Exercise-induced Energy Expenditure Research Articles

Energy compensation after an aerobic exercise session in high-fat/low-fit and low-fat/high-fit young male subjects

There is general agreement that exercise-induced energy expenditure is not entirely compensated for at the next meal or over the following 24 h, but inter-individual variability is high. The role of ‘fatness and fitness’ in this variability has never been assessed. Therefore, eighteen non-obese male subjects aged 22·2 (sd 2·0) years were selected and separated into a ‘high-fatness and low-fitness’ (Hfat/Lfit, n 9) and a ‘low-fatness and high-fitness’ (Lfat/Hfit, n 9) group, according to three criteria: maximal oxygen uptake; weekly hours of physical activity; fat mass index. At 1 h before lunch, they were subjected to 60 min of exercise on a cycle ergometer (70 % VO2max), or stayed at rest. Then, they self-reported food intake in diaries until the next breakfast. Intake at lunch was not different between conditions, but was higher after exercise than after rest over the 24 h, leading to a significant but partial mean level of compensation of 49·8 (sem 16·5) and 37·8 (sem 24·6) % for the Hfat/Lfit and Lfat/Hfit groups, respectively. Energy compensation at lunch and over the 24 h were strongly correlated (r 0·76, P< 0·001). Both groups consumed more fat and protein after exercise than after rest over the 24 h, but the percentage of energy derived from fat increased only in the Hfat/Lfit group (2·1 (sem 0·6) %, P= 0·026). Thus, the energy cost of an aerobic exercise session was partially compensated over the next 24 h independently of the ‘fatness and fitness’ status, but ‘high-fat and low-fit’ individuals compensated more specifically on fats.

Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise—a randomized controlled trial in overweight sedentary males

The amount of weight loss induced by exercise is often disappointing. A diet-induced negative energy balance triggers compensatory mechanisms, e.g., lower metabolic rate and increased appetite. However, knowledge about potential compensatory mechanisms triggered by increased aerobic exercise is limited. A randomized controlled trial was performed in healthy, sedentary, moderately overweight young men to examine the effects of increasing doses of aerobic exercise on body composition, accumulated energy balance, and the degree of compensation. Eighteen participants were randomized to a continuous sedentary control group, 21 to a moderate-exercise (MOD; 300 kcal/day), and 22 to a high-exercise (HIGH; 600 kcal/day) group for 13 wk, corresponding to ∼30 and 60 min of daily aerobic exercise, respectively. Body weight (MOD: -3.6 kg, P < 0.001; HIGH: -2.7 kg, P = 0.01) and fat mass (MOD: -4.0 kg, P < 0.001 and HIGH: -3.8 kg, P < 0.001) decreased similarly in both exercise groups. Although the exercise-induced energy expenditure in HIGH was twice that of MOD, the resulting accumulated energy balance, calculated from changes in body composition, was not different (MOD: -39.6 Mcal, HIGH: -34.3 Mcal, not significant). Energy balance was 83% more negative than expected in MOD, while it was 20% less negative than expected in HIGH. No statistically significant changes were found in energy intake or nonexercise physical activity that could explain the different compensatory responses associated with 30 vs. 60 min of daily aerobic exercise. In conclusion, a similar body fat loss was obtained regardless of exercise dose. A moderate dose of exercise induced a markedly greater than expected negative energy balance, while a higher dose induced a small but quantifiable degree of compensation.

