Exercise-induced energy expenditure: implications for exercise prescription and obesity

Beneficial effects of simultaneously targeting calorie intake and calorie efficiency in diet-induced obese mice

Semaglutide is an anti-diabetes and weight loss drug that decreases food intake, slows gastric emptying, and increases insulin secretion. Patients begin treatment with low-dose semaglutide and increase dosage over time as efficacy plateaus. With increasing dosage, there is also greater incidence of gastrointestinal side effects. One reason for the plateau in semaglutide efficacy despite continued low food intake is due to compensatory actions whereby the body becomes more metabolically efficient to defend against further weight loss. Mitochondrial uncoupler drugs decrease metabolic efficiency, therefore we sought to investigate the combination therapy of semaglutide with the mitochondrial uncoupler BAM15 in diet-induced obese mice. Mice were fed high-fat western diet (WD) and stratified into six treatment groups including WD control, BAM15, low-dose semaglutide without or with BAM15, and high-dose semaglutide without or with BAM15. Combining BAM15 with either semaglutide dose decreased body fat and liver triglycerides, which was not achieved by any monotherapy, while high-dose semaglutide with BAM15 had the greatest effect on glucose homeostasis. This study demonstrates a novel approach to improve weight loss without loss of lean mass and improve glucose control by simultaneously targeting energy intake and energy efficiency. Such a combination may decrease the need for semaglutide dose escalation and hence minimize potential gastrointestinal side effects.

Compensatory effects of different exercise durations on non-exercise physical activity, appetite, and energy intake in normal weight and overweight adults

Objectives: To examine compensatory changes of different exercise durations on non-exercise physical activity (NEPA), appetite, and energy intake (EI) in normal and overweight adults, and to determine if different body mass index of individuals interact with these compensatory effects.

Methods: Ten normal weight adults (nine females and one male; age: 24.0 ± 0.4 years; BMI: 20.7 ± 0.5 kg/m²) and ten overweight adults (six females and four males; age: 24.5 ± 0.9 years; BMI: 25.9 ± 0.4 kg/m²) participated in this study. The participants completed two exercise trials: short-duration continuous training (SDCT) and long-duration continuous training (LDCT), i.e., a 40 min short-duration and an 80 min long-duration continuous training in a randomized order. Total physical activity and NEPA were monitored using an accelerometer for seven consecutive days, which involved a two-day baseline observation period (C-pre-Ex), three-day exercise intervention period (Ex), and two-day follow-up period (C-post-Ex). Blood samples were collected for appetite-related hormone analysis. Appetite score was assessed using the visual analogue scale. Energy intake was evaluated by weighing the food and recording diaries.

Results: The NEPA evaluation showed that it was higher for SDCT than for LDCT in the C-post-Ex period (F (1, 19) = 8.508, p = 0.009) in the total sample. Moreover, results also indicated that NEPA was lower for LDCT (F (2, 18) = 6.316, p = 0.020) and higher for SDCT (F (2, 18) = 3.889, p = 0.026) in the C-post-Ex period than in the C-pre-Ex and Ex periods in overweight group. Acyl-ghrelin revealed a main effect of time in the total sample and in normal weight and overweight groups; it was lower in the C-post-Ex period than in the C-pre-Ex and Ex periods (all p < 0.05). Total EI analysis revealed no significant changes in either the total sample or in the normal weight and overweight groups.

Conclusion: These findings demonstrate that short duration exercise led to a compensatory increment in NEPA, whereas long duration exercise induced a compensatory decrease in NEPA. Moreover, there was a higher and delayed compensatory response in overweight adults than in normal weight adults. Nevertheless, energy intake was not changed across time, regardless of exercise duration.

The Mystery of Energy Compensation

AbstractThe 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.

Effect of Combined Interval and Continuous Exercise Training on Gastric Emptying, Appetite, and Adaptive Responses in Men With Overweight and Obesity

Background/Objectives: Characterizing compensatory and adaptive responses to exercise assists in understanding changes in energy balance and health outcomes with exercise interventions. This study investigated the effects of a short-term exercise intervention (combining high intensity interval (HII) and continuous exercise) on (1) gastric emptying, appetite and energy intake; and (2) other adaptive responses including cardiorespiratory fitness, in inactive men with overweight/obesity. Methods: Fifteen men (BMI: 29.7 ± 3.3 kg/m^-2) completed a 4-wk supervised exercise intervention, consisting of 5 exercise sessions per week alternating between HII (30 s at 100% VO₂max followed by 30 s recovery) and continuous (at 50% VO₂max) training on a cycle ergometer, progressing from 30 to 45 min session duration. Gastric emptying (¹³C-octanoic acid breath test), appetite (visual analog scale), energy intake (ad libitum lunch meal), body composition (air displacement plethysmography), non-exercise activity (accelerometery) VO₂max, blood pressure, and fasting concentrations of glucose, insulin, and ghrelin were measured before and after (≥48 h) the intervention. Results: Gastric emptying, glucose, insulin and ghrelin were unchanged, but energy intake at the ad libitum lunch test meal significantly increased at post-intervention (+171 ± 116 kcal, p < 0.01). Body weight (-0.9 ± 1.1 kg), waist circumference (-2.3 ± 3.5 cm) and percent body fat (-0.9 ± 1.1%) were modestly reduced (P < 0.05). VO₂max increased (+4.4 ± 2.1 ml.kg.min^-1) by 13% and systolic (-6.2 ± 8.4 mmHg) and diastolic (-5.8 ± 2.2 mmHg) blood pressure were significantly reduced (P ≤ 0.01 for all). Conclusions: Four weeks of exercise training did not alter gastric emptying, indicating gastric emptying may only adapt to a higher volume/longer duration of exercise or changes in other characteristics associated with regular exercise. The combination of HII and continuous exercise training had beneficial effects on body composition, cardiorespiratory fitness, and blood pressure and warrants further investigation in larger randomized controlled trials.

