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The available literature on heat pumps shows that thermodynamic models lead to minimization of energy expense, very often in endoreversible configurations, sometimes irreversibles. The present paper purpose is to revisit and complete the heat pumps irreversible model by adding the coupling constraint between the cycle and the thermal reservoirs assumed to be thermostats. This constraint is in fact an essential condition for the cycle existence, practically always ignored. This modeling leads to a set of new results, including new expressions for the COP corresponding to minimum energy expense. The fundamental consequences of this new approach also show the limits of the equipartition theorem of heat exchange area, as well as of the entropy minimization method (EGM). [ABSTRACT FROM AUTHOR]

Summary Objectives To validate accelerometer counts against oxygen uptake in 9 to 11 years old children performing a number of highly variable physical activities and to determine accelerometer cut-off points for sedentary behavior, light, moderate, and vigorous physical activities. Equipment and methods Eight boys and 6 girls aged 9 to 11 years old (height: 1.40 ± 0.06 m, body mass: 33.5 ± 5.1 kg, BMI: 16.9 ± 2.0 kg/m2, body fat: 17.0 ± 4.8%, estimated VO 2 max: 50.85 ± 4.8 ml.kg−1.min−1) volunteered to participate in this study. They performed eight activities of different intensity namely watching TV, arts-crafts, slow and brisk forward walking, slow backward walking, forward running, aerobics and step-ups while VO 2 and counts were determined using indirect calorimetry and accelerometer, respectively. Results A highly significant correlation was found between accelerometer counts and VO 2 (r = 0.86, P < 0.01). Significant differences were observed between predicted and measured VO2 for ART, SWB and Aerobic activities (P = 0.0003; P < 0.0001 and P = 0.0004, respectively). Bland and Altman plot revealed no significant bias for all other activities (−0.6 ml.kg−1.min−1, P = 0.347) with 95% limits of agreement (LoA) ± 9.7 ml.kg−1.min−1. In addition, watching TV and participating in art activities were classified as sedentary activities (< 61 counts. min−1), slow walking forward was classified as light activity (61–3435 counts. min−1), slow backward walking, brisk walking and aerobics were classified as moderate activities (3436–6100 counts. min−1) and step-ups and running were defined as vigorous activities (≥ 6101 counts. min−1). [ABSTRACT FROM AUTHOR]

While hot yoga has gained enormous popularity in recent years, owing in part to increased environmental challenge associated with exercise in the heat, it is not clear whether hot yoga is more vigorous than thermo-neutral yoga. Therefore, the aim of this study was to determine objective and subjective measures of exercise intensity during constant intensity yoga in a hot and thermo-neutral environment. Using a randomized, crossover design, 14 participants completed 2 identical ∼20-min yoga sessions in a hot (35.3 ± 0.8 °C; humidity: 20.5% ± 1.4%) and thermo-neutral (22.1 ± 0.2 °C; humidity: 27.8% ± 1.6%) environment. Oxygen consumption and heart rate (HR) were recorded as objective measures (percentage of maximal oxygen consumption and percentage of maximal HR (%HRmax)) and rating of perceived exertion (RPE) was recorded as a subjective measure of exercise intensity. There was no difference in exercise intensity based on percentage of maximal oxygen consumption during hot versus thermo-neutral yoga (30.9% ± 2.3% vs. 30.5% ± 1.8%, p = 0.68). However, exercise intensity was significantly higher during hot versus thermo-neutral yoga based on %HRmax (67.0% ± 2.3% vs. 60.8% ± 1.9%, p = 0.01) and RPE (12 ± 1 vs. 11 ± 1, p = 0.04). According to established exercise intensities, hot yoga was classified as light-intensity exercise based on percentage of maximal oxygen consumption but moderate-intensity exercise based on %HRmax and RPE while thermo-neutral yoga was classified as light-intensity exercise based on percentage of maximal oxygen uptake, %HRmax, and RPE. Despite the added hemodynamic stress and perception that yoga is more strenuous in a hot environment, we observed similar oxygen consumption during hot versus thermo-neutral yoga, classifying both exercise modalities as light-intensity exercise. [ABSTRACT FROM AUTHOR]