Discussion of “Overweight and obese boys reduce food intake in response to a glucose drink but fail to increase intake in response to exercise of short duration”

Tamam and collaborators recently proposed an interesting paper addressing the food intake and appetite response to an acute exercise and a glucose drink in normal weight and overweight–obese adolescents (Tamam et al. 2012). This paper adds great and useful results to the actual literature but to our mind some issues have to be underlined. The authors state that their paper is the first to provide data regarding the impact of acute effect of short exercise on energy intake in 9to 14-year-old boys while previous recent studies have explored the impact of three 10-min bouts of exercise (Thivel et al. 2011a, 2011b, 2012b). In this paper, overweight–obese adolescent boys do not modify their energy intake after a 15min bout of exercise set at their ventilatory threshold, whereas it has been shown that acute intensive exercise (>70% maximal oxygen consumption) was able to induce a decrease energy intake in such a population at the following ad libitum meal (Thivel et al. 2011a, 2011b, 2012b). The important exercise-induced energy expenditure differences between those last studies (about 300 kcal) and the present one (63 ± 7 kcal) may explain such a discrepancy, but we recently suggested that the energy expended during exercise does not explain the subsequent energy consumption since food intake was differentially affected after isoenergetic exercises at 2 levels of intensity (40% and 75% maximal oxygen consumption) (for review see Thivel et al. 2012a, 2012b). To our view the main reasons that Tamam et al. did not find any differences are the short duration of the follow-up, dinner energy intake was not examined, and most importantly, the use of ad libitum pizza buffets that are highly palatable and could have favoured inconsistent energy intake in those youths. In our previous work, we chose buffet meals composed of a high diversity of food without the participant’s preferred items to avoid the hedonic influence on food intake. The “non-homeostatic” regulation of energy intake certainly overpasses the physiological pathways involved in presence of highly palatable items (Finlayson and Dalton 2012). An important decreased food intake at dinner time without appetite modification (about 7 h after the exercise session) has also been reported by our group, whereas Tamam and colleagues suggested that the increased appetite sensation observed after exercise could favour higher energy consumption later in the day. Based on the already shown uncoupling effect of exercise on subjective appetite and effective energy consumption in both adults and youths (Flint et al. 2000; Mattes 1990; Thivel et al. 2011a, 2012b), it appears difficult to formulate such a hypothesis. Finally, the authors conclude that an acute short-term exercise set at the ventilator threshold was able to reduce energy balance because of energy expenditure and in the absence of subsequent energy intake compensation. However, the covered period in which to assess energy balance seems too short to hypothesize so (which was pointed out by the authors) as compensatory trends have been underlined in overweight– obese children who decrease their spontaneous energy expenditure after such an exercise for the rest of the day (Kriemler et al. 1999; Thivel et al. 2012a, 2012b). This compensatory response leads once more to the consideration of whether the best impact of physical activity for weight control and weight loss remains the induced energy expenditure or its impact on energy intake (Chaput and Sharma 2011). The paper proposed by Tamam and collaborators provides then interesting results concerning the impact of a glucose drink on food intake in lean and overweight–obese youths but the interpretation of their data on the energy in-

Acute Exercise and Subsequent Nutritional Adaptations

The imbalance between energy expenditure and energy intake is the main factor accounting for the progression of obesity. For many years, physical activity has been part of weight-loss programmes to increase energy expenditure. It is now recognized that exercise can also affect appetite and energy consumption. In the context of seeking new obesity treatments, it is of major interest to clarify the impact of physical exercise on energy intake. Many reviews on this topic have been published regarding both lean and overweight adults, and this review focuses on the relationships between acute exercise and the short-term regulation of energy intake in lean and overweight or obese youths. The current literature provides very few data regarding the impact of exercise on subsequent energy intake and perceived and measured appetite in children and adolescents, mainly because of methodological difficulties in the assessment of both energy intake and expenditure. It has been long suggested that energy intake was regulated after exercise in order to compensate for the exercise-induced energy expenditure and then preserve energy balance. This overview underlines that the energy expended during exercise is not the main parameter that influences subsequent energy intake in both lean and overweight/obese children and adolescents, and that factors such as the duration or intensity of exercise may have larger impact. The effects of acute exercise on the following nutritional adaptations (energy intake and appetite feelings) remain inconclusive in lean youths, mainly due to the lack of data and the disparity of the methodologies used. Studies in overweight or obese children and adolescents are confronted with the same difficulties, and the few available data suggest that intensive exercise (>70% maximal oxygen consumption) can induce a reduction in daily energy balance, as a result of its anorexigenic effect in obese adolescents. However, further studies are needed to clarify the impact of acute exercise on subsequent nutritional adaptations and appetite-related hormones in children and adolescents, and to investigate the effect of chronic exercise programmes.