What is the exercise intensity of Pilates? An analysis of the energy expenditure, blood lactate, and intensity of apparatus and mat Pilates sessions

BACKGROUND

Pilates is a form of exercise commonly used in rehabilitation settings that improves muscular fitness and flexibility. However, it is unknown whether the energy expenditure (EE) from Pilates sessions could also lead to the intensity suggested by health organizations to improve physical fitness. This study aimed to quantify and compare the intensity and the EE of two different Pilates sessions (mat and apparatus).

METHODS

18 healthy females (age: 22 ± 3 years; height: 1.6 ± 0.1m; body mass: 61.0 ± 10.0 kg; body mass index: 21 ± 3 kg/m²) performed two different sessions. Each session involved the performance of 15 exercises. Oxygen consumption (V˙O₂) was measured continuously and then converted to EE in Kcal/min. Blood lactate, heart rate (HR), and blood pressure (BP) were also measured. A repeated measures two-way ANOVA (time X group) determined differences between sessions. Bonferroni's post hoc analysis was used to identify significant differences between measures.

RESULTS

The Reformer apparatus and Mat sessions presented an EE of 2.59 ± 0.53 and 1.93 ± 0.26 kcal/min, respectively. V˙O₂ was higher for the Reformer session (8.67 ± 1.15 ml/kg/min) when compared to Mat (6.44 ± 0.73 ml/kg/min). There was no significant increase in blood lactate, HR, and BP for either session above resting values.

CONCLUSION

The Pilates sessions analyzed in this study elicit low cardiovascular stress, leading to low EE levels. However, a typical session performed on the Reformer apparatus presented a higher EE, V˙O_2, and HR compared to the Mat Pilates session.

Does sedentary time increase in older adults in the days following participation in intense exercise?

BACKGROUND

Older adults have the highest sedentary time across all age groups, and only a small portion is meeting the minimum recommendations for weekly physical activity. Little research to date has looked at how changes in one of these behaviours influences the other.

AIM

To assess changes in 24-h movement behaviours (sedentary time, light intensity physical activity (LPA), moderate-vigorous PA (MVPA) and sleep) over three consecutive days, following acute bouts of exercise of varying intensity in older adults.

METHODS

Participants (n = 28, 69.7 ± 6.5 years) completed a maximal exercise test and the following exercise protocols in random order: moderate continuous exercise (MOD), high-intensity interval exercise (HI) and sprint interval exercise (SPRT). A thigh-worn device (ActivPAL™) was used to measure movement behaviours at baseline and the 3 days following each exercise session.

RESULTS

Repeated measures analysis of variance indicated that compared to baseline, participants decreased MVPA in the 3 days following all exercise sessions and decreased LPA following HI and SPRT (p < 0.05). Over half of the sample had clinically meaningful increases in sedentary time (30 min/day) in the days following exercise participation.

DISCUSSION

Older adults who compensate for exercise participation by reducing physical activity and increasing sedentary time in subsequent days may require behavioural counseling to ensure that incidental and recreational physical activities are not reduced.

CONCLUSION

It appears that older adults compensate for acute exercise by decreasing MVPA and LPA, and increasing sedentary time in the days following exercise. Future research is needed to determine whether compensation persists with regular engagement.

Dietary Energy Partition: The Central Role of Glucose

Humans have developed effective survival mechanisms under conditions of nutrient (and energy) scarcity. Nevertheless, today, most humans face a quite different situation: excess of nutrients, especially those high in amino-nitrogen and energy (largely fat). The lack of mechanisms to prevent energy overload and the effective persistence of the mechanisms hoarding key nutrients such as amino acids has resulted in deep disorders of substrate handling. There is too often a massive untreatable accumulation of body fat in the presence of severe metabolic disorders of energy utilization and disposal, which become chronic and go much beyond the most obvious problems: diabetes, circulatory, renal and nervous disorders included loosely within the metabolic syndrome. We lack basic knowledge on diet nutrient dynamics at the tissue-cell metabolism level, and this adds to widely used medical procedures lacking sufficient scientific support, with limited or nil success. In the present longitudinal analysis of the fate of dietary nutrients, we have focused on glucose as an example of a largely unknown entity. Even most studies on hyper-energetic diets or their later consequences tend to ignore the critical role of carbohydrate (and nitrogen disposal) as (probably) the two main factors affecting the substrate partition and metabolism.

The Effect of Exercise Training on Total Daily Energy Expenditure and Body Composition in Weight-Stable Adults: A Randomized, Controlled Trial

BACKGROUND

The present study examined, among weight-stable overweight or obese adults, the effect of increasing doses of exercise energy expenditure (EEex) on changes in total daily energy expenditure (TDEE), total body energy stores, and body composition.

METHODS

Healthy, sedentary overweight/obese young adults were randomized to one of 3 groups for a period of 26 weeks: moderate-exercise (EEex goal of 17.5 kcal/kg/wk), high-exercise (EEex goal of 35 kcal/kg/wk), or observation group. Individuals maintained body weight within 3% of baseline. Pre/postphysical activity between-group measurements included body composition, calculated energy intake, TDEE, energy stores, and resting metabolic rate.

