Alterations in energy balance from an exercise intervention with ad libitum food intake

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.

Preliminary Validation of the Exercise-Snacking Licensing Scale: Rewarding Exercise with Unhealthy Snack Foods and Drinks

There is evidence that individuals’ compensatory health beliefs may be an important psychological driver of health behavior. Only recently, however, have researchers begun to develop and seek to validate instruments that are suited to measuring specific pairings of the diverse compensatory health beliefs that exist. The aim of this study was to provide support for key aspects of validity associated with the Exercise-Snacking Licensing Scale (ESLS), an instrument that was designed to assess individuals’ endorsement (or licensing) of unhealthy snacking behaviors around exercise. Participants (N = 1095) responded to a version of the ESLS that was designed to assess their licensing responses following either “light” or “tiring” physical activity, and completed additional instruments assessing dispositional, exercise-related, and diet-related constructs. Analyses indicated that scores derived from both versions of the ESLS (“light” and “tiring” physical activity) displayed a relatively consistent factor structure, favorable alpha coefficients, and meaningful correlations with variables that are theoretically aligned with licensing. Factor analytic procedures did, however, indicate that researchers may wish, in future, to consider the use (or not) of reverse-scored items within the ESLS. Together, these findings provide important insight into the structural, external, and generalizability aspects of validity for scores derived from the ESLS, and indicate that the ESLS may be a valuable instrument for the brief assessment of unhealthy licensing beliefs around exercise. Further use of the ESLS is encouraged to determine if and how these licensing beliefs actually influence subsequent snacking behaviors, and the potential downstream effects these beliefs may have in shaping health outcomes associated with exercise participation.

Exercise, energy balance and body composition

Activity-induced energy expenditure, as determined by the activity pattern including exercise, is the most variable component of daily energy expenditure. Here, the focus is on effects of exercise training on energy balance and body composition in subjects with a sedentary or light-active lifestyle. Then, exercise training induces an energy imbalance consistently lower than prescribed energy expenditure from exercise. Additionally, individual responses are highly variable and decrease in time. Combining the results from 23 exercise training studies in normal-weight, overweight, and obese subjects, varying in duration from 2 to 64 weeks, showed an average initial energy imbalance of about 2 MJ/day with an exponential decline to nearly zero after about 1 year. A compensatory increase in energy intake is the most likely explanation for the lower than expected effect of exercise on energy balance. Overall, exercise training results in a healthier body composition as reflected by a reduction of body fat, especially in overweight and obese subjects, with little or no long-term effect on body weight.

Testing the Feasibility and Preliminary Efficacy of an 8-Week Exercise and Compensatory Eating Intervention

The aim of this study was to evaluate the feasibility and preliminary efficacy of an intervention comprised of regular exercise alongside educational and motivational support for participants’ avoidance of unhealthy compensatory eating. Forty-five sedentary individuals were randomized to an 8-week exercise plus compensatory eating avoidance program (CEAP; n = 24), or an 8-week exercise intervention only (control; n = 21). The feasibility and preliminary efficacy of the intervention were assessed using quantitative measures and supplemented with written responses to open-ended questions. The CEAP workshop was well-received; however, self-reported use of some of the included behavior change strategies was lower than expected. Post-intervention, there was evidence of reduced self-reported compensatory eating for participants in the CEAP group but not controls, with CEAP participants also reporting greater use of coping plans relative to controls post-intervention. The exercise program had benefits for waist circumference, body fat percentage, blood pressure, and cardiovascular fitness; however, improvements were similar between groups. Taken together, the results of this study indicate that the CEAP is feasible and may reduce compensatory eating around exercise; however, this effect is small. Potential modifications to the CEAP are discussed within the paper.

Anaerobic metabolism induces greater total energy expenditure during exercise with blood flow restriction

PURPOSE

We investigated the energy system contributions and total energy expenditure during low intensity endurance exercise associated with blood flow restriction (LIE-BFR) and without blood flow restriction (LIE).

METHODS

Twelve males participated in a contra-balanced, cross-over design in which subjects completed a bout of low-intensity endurance exercise (30min cycling at 40% of [Formula: see text]) with or without BFR, separated by at least 72 hours of recovery. Blood lactate accumulation and oxygen uptake during and after exercise were used to estimate the anaerobic lactic metabolism, aerobic metabolism, and anaerobic alactic metabolism contributions, respectively.

RESULTS

There were significant increases in the anaerobic lactic metabolism (P = 0.008), aerobic metabolism (P = 0.020), and total energy expenditure (P = 0.008) in the LIE-BFR. No significant differences between conditions for the anaerobic alactic metabolism were found (P = 0.582). Plasma lactate concentration was significantly higher in the LIE-BFR at 15min and peak post-exercise (all P≤0.008). Heart rate was significantly higher in the LIE-BFR at 10, 15, 20, 25, and 30min during exercise, and 5, 10, and 15min after exercise (all P≤0.03). Ventilation was significantly higher in the LIE-BFR at 10, 15, and 20min during exercise (all P≤0.003).