Energy intake and appetite following netball exercise over 5 days in trained 13–15 year old girls

Free-living energy intake and subjective appetite were monitored in a group of eleven 13–15-year old trained adolescent netball players. During preliminary visits, a FLEX heart rate calibration and resting metabolic test were conducted. Heart rate data were collected during a netball exercise session and sedentary period and during the waking hours of all study days, to enable exercise-induced and 24-h energy expenditure to be quantified. The girls completed two 5-day treatment weeks, interspersed with a 2-week ‘wash out’ period. A 47-min bout of netball exercise or an equivalent sedentary period was carried out on day 3 of each treatment week. Energy intake was measured over each 5-day period using a combined self-reported, weighed, food diary and 24-h recall interview technique. Subjective appetite (hunger, prospective food consumption, fullness) and mood were rated by subjects immediately before and after meals each day, and before and after the netball exercise and the sedentary period. Forty eight hour energy intake was significantly higher following the netball exercise compared to the sedentary period. The girls felt significantly more hungry immediately following the netball exercise compared to immediately before. In conclusion, a single intermittent exercise bout alters subsequent appetite and energy intake in trained 13–15-year old girls.

The influence of physical activity on appetite control: an experimental system to understand the relationship between exercise-induced energy expenditure and energy intake

Investigations of the impact of physical activity on appetite control have the potential to throw light on the understanding of energy balance and therefore, upon body weight regulation and the development of obesity. Given the complexity of the landscape influencing weight regulation,research strategies should reflect this complexity. We have developed a research approach based on the concept of the psychobiological system (multi-level measurement and analysis) and an experimental platform that respects the operations of an adaptive regulating biological system. It is important that both sides of the energy balance equation (activity and diet) receive similar detailed levels of analysis. The experimental platform uses realistic and fully supervised levels of physical activity, medium-term (not acute) interventions, measurement of body composition, energy metabolism (indirect calorimetry), satiety physiology(gut peptides), homeostatic and hedonic processes of appetite control, non-exercise activity, obese adult participants and both genders. This research approach has shown that the impact of physical activity on appetite control is characterised by large individual differences. Changes in body composition, waist circumference and health benefits are more meaningful than changes in weight. Further, we are realising that the acute effects do not predict what will happen in the longer term. The psychobiological systems approach offers a strategy for simultaneously investigating biological and behavioural processes relevant to understanding obese people and how obesity can be managed. This experimental platform provides opportunities for industry to examine the impact of foods under scientifically controlled conditions relevant to the real world.

Beneficial effects of exercise: shifting the focus from body weight to other markers of health*

Background: Exercise is widely promoted as a method of weight management, while the other health benefits are often ignored. The purpose of this study was to examine whether exercise-induced improvements in health are influenced by changes in body weight. Methods: Fifty-eight sedentary overweight/obese men and women (BMI 31.8 (SD 4.5) kg/m2 ) participated in a 12-week supervised aerobic exercise intervention (70% heart rate max, five times a week, 500 kcal per session). Body composition, anthropometric parameters, aerobic capacity, blood pressure and acute psychological response to exercise were measured at weeks 0 and 12. Results: The mean reduction in body weight was -3.3 (3.63) kg (p&lt;0.01). However, 26 of the 58 participants failed to attain the predicted weight loss estimated from individuals’ exercise-induced energy expenditure. Their mean weight loss was only -0.9 (1.8) kg (p&lt;0.01). Despite attaining a lower-than-predicted weight reduction, these individuals experienced significant increases in aerobic capacity (6.3 (6.0) ml/kg/min; p&lt;0.01), and a decreased systolic (-6.00 (11.5) mmHg; p&lt;0.05) and diastolic blood pressure (-3.9 (5.8) mmHg; p&lt;0.01), waist circumference (-3.7 (2.7) cm; p&lt;0.01) and resting heart rate (-4.8 (8.9) bpm, p&lt;0.001). In addition, these individuals experienced an acute exercise-induced increase in positive mood. Conclusions: These data demonstrate that significant and meaningful health benefits can be achieved even in the presence