RESULTS

Sixty weight-stable individuals completed the protocols. Exercise groups increased EEex in a stepwise manner compared with the observation group (P < .001). There was no group effect on changes in TDEE, energy intake, fat-free mass, or resting metabolic rate. Fat mass and energy stores decreased among the females in the high-exercise group (P = .007).

CONCLUSIONS

The increase in EEex did not result in an equivalent increase in TDEE. There was a sex difference in the relationship among energy balance components. These results suggest a weight-independent compensatory response to exercise training with potentially a sex-specific adjustment in body composition.

Energy Compensation Following a Supervised Exercise Intervention in Women Living With Overweight/Obesity Is Accompanied by an Early and Sustained Decrease in Non-structured Physical Activity

Background/Objectives

Body composition (BC) does not always vary as a function of exercise induced energy expenditure (exercise EE – resting EE). Energy balance variables were measured to understand energy compensation (EC) in response to an exercise intervention performed at low (LOW) or moderate (MOD) intensity.

Subjects/Methods

Twenty-one women with overweight/obesity (33 ± 5 kg/m²; 29 ± 10 yrs; 31 ± 4 ml O₂/kg/min) were randomized to a 3-month LOW or MOD (40 or 60% of VȮ_2reserve, respectively) matched to expend 1500 kcal/week (compliance = 97 ± 5%). Body energy stores (DXA), energy intake (EI) (food menu and food diaries), resting EE (indirect calorimetry), total EE (doubly-labeled water), time spent in different activities (accelerometers), appetite (visual analog scale), eating behavior traits and food reward (liking and wanting) were assessed at baseline, after weeks 1 and 2 and at the end of the 3-month exercise intervention.

Results

EC based on BC changes (fat mass and fat-free mass) was 49 ± 79% and 161 ± 88% in LOW and MOD groups, respectively (p = 0.010). EI did not change significantly during the intervention. However, eating behavior traits and food reward had changed by the end of the 3-month supervised exercise. Non-structured physical activity (NSPA) decreased across the intervention (p < 0.002), independent of the intensity of the exercise training.

Conclusion

Women with overweight/obesity training at LOW presented lower EC for a given energy cost of exercise. Our results strongly suggest that NSPA plays a major role in mediating the effects of exercise on energy balance and ultimately on changes in BC.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier ISRCTN31641049.

Unprompted vigorous physical activity is associated with higher levels of subsequent sedentary behaviour in participants with low cardiorespiratory fitness: a cross-sectional study

Performing physical activity is considered health promoting but may induce a need for subsequent rest periods. This study aimed to determine the within-day interactions between vigorous physical activity (VPA) and sedentary behaviour (SB) in participants with low cardiorespiratory fitness. We tested the hypothesis that VPA is associated with a temporary subsequent increase in SB. One week of accelerometer data containing a minimum of one 10-min bout of VPA from 62 participants with low cardiorespiratory fitness (31-50 years old) were obtained from the MILE study. A comparison of SB was made between days with a bout of VPA and days without (control). Due to a positive association between VPA and number and duration of sedentary bouts, the time accumulated in both uninterrupted and total sedentary bouts were 27 (95% CI, 10-45) min and 29 (95% CI, 9-50) min higher on VPA days compared to control days (P < 0.05). Our results indicate that in participants with low cardiovascular fitness, unprompted VPA is positively associated with an increase in subsequent sedentary time. We propose that such VPA-associated sedentary time may be viewed as part of a healthy activity pattern.

How much exercise should be promoted to raise total daily energy expenditure and improve health?

Despite longstanding recognition of the benefits of a physically active lifestyle, there remains ambiguity regarding exactly how much exercise should be promoted to raise total energy expenditure (TEE) and improve health. This review provides a brief summary of the dose-response relationship between physical activity and relative risk of morbidity and mortality; mechanisms through which exercise drives an increase in TEE; the highest reported levels of TEE measured via doubly labelled water; and the potential impact of non-compliance and confounders in moderating the contribution of exercise to increase TEE. Cohort studies provide a compelling argument that 'more is better' regarding the exercise dose for increasing TEE, that increasing TEE is protective for health, and that this is mediated through increased cardiorespiratory fitness. However, growing evidence shows that ever increasing volumes of weekly physical activity may reverse the cost-benefit seen with more modest doses. Animal and human studies show that the elevation in TEE associated with increasing exercise volume is commonly less than expected, due to physiological confounders. Further, there is considerable evidence of behavioural non-compliance to planned exercise in all but the most highly motivated athletes. Therefore, inbuilt defence mechanisms may safeguard against TEE being elevated to maximum levels.

A "NEAT" Approach to Obesity Prevention in the Modern Work Environment

Increased prevalence of obesity may be due to an increase of being sedentary at work. Increasing non-exercise activity thermogenesis (NEAT) using walking workstations may increase total physical activity and promote a leaner physical body composition (or phenotype). The purpose of this study was to test whether walking slowly during work was sufficient to promote a leaner phenotype by increasing physical activity in sedentary desk workers without inducing compensation or a decrease in activity or energy expenditure during the nonworking hours. We conducted a prospective cohort study using a within-subjects crossover design. The design involved two phases each lasting 2 weeks: a treadmill exercise phase in which subjects used a walking workstation for 2.5 hours a day 5 days/week and a control phase in which subjects maintained their normal work activity. Twenty-five sedentary adults working at the Minneapolis VA Health Care System. We measured body weight, body composition, food intake, 24-hour physical activity, and self-reported physical activity with the International Physical Activity Questionnaire (IPAQ). Treadmill exercise caused a leaner phenotype (lean mass gain and fat mass loss) and significantly increased their 24-hour physical activity. Walking workstation use had favorable effects on physical well-being and mental focus and did not adversely affect productivity. Light treadmill exercise during work can increase physical activity and result in a leaner body composition. This is a potentially useful intervention to increase NEAT in the modern sedentary work environment.

