommendations on the types and amounts of physical activity needed by healthy adults to improve and maintain health. Development of this document was by an expert panel of scientists, including physicians, epidemiologists, exercise scientists, and public health specialists. This panel reviewed advances in pertinent physiologic, epidemiologic, and clinical scientific data, including primary research articles and reviews published since the original recommendation was issued in 1995. Issues considered by the panel included new scientific evidence relating physical activity to health, physical activity recommendations by various organizations in the interim, and communications issues. Key points related to updating the physical activity recommendation were outlined and writing groups were formed. A draft manuscript was prepared and circulated for review to the expert panel as well as to outside experts. Comments were integrated into the final recommendation. PRIMARY RECOMMENDATION: To promote and maintain health, all healthy adults aged 18 to 65 yr need moderate-intensity aerobic (endurance) physical activity for a minimum of 30 min on five days each week or vigorous-intensity aerobic physical activity for a minimum of 20 min on three days each week. [I (A)] Combinations of moderate- and vigorous-intensity activity can be performed to meet this recommendation. [IIa (B)] For example, a person can meet the recommendation by walking briskly for 30 min twice during the week and then jogging for 20 min on two other days. Moderate-intensity aerobic activity, which is generally equivalent to a brisk walk and noticeably accelerates the heart rate, can be accumulated toward the 30-min minimum by performing bouts each lasting 10 or more minutes. [I (B)] Vigorous-intensity activity is exemplified by jogging, and causes rapid breathing and a substantial increase in heart rate. In addition, every adult should perform activities that maintain or increase muscular strength and endurance a minimum of two days each week. [IIa (A)] Because of the dose-response relation between physical activity and health, persons who wish to further improve their personal fitness, reduce their risk for chronic diseases and disabilities or prevent unhealthy weight gain may benefit by exceeding the minimum recommended amounts of physical activity. [I (A)].
Article
To describe physical activity levels of children (6-11 yr), adolescents (12-19 yr), and adults (20+ yr), using objective data obtained with accelerometers from a representative sample of the U.S. population. These results were obtained from the 2003-2004 National Health and Nutritional Examination Survey (NHANES), a cross-sectional study of a complex, multistage probability sample of the civilian, noninstitutionalized U.S. population in the United States. Data are described from 6329 participants who provided at least 1 d of accelerometer data and from 4867 participants who provided four or more days of accelerometer data. Males are more physically active than females. Physical activity declines dramatically across age groups between childhood and adolescence and continues to decline with age. For example, 42% of children ages 6-11 yr obtain the recommended 60 min x d(-1) of physical activity, whereas only 8% of adolescents achieve this goal. Among adults, adherence to the recommendation to obtain 30 min x d(-1) of physical activity is less than 5%. Objective and subjective measures of physical activity give qualitatively similar results regarding gender and age patterns of activity. However, adherence to physical activity recommendations according to accelerometer-measured activity is substantially lower than according to self-report. Great care must be taken when interpreting self-reported physical activity in clinical practice, public health program design and evaluation, and epidemiological research.
Department of Health and Human Services, Physical Activity Advisory Committee