Comparison Of Two Portable Devices For Assessing Energy Expenditure During High-intensity Running

One of the main challenges of exercise nutrition is to ensure that athletes keep their energy intake and energy expenditure (EE) within healthy limits. Therefore, correct methods to quantify EE are necessary. Exercise-induced EE can be measured reliably with indirect calorimetry (IC) under laboratory conditions but the quantification of EE in the field is more challenging. Portable devices such as the Sensewear Pro3 armband (SENS; BodySense, USA) and the Actiheart monitor (ACTI; CamNtech, UK) have been designed for simple EE assessment on a daily basis. These devices have been validated in the general population but their performance has not been studied adequately during high-intensity exercise. PURPOSE: To compare energy expenditure measured with SENS and ACTI with an accepted reference method (IC) during high-intensity running. METHODS: Twenty-nine male participants (27.2 ± 1.9 y, 184 ± 7 cm, 79.8 ± 7.6 kg) performed a running test, which started at 2.8 m/s. Every 5 minutes, velocity was increased by 0.4 m/s until 4.8 m/s or voluntary exhaustion. During the test, the participants simultaneously wore SENS and ACTI. IC was performed with a ZAN 600 spirograph (Zan, Germany). RESULTS: EE measured with SENS was moderately correlated with IC values (r = 0.68). For running speeds greater or equal 3.2 m/s EE obtained with SENS was significantly smaller than reference data. The difference increased from 1.0 ± 1.0 METs at 3.2 m/s to 4.8 ± 1.7 METs at 4.8 m/s (p < 0.001). Underestimation was minimal before the test (0.2 ± 0.9 METs) but significant post-exercise (3.7 ± 2.9 METs, p < 0.001). For ACTI, there was also a moderate correlation with IC values (r = 0.77). ACTI underestimated EE between 0.9 ± 1.2 METs (2.8 m/s) and 4.3 ± 1.9 METs (4.8 m/s) and also during rest periods (before: 0.5 ± 0.4 METs, after: 4.1 ± 3.0 METs). The level of underestimation grew significantly with increasing EE (p < 0.001). CONCLUSIONS: Both devices performed similarly during the high-intensity running trial. SENS and ACTI underestimated ExEE and the level of underestimation increased significantly with increasing running velocities. However, the correlation with the IC data indicates that the application of exercise-specific should improve the validity of both devices.

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

Objective Walking is commonly recommended to help with weight management. We measured total energy expenditure (TEE) and its components to quantify the impact of increasing exercise-induced energy expenditure (ExEE) on other components of TEE. Methods Thirteen obese women underwent an 8-week walking group intervention. TEE was quantified using doubly labeled water, ExEE was quantified using heart rate monitors, daily movement was assessed by accelerometry and resting metabolic rate was measured using indirect calorimetry. Results Four of the 13 participants achieved the target of 1500 kcal wk −1 of ExEE and all achieved 1000 kcal wk −1. The average ExEE achieved by the group across the 8 weeks was 1434 ± 237 kcal wk −1. Vigorous physical activity, as assessed by accelerometry, increased during the intervention by an average of 30 min per day. Non-exercise activity thermogenesis (NEAT) decreased, on average, by 175 kcal d −1 (−22%) from baseline to the intervention and baseline fitness was correlated with change in NEAT. Conclusions Potential alterations in non-exercise activity should be considered when exercise is prescribed. The provision of appropriate education on how to self-monitor daily activity levels may improve intervention outcomes in groups who are new to exercise. Practice implications Strategies to sustain incidental and light physical activity should be offered to help empower individuals as they develop and maintain healthy and long-lasting lifestyle habits.