What is the effect of diet and/or exercise interventions on behavioural compensation in non-exercise physical activity and related energy expenditure of free-living adults? A systematic review

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.

Energy expenditure responses to exercise training in older women

Previous studies have shown inconsistent findings regarding how structured exercise affects energy expenditure (EE). This study was designed to determine the changes in EE and physical activity following exercise training in older women. Nonobese (body mass index = 25.8 ± 3.4 kg·m⁻²) women (60–75 years, n = 72) completed a 4‐month supervised aerobic exercise training of lower‐ or higher‐dose (33.6 and 58.8 kJ·kg⁻¹ body weight weekly, respectively) at 50–55% of heart rate reserve. Total daily EE (TDEE) by the doubly labeled water method, resting metabolic rate (RMR) via indirect calorimetry, and physical activity by accelerometer were determined before and at the end of exercise training. Nonexercise activity thermogenesis (NEAT) was calculated. Following exercise training, the changes in components of TDEE and total physical activity did not differ by group. In the entire sample, TDEE, RMR, NEAT and total physical activity did not change (P > 0.05 for all). However, a significant baseline physical activity × time interaction was found for several of the variables. Data were therefore stratified into tertiles of baseline physical activity. In the high tertile, TDEE remained unchanged, but total physical activity decreased (P = 0.012). In contrast, in the middle and low tertiles, NEAT remained unchanged, and total physical activity increased (P < 0.05 for both). In conclusion, aerobic exercise training did not change TDEE, RMR, NEAT, or total physical activity in this sample of older women. Exercise dose did not, but baseline physical activity levels might, influence EE responses and total physical activity changes.

Exercise training improves fat metabolism independent of total energy expenditure in sedentary overweight men, but does not restore lean metabolic phenotype

BACKGROUND

Obesity is a dietary fat storage disease. Although exercise prevents weight gain, effects of chronic training on dietary fat oxidation remains understudied in overweight adults.

OBJECTIVE

We tested whether 2 months of training at current guidelines increase dietary fat oxidation in sedentary overweight adults like in sedentary lean adults.

DESIGN

Sedentary lean (n=10) and overweight (n=9) men trained on a cycle ergometer at 50% VO_2peak, 1 h day^-1, four times per week, for 2 months while energy balance was clamped. Metabolic fate of [d₃₁]palmitate and [1-¹³C]oleate mixed in standard meals, total substrate use, total energy expenditure (TEE), activity energy expenditure (AEE) and key muscle proteins/enzymes were measured before and at the end of the intervention.

RESULTS

Conversely to lean subjects, TEE and AEE did not increase in overweight participants due to a spontaneous decrease in non-training AEE. Despite this compensatory behavior, aerobic fitness, insulin sensitivity and fat oxidation were improved by exercise training. The latter was not explained by changes in dietary fat trafficking but more likely by a coordinated response at the muscle level enhancing fat uptake, acylation and oxidation (FABPpm, CD36, FATP1, ACSL1, CPT1, mtGPAT). ACSL1 fold change positively correlated with total fasting (R²=0.59, P<0.0001) and post-prandial (R²=0.49, P=0.0006) fat oxidation whereas mtGPAT fold change negatively correlated with dietary palmitate oxidation (R²=0.40, P=0.009), suggesting modified fat trafficking between oxidation and storage within the muscle. However, for most of the measured parameters the post-training values observed in overweight adults remained lower than the pre-training values observed in the lean subjects.

CONCLUSION

Independent of energy balance and TEE, exercise training at current recommendations improved fitness and fat oxidation in overweight adults. However the improved metabolic phenotype of overweight adults was not as healthy as the one of their lean counterparts before the 2-month training, likely due to the spontaneous reduction in non-training AEE.

Obesity and energy balance: What is the role of physical activity?

Despite billions of dollars spent over decades of research, debate remains over the causes and solutions of the obesity epidemic. The specific role of physical activity in the prevention or treatment of obesity seems a particularly contentious issue, with opposing views put forth in both academic and popular media. In an attempt to provide context and clarity to the specific question of the role of physical activity in determination of body weight, we have attempted to identify evidence or lack thereof in the scientific literature and provide a summary of our findings. Areas covered: Topics included in this narrative review are an overview of energy balance, the relationship between physical activity and energy expenditure, compensatory responses in non-exercise energy expenditure and energy intake, and the relationship between physical activity and obesity. Expert commentary: Based on a review of the existing literature, daily physical activity and structured exercise has beneficial effects on an individual's body weight. In most instances, exercise occurring in adequate amounts will increase total daily energy expenditure and create an acute energy deficit, without compensatory decreases in non-exercise physical activity or energy expenditure nor compensatory increases in energy intake. Several gaps in the literature exist, both in terms of the number of adequately powered clinical trials with rigorous assessments of both energy intake and expenditure, and with a variety of study populations (by age, sex, race, etc.) and with varying exercise volumes and intensities.

Do Running and Strength Exercises Reduce Daily Muscle Inactivity Time?