CONCLUSION

Low-intensity endurance exercise performed with blood flow restriction increases the anaerobic lactic and aerobic metabolisms, total energy expenditure, and cardiorespiratory responses.

Low Energy Turnover of Physically Inactive Participants as a Determinant of Insufficient Mineral and Vitamin Intake in NHANES

Micronutrient requirements do not scale linearly with physical activity-related energy expenditure (AEE). Inactive persons may have insufficient micronutrient intake because of low energy intake (EI). We extracted data from NHANES 2003-2006 on 4015 adults (53 ± 18 years (mean ± SD), 29 ± 6 kg/m², 48% women) with valid physical activity (accelerometry) and food intake (2 × 24 h-dietary recall) measures. Total energy expenditure (TEE) was estimated by summing the basal metabolic rate (BMR, Harris-Benedict), AEE, and 10% of TEE for the thermic effect of food, to calculate the physical activity levels (PAL = TEE/BMR). Energy intake (EI) was scaled to match TEE assuming energy balance. Adjusted food intake was then analyzed for energy and micronutrient content and compared to estimated average requirements. The NHANES population was physically insufficiently active. There were 2440 inactive (PAL < 1.4), 1469 lightly to moderately active (PAL1.4 < 1.7), 94 sufficiently active (PAL1.7 < 2.0), and 12 very active participants (PAL ≥ 2.0). The inactive vs. active had significantly lower intake for all micronutrients apart from vitamin A, B12, C, K, and copper (p < 0.05). The inactive participants had insufficient intake for 6/19 micronutrients, while the active participants had insufficient intake for 5/19 (p < 0.05) micronutrients. Multiple linear regression indicated a lower risk for insufficient micronutrient intake for participants with higher PAL and BMI (p < 0.001). Symmetrical up-scaling of PAL and EI to recommended physical activity levels reduced the frequency of micronutrient insufficiencies. It follows that prevalence of insufficient micronutrient intake from food in NHANES might be partly determined by low energy turnover from insufficient PAL.

Metabolic Equivalent in Adolescents, Active Adults and Pregnant Women

“Metabolic Equivalent” (MET) represents a standard amount of oxygen consumed by the body under resting conditions, and is defined as 3.5 mL O₂/kg × min or ~1 kcal/kg × h. It is used to express the energy cost of physical activity in multiples of MET. However, universal application of the 1-MET standard was questioned in previous studies, because it does not apply well to all individuals. Height, weight and resting metabolic rate (RMR, measured by indirect calorimetry) were measured in adolescent males (n = 50) and females (n = 50), women during pregnancy (gestation week 35–41, n = 46), women 24–53 weeks postpartum (n = 27), and active men (n = 30), and were compared to values predicted by the 1-MET standard. The RMR of adolescent males (1.28 kcal/kg × h) was significantly higher than that of adolescent females (1.11 kcal/kg × h), with or without the effects of puberty stage and physical activity levels. The RMR of the pregnant and post-pregnant subjects were not significantly different. The RMR of the active normal weight (0.92 kcal/kg × h) and overweight (0.89 kcal/kg × h) adult males were significantly lower than the 1-MET value. It follows that the 1-MET standard is inadequate for use not only in adult men and women, but also in adolescents and physically active men. It is therefore recommended that practitioners estimate RMR with equations taking into account individual characteristics, such as sex, age and Body Mass Index, and not rely on the 1-MET standard.

Comparative accuracy of fitness tracking modalities in quantifying energy expenditure

The purpose of this study is to compare the accuracy of wrist-worn, consumer-grade pedometers and earbud sensor technology in quantifying energy expenditure. Nineteen participants (24.6 ± 3.1 years) performed 5 min exercise stages on a treadmill (80.5 m/min, 107.3 m/min, 134.1 m/min and 160.9 m/min) while measuring energy expenditure via the Fitbit Charge pedometer and Jabra Sport Pulse Wireless Earbuds, comparing with indirect calorimetry. Paired samples t-tests were used to calculate differences and Pearson correlations to examine associations between kcals measured from the Fitbit and Jabra earbuds from indirect calorimetry. Results indicate significant underestimations of kcals for both devices at all speeds except one (Jabra earbuds at 107.3 m/min). Moderate correlations were observed for the Fitbit at 107.3 m/min and 107.3 m/min, and 134.1 m/min for the Jabra earbuds. Both devices considerably underestimated kcals, suggesting that caution be used when incorporating such data into fitness/health goals.