Regulation of Energy Balance during Long-Term Physical Inactivity Induced by Bed Rest with and without Exercise Training

Short-term physical inactivity affects energy balance and is considered conducive to weigh gain. Long-term effects are unknown. The objective of the study was to use a bed-rest model to determine the long-term effects of physical inactivity on energy balance regulation and test the effect of exercise training on energy balance adjustment to physical inactivity. Sixteen lean women were divided into two groups (n = 8 each): a control group subjected to a strict 60-d bed rest and an exercise group subjected to a combined aerobic/resistive exercise training concomitantly to bed rest. Body composition, spontaneous energy intake, hunger, total energy expenditure (TEE), and fasting gut hormones were measured. Based on bed-rest-induced body composition changes, the control group were in slight negative energy balance (-0.4 +/- 0.4 MJ/d; P = 0.01 vs. zero), essentially due to muscle atrophy (P < 0.001 vs. zero). The stable fat mass (P = 0.19 vs. zero), and the matching between spontaneous energy intake and TEE indicated, however, a stable energy balance. Hunger and gut hormones remained unchanged during the bed rest. In the exercise group, TEE was 24% higher than in the control group (P = 0.004). Unexpectedly, desire to consume food (P = 0.025) decreased and spontaneous energy intake (P = NS) was not stimulated, promoting a negative energy balance (-1.1 +/- 0.5 MJ/d, P = 0.0003 vs. zero). Energy balance is regulated during 2 months of physical inactivity, contrasting with short-term experiments. Conversely, exercise-induced energy expenditure in bed-resting subjects who have no spontaneous physical activity did not induce hunger and promoted a negative energy balance, suggesting a potential role of nonexercise physical activities in energy balance regulation.

Beneficial effects of exercise: shifting the focus from body weight to other markers of health

Background:Exercise is widely promoted as a method of weight management, while the other health benefits are often ignored. The purpose of this study was to examine whether exercise-induced improvements in...

Acute compensatory eating following exercise is associated with implicit hedonic wanting for food

The efficacy of exercise to promote weight loss could potentially be undermined by its influence on explicit or implicit processes of liking and wanting for food which in turn alter food preference. The present study was designed to examine hedonic and homeostatic mechanisms involved in the acute effects of exercise on food intake. 24 healthy female subjects were recruited to take part in two counterbalanced activity sessions; 50 min of high intensity (70% max heart rate) exercise (Ex) or no exercise (NEx). Subjective appetite sensations, explicit and implicit hedonic processes, food preference and energy intake (EI) were measured immediately before and after each activity session and an ad libitum test meal. Two groups of subjects were identified in which exercise exerted different effects on compensatory EI and food preference. After exercise, compensators (C) increased their EI, rated the food to be more palatable, and demonstrated increased implicit wanting. Compensators also showed a preference for high-fat sweet food compared with non-compensators (NC), independent of the exercise intervention. Exercise-induced changes in the hedonic response to food could be an important consideration in the efficacy of using exercise as a means to lose weight. An enhanced implicit wanting for food after exercise may help to explain why some people overcompensate during acute eating episodes. Some individuals could be resistant to the beneficial effects of exercise due to a predisposition to compensate for exercise-induced energy expenditure as a result of implicit changes in food preferences.