Understanding how a specific exercise changes daily activity patterns is important when designing physical activity interventions. We examined the effects of strength and interval running exercise sessions on daily activity patterns using recordings of quadriceps and hamstring muscle electromyographic (EMG) activity and inactivity. Five male and five female subjects taking part in a 10-week training programme containing both strength and interval running training sessions were measured for daily muscle EMG activities during three days: on a strength day, an interval running day, and a day without exercise. EMG was measured using textile electrodes embedded into sport shorts that were worn 9.1 ± 1.4 hours/day and results are given as % of recording time. During the total measurement time the muscles were inactive 55 ± 26%, 53 ± 30% and 71 ± 12% during strength training day, interval running day, and day without exercise (n.s.). When compared to the day without exercise, the change in muscle inactivity correlated negatively with change in light muscle activity in strength (r = -0.971, p < 0.001) and interval running days (r = -0.965, p < 0.001). While interval running exercise bout induced a more systematic decrease in muscle inactivity time (from 62 ± 15% to 6 ± 6%, p < 0.001), reductions in muscle inactivity in response to strength exercise were highly individual (range 5–70 pp) despite the same training programme. Strength, but not running exercise bout, increased muscle activity levels occurring above 50% MVC (p < 0.05) when compared to a similar period without exercise. The effect of strength exercise bout on total daily recording time increased the EMG amplitudes across the entire intensity spectrum. While strength and interval running exercise are effective in increasing muscle moderate-to-vigorous activity when compared to a similar period without exercise, it comprises only a small part of the day and does not seem to have a systematic effect neither to reduce nor induce compensatory increase in the daily muscle inactivity that is highly heterogeneous between individuals.

Effects of a 12-week aerobic exercise intervention on eating behaviour, food cravings, and 7-day energy intake and energy expenditure in inactive men

This study examined effects of 12 weeks of moderate-intensity aerobic exercise on eating behaviour, food cravings, and weekly energy intake and expenditure in inactive men. Eleven healthy men (mean ± SD: age, 26 ± 5 years; body mass index, 24.6 ± 3.8 kg·m^-2; maximum oxygen uptake, 43.1 ± 7.4 mL·kg^-1·min^-1) completed the 12-week supervised exercise programme. Body composition, health markers (e.g., blood pressure), eating behaviour, food cravings, and weekly energy intake and expenditure were assessed before and after the exercise intervention. There were no intervention effects on weekly free-living energy intake (p = 0.326, d = -0.12) and expenditure (p = 0.799, d = 0.04) or uncontrolled eating and emotional eating scores (p > 0.05). However, there was a trend with a medium effect size (p = 0.058, d = 0.68) for cognitive restraint to be greater after the exercise intervention. Total food cravings (p = 0.009, d = -1.19) and specific cravings of high-fat foods (p = 0.023, d = -0.90), fast-food fats (p = 0.009, d = -0.71), and carbohydrates/starches (p = 0.009, d = -0.56) decreased from baseline to 12 weeks. Moreover, there was a trend with a large effect size for cravings of sweets (p = 0.052, d = -0.86) to be lower after the exercise intervention. In summary, 12 weeks of moderate-intensity aerobic exercise reduced food cravings and increased cognitive restraint, but these changes were not accompanied by changes in other eating behaviours or weekly energy intake and expenditure. The results indicate the importance of exercising for health improvements even when reductions in body mass are modest.

Predictors of fat mass changes in response to aerobic exercise training in women

Aerobic exercise training in women typically results in minimal fat loss, with considerable individual variability. We hypothesized that women with higher baseline body fat would lose more body fat in response to exercise training and that early fat loss would predict final fat loss. Eighty-one sedentary premenopausal women (age: 30.7 ± 7.8 years; height: 164.5 ± 7.4 cm; weight: 68.2 ± 16.4 kg; fat percent: 38.1 ± 8.8) underwent dual-energy x-ray absorptiometry before and after 12 weeks of supervised treadmill walking 3 days per week for 30 minutes at 70% of (Equation is included in full-text article.). Overall, women did not lose body weight or fat mass. However, considerable individual variability was observed for changes in body weight (-11.7 to +4.8 kg) and fat mass (-11.8 to +3.7 kg). Fifty-five women were classified as compensators and, as a group, gained fat mass (25.6 ± 11.1 kg to 26.1 ± 11.3 kg; p < 0.001). The strongest correlates of change in body fat at 12 weeks were change in body weight (r = 0.52) and fat mass (r = 0.48) at 4 weeks. Stepwise regression analysis that included change in body weight and body fat at 4 weeks and submaximal exercise energy expenditure yielded a prediction model that explained 37% of the variance in fat mass change (R = 0.37, p < 0.001). Change in body weight and fat mass at 4 weeks were moderate predictors of fat loss and may potentially be useful for identification of individuals who achieve less than expected weight loss or experience unintended fat gain in response to exercise training.

Change in energy expenditure and physical activity in response to aerobic and resistance exercise programs

Exercise is considered an important component of a healthy lifestyle but there remains controversy on effects of exercise on non-exercise physical activity (PA). The present study examined the prospective association of aerobic and resistance exercise with total daily energy expenditure and PA in previously sedentary, young men. Nine men (27.0 ± 3.3 years) completed two 16-week exercise programs (3 exercise sessions per week) of aerobic and resistance exercise separated by a minimum of 6 weeks in random order. Energy expenditure and PA were measured with the SenseWear Mini Armband prior to each intervention as well as during week 1, week 8 and week 16 of the aerobic and resistance exercise program. Body composition was measured via dual x-ray absorptiometry. Body composition did not change in response to either exercise intervention. Total daily energy expenditure on exercise days increased by 443 ± 126 kcal/d and 239 ± 152 kcal/d for aerobic and resistance exercise, respectively (p < 0.01). Non-exercise moderate-to-vigorous PA, however, decreased on aerobic exercise days (−148 ± 161 kcal/d; p = 0.03). There was no change in total daily energy expenditure and PA on non-exercise days with aerobic exercise while resistance exercise was associated with an increase in moderate-to-vigorous PA during non-exercise days (216 ± 178 kcal/d, p = 0.01). Results of the present study suggest a compensatory reduction in PA in response to aerobic exercise. Resistance exercise, on the other hand, appears to facilitate non-exercise PA, particularly on non-exercise days, which may lead to more sustainable adaptations in response to an exercise program.