Aerobic fitness does not modulate protein metabolism in response to increased exercise: a controlled trial

BackgroundA sudden increase in exercise and energy expenditure is associated with an increase in protein turnover and nitrogen excretion. This study examined how a sudden increase in exercise-induced energy expenditure affected whole body protein metabolism and nitrogen balance in people of differing levels of aerobic fitness. We hypothesized that alterations in whole-body protein turnover would be attenuated, and nitrogen balance would be preserved, in individual with higher levels of aerobic fitness.MethodsEleven men, categorized as either having a lower (LOW-FIT; n = 5) or higher (FIT; n = 6) aerobic fitness level, completed a 4-d baseline period (BL) of an energy balance diet while maintaining usual physical activity level, followed by a 7-d intervention consisting of 1,000 kcal·d-1 increased energy expenditure via exercise (50–65% VO2peak). All volunteers consumed 0.9 g protein·kg-1·d-1 and total energy intake was adjusted to maintain energy balance throughout the 11-d study. Mean nitrogen balance (NBAL) was determined for BL, days 5–8 (EX1), and days 9–11 (EX2). Whole-body protein turnover was derived from phenylalanine and tyrosine kinetics assessed while fasting at rest on days 4, 7, and 12 using a priming dose of L-[ring-15N]tyrosine and a 4-h primed, continuous infusion of L-[15N]phenylalanine and L-[ring-2H4]tyrosine.ResultsA significant main effect of time indicated that NBAL increased over the course of the intervention; however, a group-by-time interaction was not observed. Although FIT demonstrated a lower net protein oxidation and higher net protein balance compared to LOW-FIT, neither the effect of time nor a group-by-time interaction was significant for Phe flux, net protein oxidation, or derived whole-body protein synthesis and net protein balance.ConclusionThe absence of significant group-by-time interactions in protein metabolism (i.e., NBAL and whole-body protein turnover) between LOW-FIT and FIT males suggest that aerobic fitness level does not modulate protein "sparing" in response to an unaccustomed increase in energy expenditure.

Energy intake and appetite following exercise in lean and overweight girls

Twelve 11-year-old girls (six lean, six overweight) were given meals in the laboratory and at school for 5 days, with exercise imposed for 2 days and sedentary activities on another 2 days in counterbalanced sequences. During a preliminary visit, the FLEX heart rate method was used to predict individual exercise durations eliciting 1.5MJ energy expenditure. Morning and afternoon cycling exercise was subsequently imposed in the laboratory on 2 consecutive days as part of the 5-day intervention. Energy intake was measured via observation with meals being standardised between conditions, prepared and weighed by the research team. Hunger, fullness and desire to eat were rated by subjects immediately before and after meals and exercise. Energy expenditure was significantly elevated in the exercise condition, compared to sedentary. No exercise-induced differences in total daily or 5-day total energy intake were observed between groups or treatments. Overweight girls, however, rated their appetite immediately after exercise as being stronger than they rated it before exercise. In response to exercise-induced energy expenditure, 11-year old overweight and lean girls did not elevate their energy intake over a 5-day period.

Moderate Exercise-Induced Energy Expenditure Does Not Alter Leptin Levels in Sedentary Obese Men

The purpose of the study was to determine whether exercise-induced increases in energy expenditure (EE) alter circulating leptin levels in obese individuals. Participants were randomized to an exercise intervention group (n = 8) or nonexercising control (n = 7). All data were collected on an outpatient basis at the exercise physiology laboratory at the University of Central Florida. Fifteen healthy obese males (24.9 +/- 1.4 years old, body mass index 33.4 +/- 0.7 kg . m). Members of the intervention group underwent a single exercise session of moderate intensity (58.4 +/- 1.3% of VO2max) for 60 minutes. Postexercise, 24 hour postexercise, and 48 hour postexercise levels of leptin, insulin, and ghrelin. The exercise session elicited an EE of 567 +/- 25 Kcal. No significant main effect or time-by-group interactions for leptin or ghrelin were observed immediately after the exercise bout or in the days following the intervention. These preliminary data suggest that a bout of acute exercise of moderate intensity and duration does not affect leptin concentration. It is possible that a higher level of EE is required to elicit substantial changes.

Improvements in glucose tolerance and insulin action induced by increasing energy expenditure or decreasing energy intake: a randomized controlled trial

Weight loss, through calorie restriction or increases in energy expenditure via exercise, improves glucose tolerance and insulin action. However, exercise-induced energy expenditure may further improve glucoregulation through mechanisms independent of weight loss. The objective was to assess the hypothesis that weight loss through exercise-induced energy expenditure improves glucoregulation and circulating factors involved in insulin action to a greater extent than does similar weight loss through calorie restriction. Sedentary men and women aged 50-60 y with a body mass index (kg/m(2)) of 23.5-29.9 were randomly assigned to 1 of 2 weight-loss interventions [12 mo of exercise training (EX group; n = 18) or calorie restriction (CR group; n = 18)] or to a healthy lifestyle (HL) control group (n = 10). The insulin sensitivity index and areas under the curve for glucose and insulin were assessed with an oral-glucose-tolerance test. Adiponectin and tumor necrosis factor alpha concentrations were measured in fasting serum. Fat mass was measured by dual-energy X-ray absorptiometry. Yearlong energy deficits were not significantly different between the EX and CR groups, as evidenced by body weight and fat mass changes. The insulin sensitivity index increased and the glucose and insulin areas under the curve decreased in the EX and CR groups, remained unchanged in the HL group, and did not differ significantly between the EX and CR groups. Marginally significant increases in adiponectin and decreases in the ratio of tumor necrosis factor alpha to adiponectin occurred in the EX and CR groups but not in the HL group. Weight loss induced by exercise training or calorie restriction improves glucose tolerance and insulin action in nonobese, healthy, middle-aged men and women. However, it does not appear that exercise training-induced weight loss results in greater improvements than those that result from calorie restriction alone.

Prescribing Aerobic Exercise for the Regulation of Postprandial Lipid Metabolism

Prolonged presence of elevated plasma triglycerides (TGs) during the postprandial period has been suggested to increase the risk for coronary artery disease. Aerobic exercise attenuates postprandial lipaemia and this has generally been described as a short-term effect of the exercise. Effects of exercise on postprandial lipaemia have mostly been investigated, and documented, with large exercise-induced energy expenditures (i.e. 1000 kcal). The exact mechanisms involved in the attenuation of postprandial lipaemia with exercise are not completely understood, but it appears that at least two mechanisms are involved: a decrease in TG secretion by the liver and an increase in plasma TG clearance by the muscle. Changes in the metabolism of other lipids, such as those in high-density lipoprotein cholesterol, have been documented only when the exercise is performed some hours before the fat meal. Although factors such as the physical fitness and percentage body fat of an individual are likely to also be involved, the most important factors determining the magnitude of the attenuation in postprandial lipaemia appear to be the magnitude of the exercise-induced energy expenditure and the intensity of exercise. To date, the evidence suggests that healthy individuals can generally induce favourable changes in postprandial lipaemia with aerobic exercise that: (i) is completed during the period extending from 16 hours before a meal through 1.5 hours after a meal; (ii) is of moderate intensity; and (iii) results in an energy expenditure of approximately 500 kcal (or more).