Nonexercise energy expenditure and physical activity in the Midwest Exercise Trial 2

PURPOSE

This study aimed to examine compensatory changes in nonexercise energy expenditure (NEEx) and nonexercise physical activity (NEPA) in response to an aerobic exercise training program.

METHODS

Ninety-two overweight/obese (body mass index, 25-39.9 kg·m) sedentary young adults (18-30 yr) completed a 10-month randomized clinical efficacy trial of aerobic exercise 5 d·wk at either 400 kcal per session (n = 37), 600 kcal per 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 an accelerometer at months 0, 3.5, 7, and 10. NEEx was calculated by the following formula: [(total daily energy expenditure × 0.9) - RMR] - net EEEx (EEEx-RMR). Mixed modeling was used to examine differences between groups (group effect), within groups (time effect), and group-time interaction for NEEx and NEPA.

RESULTS

Within the exercise groups, there were no significant effects (all P > 0.05) of group, time, or group-time interaction for NEPA. In addition, there were no significant within- or between-group differences for change in NEEx. However, activity counts per minute were significantly higher (P < 0.001) in the 600-kcal-per-session group (346 ± 141 min·d) versus controls (290 ± 106 min·d) at month 7 and significantly higher (P < 0.001) in both the 600-kcal-per-session (345 ± 163 min·d) and 400-kcal-per-session groups (317 ± 146 min·d) versus controls (277 ± 116 min·d) at 10 months.

CONCLUSIONS

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.

Reciprocal Compensation to Changes in Dietary Intake and Energy Expenditure within the Concept of Energy Balance

An imbalance between energy intake and energy expenditure is the primary etiology for excess weight gain. Increased energy expenditure via exercise and energy restriction via diet are commonly used approaches to induce weight loss. Such behavioral interventions, however, have generally resulted in a smaller than expected weight loss, which in part has been attributed to compensatory adaptations in other components contributing to energy balance. Current research points to a loose coupling between energy intake and energy expenditure on a daily basis, and evidence for long-term adaptations has been inconsistent. The lack of conclusive evidence on compensatory adaptations in response to alterations in energy balance can be attributed to differences in intervention type and study population. Physical activity (PA) levels may be reduced in response to aerobic exercise but not in response to resistance exercise. Furthermore, athletic and lean adults have been shown to increase their energy intake in response to exercise, whereas no such response was observed in obese adults. There is also evidence that caloric restriction is associated with a decline in PA. Generally, humans seem to be better equipped to defend against weight loss than avoid weight gain, but results also show a large individual variability. Therefore, individual differences rather than group means should be explored to identify specific characteristics of "compensators" and "noncompensators." This review emphasizes the need for more research with simultaneous measurements of all major components contributing to energy balance to enhance the understanding of the regulation of energy balance, which is crucial to address the current obesity epidemic.

Active video games and energy balance in male adolescents: a randomized crossover trial

BACKGROUND

Active video games (AVGs) have been shown to acutely increase energy expenditure when compared with seated video games; however, the influence of AVGs on compensatory adjustments in energy intake and expenditure is largely unknown.

OBJECTIVE

The aim was to examine the acute effects of AVGs on energy intake and expenditure.

DESIGN

With the use of a randomized crossover design, 26 male adolescents (mean ± SD age: 14.5 ± 1.4 y) completed three 1-h experimental conditions: resting control, seated video game play (Xbox 360; Microsoft), and AVG play (Kinect Adventures on Xbox 360) followed by an ad libitum lunch. A validated food menu was used to assess food intake immediately after the conditions and for the remainder of the day, and a dietary record was used for the subsequent 3-d period. Energy expenditure was measured by using portable indirect calorimetry throughout each experimental condition, and an accelerometer was used to assess the subsequent 3-d period. Appetite sensations were assessed by using visual analog scales at different time points during the testing day. The primary outcomes were acute (immediately after the conditions and 24-h) and short-term (3-d) energy intake and expenditure.

RESULTS

Energy expenditure was significantly higher (~145%; P < 0.001) during the AVG condition than during the resting control and seated video game conditions; however, no significant differences in energy expenditure were observed 24 h (~6%; P > 0.49) and 3 d after the experimental conditions (~3%; P > 0.82). No significant differences were observed in absolute energy intake immediately after the conditions (~2%; P > 0.94) or in absolute energy intake 24 h (~5%; P > 0.63) and 3 d (~9%; P > 0.53) after the experimental conditions. Finally, appetite sensations were similar between conditions at all time points (P > 0.05).

CONCLUSIONS

The increase in energy expenditure promoted by a single session of Kinect AVG play is not associated with increased food intake but is compensated for after the intervention, resulting in no measurable change in energy balance after 24 h. These results suggest that the potential of Kinect to reduce the energy gap underlying weight gain is offset within 24 h in male adolescents. This trial was registered at clinicaltrials.gov as NCT01655901.

Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins

Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors.