長期の運動習慣を有する中年女性におけるエネルギー消費量, 体組成および最大酸素摂取量

The purpose of this study was to examine the effects of long-term habitual exercise on daily total energy expenditure (TEE) and its components, body composition and maximal oxygen uptake (VO2max) in middle-aged Japanese women. Twenty-eight subjects aged 39 to 58 years were assigned either to a nonhabitual exercise group (Control ; n=12) or a habitual exercise group (Exercise ; n=16). TEE, physical activity level (PAL) and the daily physical activity energy expenditure (PAEE) were assessed by doubly labeled water (DLW) method. The exercise-induced energy expenditure (ExEE) and nonexercise-induced energy expenditure (NExEE) were evaluated based on the activity record investigation conducted simultaneously during the DLW measurement period. The result follows that TEE was significantly (p<0.01) higher in the Exercise group (2520 kcal · day-1) than in the Control group (1921 kcal · day-1). There was no significant difference in basal metabolic rate between the groups. PAEE and ExEE were significantly higher in the Exercise group than in the Control group (p<0.01). Habitual exercise induced an increase in TEE without resulting in a compensatory reduction of NExEE. The percentage body fat (fat%) was significantly lower in the Exercise group (25.5%) than in the Control group (30.9%). VO2max was higher in the Exercise group (1788 ml · min-1) than in the Control group (1417 ml. min-1). After correction for body weight, fat% was negatively associated with TEE (p<0.01), PAEE (p<0.01) and ExEE (p=0.05), while VO2max was positively associated with TEE (p<0.05), PAL (p<0.05), PAEE (p<0.05) and ExEE (p<0.01). These results suggest that habitual exercise is associated with the increase of TEE, the improvement of body composition and VO2max. The improvement of VO2max was mainly caused by the increase in ExEE, indicating that the exercise intensity is important to the improvement of cardiorespiratory endurance fitness.

Short-term appetite and energy intake following imposed exercise in 9- to 10-year-old girls

Short-term effects of different intensities of exercise-induced energy expenditure on energy intake and hunger were compared in 19 girls (10.0±0.6 years) in three conditions: sedentary, low-intensity exercise and high-intensity exercise. The exercise conditions involved cycling at 50 and 75% of peak oxygen uptake, respectively, but were designed to evoke approximately 1.50 MJ of total expenditure, as estimated from continuously monitored heart rate. A maintenance breakfast of controlled energy intake was provided and ad libitum energy intake was measured at lunch and dinner. Differences in energy intake relative to expenditure, between 09:30 and 17:00, were calculated by subtracting energy expenditure from energy intake (energy difference). Hunger, fullness and prospective consumption were rated before and after meals and exercise sessions. Lunch energy intake was significantly less after low-intensity exercise than after high-intensity exercise. Energy expenditure was greater in the exercise conditions than when sedentary and the energy difference was more positive in the sedentary condition than in each of the exercise conditions. At mid-afternoon, rated prospective consumption was less after the high-intensity exercise. The imposition of energy expenditure through exercise of either low or high intensity resulted in no detectable increase in energy intake in the short term.

What processes are involved in the appetite response to moderate increases in exercise-induced energy expenditure?

It is intuitive that an energy deficit induced by exercise induces an automatic increased drive for food (hunger and energy intake). However, the absence of a compensatory increase in energy intake (EI) in response to an exercise-induced increase in energy expenditure (EE) is now well documented. Thus, there is a weak coupling between exercise-induced increases in EE and EI. One paradox related to the phenomenon of a weak coupling between the exercise-induced EE and EI is the observation of a positive relationship between physical activity and food intake in the long-term free-living situation (i.e. tight coupling between EE and EI). It is possible, therefore, that a period of transition (uncoupling) occurs in the short-term, before a steady-state (coupling) condition is achieved. It is likely that a combination of physiological and behavioural adaptations occur in order to achieve a tight coupling between EE and EI. The precise physiological and behavioural changes that take place to obtain a new equilibrium (i.e. coupling between EE and EI) are still undetermined. The expectation that exercise-induced increases in EE should drive up hunger and food intake tends to be based on the concept of a strong coupling between physiology and behaviour. However, because of the individual's strong volitional control over eating behaviour, the psychological influences on the appetite response to exercise should not be undervalued. The psychological position of the individual (e.g. dietary restraint, food-related cognitions, reasons for exercising) could have a very strong influence on the food intake response to exercise. Misjudgements concerning the energy value of the food (EI) relative to the energy value of the exercise (EE) could be one possibility why exercise fails to be a successful method of weight loss for some individuals.