Predictors of Energy Compensation during Exercise Interventions: A Systematic Review

Weight loss from exercise-induced energy deficits is usually less than expected. The objective of this systematic review was to investigate predictors of energy compensation, which is defined as body energy changes (fat mass and fat-free mass) over the total amount of exercise energy expenditure. A search was conducted in multiple databases without date limits. Of 4745 studies found, 61 were included in this systematic review with a total of 928 subjects. The overall mean energy compensation was 18% ± 93%. The analyses indicated that 48% of the variance of energy compensation is explained by the interaction between initial fat mass, age and duration of exercise interventions. Sex, frequency, intensity and dose of exercise energy expenditure were not significant predictors of energy compensation. The fitted model suggested that for a shorter study duration, lower energy compensation was observed in younger individuals with higher initial fat mass (FM). In contrast, higher energy compensation was noted for younger individuals with lower initial FM. From 25 weeks onward, energy compensation was no longer different for these predictors. For studies of longer duration (about 80 weeks), the energy compensation approached 84%. Lower energy compensation occurs with short-term exercise, and a much higher level of energy compensation accompanies long-term exercise interventions.

Facilitators and barriers to using treadmill workstations under real working conditions: a qualitative study in female office workers

PURPOSE

Characterize barriers and facilitators to use treadmill workstations in real work sites.

DESIGN

For 6 months, workers tried a sit-stand-walk treadmill workstation at will with expert ergonomic support. Qualitative data were collected monthly.

SETTING

Administrative and academic departments at a higher education institution in Massachusetts, United States.

PARTICIPANTS

Five female administrative office workers.

METHOD

One monthly group interview and one personal interview per participant during 6 months. Emerging topics from previous interviews were used in successive data gatherings. Transcribed data were manually coded according to the predefined topics of usability, comfort, safety, and productivity.

RESULTS

The setup of the work station, communication difficulties while walking (disrespectful, noisy), and peer pressure to maximize use were the main usability barriers. There was no event of falls. Trips were minimized. About comfort, subjects reported it hard to get used to prolonged standing position during the first month. Treadmill speed affected productivity mostly while drawing and working in spreadsheets. Lack of job autonomy was revealed as a generic barrier.

CONCLUSION

In this female group, treadmill workstations had serious design problems for workers with not enough control of their jobs. The early identification and removal of barriers likely needs to be considered when offering these workstations to workers with low job autonomy.

Does increased prescribed exercise alter non-exercise physical activity/energy expenditure in healthy adults? A systematic review

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.

Light physical activity is a better determinant of lower adiposity during the menopausal transition

OBJECTIVE

To investigate the relationship between time spent performing physical activity (PA) and adiposity across the menopausal transition.

METHODS

Body weight and body composition were analyzed in 65 women (47-54 years old; body mass index 23.2 ± 2.4 kg/m(2)) in a 5-year prospective study. Time spent in PA of varying intensities (sedentary, light, moderate and vigorous) was determined from 7-day accelerometer measurement and energy intake with a 7-day food diary.

RESULTS

Significant negative correlations were observed between the time spent in light-intensity PA and fat mass (FM) (r = -0.38, p < 0.005), central FM (r = -0.36, p < 0.005), peripheral FM (r = -0.33, p < 0.01), and percent body fat (r = -0.42, p < 0.001) at year 1, respectively. No significant correlations were noted between measures of adiposity and time spent performing either moderate or vigorous PA. Analyses using tertiles of time spent in light PA at year 1 showed that FM (20.7 ± 4.0 vs. 20.3 ± 6.6 vs. 16.6 ± 4.6 kg, p < 0.05), central FM (10.1 ± 2.6 vs. 10.0 ± 3.8 vs. 7.8 ± 2.4 kg; p < 0.05) and percent body fat (34.5 ± 5.1 vs. 32.2 ± 7.7 vs. 28.1 ± 6.2%, p < 0.01) were all significantly lower in women in the highest tertile. These differences remained significant after covariate analyses using time spent in moderate- and high-intensity PA and total energy intake. Finally, lower levels of FM, percent body fat, central and peripheral FM persisted in women who spent more time in light PA (highest tertiles) over the 5-year follow-up.

CONCLUSION

Our results suggest that the time spent performing light PA may have a greater impact on adiposity than moderate and/or vigorous PA, an observation independent of the menopausal status.

The ActivityStat hypothesis: the concept, the evidence and the methodologies

BACKGROUND

The ActivityStat hypothesis suggests that when physical activity is increased or decreased in one domain, there will be a compensatory change in another domain, in order to maintain an overall stable level of physical activity or energy expenditure over time. The ActivityStat debate is gaining momentum in the literature and most of the research to date is based on observational studies.

OBJECTIVE

The objective of this paper is to conceptually clarify the ActivityStat hypothesis and to examine the experimental research aiming to demonstrate or refute compensation using a systematic review process.

METHODS

A systematic review was conducted using electronic database searches with the aim of detecting studies experimentally investigating the ActivityStat hypothesis or compensation in physical activity or energy expenditure. Included studies were critically appraised using a specifically designed tool to address the conceptual considerations of the ActivityStat hypothesis.

RESULTS

Searches identified 28 studies that met the inclusion criteria. Publications spanned 26 years and had multiple methodological approaches, including randomized and non-randomized controlled trials, crossover designs, cluster randomized controlled trials and pre-post trials. Populations of the included studies ranged from children, to adults and the elderly, across a range of weight statuses and used both aerobic, resistance and mixed-exercise interventions. The timeframe of interventions ranged from 1 day to 4 years and outcomes were measured using doubly labelled water, accelerometry, heart rate monitoring, resting metabolic rate, indirect calorimetry, pedometry, subjective recall questionnaire and the activity-related time index. Fifteen of 28 included studies provided evidence of compensation, while 13 did not. Subgroup analyses by population, type and duration of intervention, weight status and study quality also showed mixed findings.

CONCLUSION

There is a substantial body of experimental literature investigating compensation that has largely been overlooked in the ActivityStat debate. However, this evidence is currently inconclusive and lacks a cohesive approach to the question of an ActivityStat. Recommendations for the design of future experimental research investigating the ActivityStat hypothesis are presented.

Unfavorable influence of structured exercise program on total leisure-time physical activity

In randomized controlled trials (RCTs), with customized structured physical exercise activity (SPEA) interventions, the dose of leisure-time physical activity (LTPA) should exceed the LTPA dose of the nonexercising control (C) group. This increase is required to substantiate health improvements achievable by exercise. We aimed to compare the dose of SPEA, LTPA, and total LTPA (SPEA + LTPA) between a randomized Nordic walking (NW) group, a power-type resistance training (RT) group, and a C group during a 12-week exercise intervention in obese middle-aged men (n = 144) with impaired glucose regulation. The dose of physical activity was measured with diaries using metabolic equivalents. No significant difference (P > 0.107) between the groups was found in volume of total LTPA. The volume of LTPA was, however, significantly higher (P < 0.050) in the C group than in the NW group, but not compared with the RT group. These results indicate that structured exercise does not automatically increase the total LTPA level, possibly, as a result of compensation of LTPA with structured exercise or spontaneous activation of the C group. Thus, the dose of total LTPA and the possible changes in spontaneous LTPA should be taken into account when implementing a RCT design with exercise intervention.

The effects of exercise during pregnancy on the newborn's brain: study protocol for a randomized controlled trial

BACKGROUND

It is generally accepted that an active lifestyle is beneficial for cognition in children, adults and the elderly. Recently, studies using the rat animal model found that the pups of mothers who exercised during pregnancy had increased hippocampal neurogenesis and better memory and learning abilities. The aim of this report is to present the experimental protocol of a study that is designed to verify if an active lifestyle during pregnancy in humans has an impact on the newborn's brain.

METHODS

60 pregnant women will be included in a randomized controlled study. The experimental group will be asked to exercise a minimum of 20 minutes three times per week, at a minimal intensity of 55% of their maximal aerobic capacity. The control group will not be exercising. The effect of exercise during pregnancy on the newborn's brain will be investigated 8 to 12 days postpartum by means of the mismatch negativity, a neurophysiological brain potential that is associated to auditory sensory memory. We hypothesize that children born to mothers who exercised during their pregnancy will present shorter latencies and larger mismatch negativity amplitudes, indicating more efficient auditory memory processes.

DISCUSSION

As of September 2011, 17 women have joined the study. Preliminary results show that the experimental group are active 3.1 ± 0.9 days per week while the control group only exercise 0.8 ± 0.6 days per week. The results of this study will present insight on fetal neuroplasticity and will be a valuable tool for health professionals who wish to encourage pregnant women to exercise.

TRIAL REGISTRATION

ClinicalTrials.gov registration: NTC01220778.

Impact of integrating a physical activity counsellor into the primary health care team: physical activity and health outcomes of the Physical Activity Counselling randomized controlled trial

The purpose of this paper was to report the physical activity and health outcomes results from the Physical Activity Counselling (PAC) trial. Patients (n = 120, mean age 47.3 ± 11.1 years, 69.2% female) who reported less than 150 min of physical activity per week were recruited from a large community-based Canadian primary care practice. After receiving brief physical activity counselling from their provider, they were randomized to receive 6 additional patient-centered counselling sessions over 3 months from a physical activity counsellor (intensive-counselling group; n = 61), or no further intervention (brief-counselling group; n = 59). Physical activity (self-reported and accelerometer) was measured every 6 weeks up to 25 weeks (12 weeks postintervention). Quality of life was also assessed, and physical and metabolic outcomes were evaluated in a randomly selected subset of patients (33%). In the intent-to-treat analyses of covariance, the intensive-counselling group self-reported significantly higher levels of physical activity at 6 weeks (p = 0.009) and 13 weeks (p = 0.01). There were no differences in self-reported physical activity between the groups after the intervention in the follow-up period, nor was there any increase in accelerometer-measured physical activity. Finally, the intensive-counselling patients showed greater decreases in percent body fat and total fat mass from 13 weeks to 25 weeks. Results for physical activity depended on the method used, with positive short-term results with self-report and no effects with the accelerometers. Between-group differences were found for body composition in that the intensive-counselling patients decreased more. A multisite randomized controlled trial with a longer intensive intervention and follow-up is warranted.

Acute and long-term effects of exercise on appetite control: is there any benefit for weight control?

PURPOSE OF REVIEW

To examine the relationship between energy intake, appetite control and exercise, with particular reference to longer term exercise studies. This approach is necessary when exploring the benefits of exercise for weight control, as changes in body weight and energy intake are variable and reflect diversity in weight loss.

RECENT FINDINGS

Recent evidence indicates that longer term exercise is characterized by a highly variable response in eating behaviour. Individuals display susceptibility or resistance to exercise-induced weight loss, with changes in energy intake playing a key role in determining the degree of weight loss achieved. Marked differences in hunger and energy intake exist between those who are capable of tolerating periods of exercise-induced energy deficit, and those who are not. Exercise-induced weight loss can increase the orexigenic drive in the fasted state, but for some this is offset by improved postprandial satiety signalling.

SUMMARY

The biological and behavioural responses to acute and long-term exercise are highly variable, and these responses interact to determine the propensity for weight change. For some people, long-term exercise stimulates compensatory increases in energy intake that attenuate weight loss. However, favourable changes in body composition and health markers still exist in the absence of weight loss. The physiological mechanisms that confer susceptibility to compensatory overconsumption still need to be determined.