Résumé Les besoins énergétiques et protéiques du patient obèse restent difficiles à évaluer. En effet, la modification de la composition corporelle liée à l’obésité avec une augmentation de la masse grasse rend peu précise l’utilisation du poids réel dans l’évaluation de ces besoins. La masse maigre déterminant principal de la dépense énergétique de repos et des besoins azotés doit être prise en compte. La calorimétrie indirecte est la méthode de référence pour l’évaluation de la dépense énergétique du sujet obèse, elle est néanmoins difficile d’accès. De ce fait, certaines formules prédictives de la dépense énergétique de repos peuvent donc être utilisées. Les formules d’Harris et Benedict, de Mifflin et al., de Müller et al. semblent plus précises chez le sujet obèse, de même que l’équation de Huang et al. prenant en compte la masse maigre. En cas d’agression, leurs prédictions sont moins fiables. Dans ce contexte, la formule d’Harris et Benedict peut être utilisée en utilisant le poids ajusté et un facteur correctif de 1,3. En cas de ventilation mécanique, la formule de Penn State modifiée est la plus satisfaisante. Les besoins énergétiques journaliers de l’obèse peuvent être aussi évalués de façon empirique à la hauteur de 20 à 25 kcal/kg de poids ajusté. Les besoins protéiques sont plus complexes à évaluer. En l’absence de recommandation à ce niveau, des apports protéiques quotidiens de 1,0–1,1 g/kg de poids réel en l’absence d’agression et de 2 g/kg de poids idéal en cas d’agression peuvent être conseillés. The energy and protein needs of obese patients remain difficult to assess. Indeed, the change in body composition related to obesity with an increase of fat mass makes the use of real weight not adapted to assess these needs. In addition, the fat-free mass, which is the main determinant of resting energy expenditure and nitrogen needs must be taken into account. Indirect calorimetry is the reference method to assess the energy expenditure of obese subject, but the access remains nevertheless difficult. Therefore, some predictive formulas of resting energy expenditure can be used. The formulas of Harris and Benedict, Mifflin et al., Müller et al. appear to be more accurate in the obese subject, as the equation of Huang et al. using fat-free mass. In critically ill obese patients, their predictions are less reliable. In this context, the Harris and Benedict formula can be used with the adjusted weight and a correction factor of 1.3. In the case of mechanical ventilation, the modified Penn State formula is the most accurate. The daily energy needs of the obese can also be assessed empirically at 20–25 kcal/kg of adjusted weight. Protein needs are more complex to evaluate. In the absence of recommendation at this level, daily protein intakes of 1.0–1.1 g/kg of real weight or 2 g/kg of ideal weight in the absence or presence of injury, respectively, may be recommended. [ABSTRACT FROM AUTHOR]

Frequent breaks in prolonged sitting are associated beneficially with glycaemic control. However, the contribution of energy expenditure to this relationship has not been well characterised. In this exploratory analysis, data from 3 laboratory trials that standardised test meals, cohort characteristics (overweight/obese, sedentary), and break frequency and duration were pooled. Higher energy expenditures of different types of breaks (standing, light- or moderate-intensity walking) were associated with lower postprandial glucose and insulin responses in a dose-dependent manner. [ABSTRACT FROM AUTHOR]

Circuit resistance training (CT) constitutes a high-intensity interval program commonly used to target weight loss; however, the loads and exercise patterns that maximize energy expenditure (EE) remain undetermined. We examined differences in EE among CT protocols using varying loads and contraction speeds in recreationally trained males and females. Seven males (age, 21.1 ± 0.5 years) and 8 females (age, 20.0 ± 0.9 years) performed 3 randomized CT protocols incorporating 3 circuits using heavy-load (80% 1-repetition maximum (1RM)) explosive (HLEC), heavy-load, controlled (2 s) (HLCC), and moderate-load (50% 1RM) explosive contractions (MLEC). Expired air was collected continuously before, during, and after exercise. Blood lactate was collected at rest, immediately postexercise, and 5 min postexercise. No significant differences were detected for resting EE; however, there was a significant difference among conditions during exercise ( p = 0.034, ηp2 = 0.229). Post hoc analysis revealed that MLEC produced significantly higher EE than HLCC, but not HLEC ( p = 0.023). There was a significant difference among conditions for rate of EE during exercise ( p = 0.003, ηp2 = 0.361). Post hoc analysis revealed that HLEC produced a significantly higher EE rate than HLCC ( p = 0.012) or MLEC ( p = 0.001). A condition × sex interaction was seen for blood lactate changes (ηp2 = 0.249; p = 0.024). Females produced significantly greater change for MLEC than HLEC ( p = 0.011), while males showed no significant differences. Our results favor CT using MLEC for a higher EE during a full workout; however, the rate of EE was highest when using HLEC. [ABSTRACT FROM AUTHOR]

Adaptations to sprint interval training (SIT) are observed with brief (≤15-s) work bouts highlighting peak power generation as an important metabolic stimulus. This study examined the effects of manipulating SIT work bout and recovery period duration on energy expenditure (EE) during and postexercise, as well as postexercise fat oxidation rates. Nine active males completed a resting control session (CTRL) and 3 SIT sessions in randomized order: ( i) 30:240 (4 × 30-s bouts, 240-s recovery); ( ii) 15:120 (8 × 15-s bouts, 120-s recovery); (3) 5:40 (24 × 5-s bouts, 40-s recovery). Protocols were matched for the total duration of work (2 min) and recovery (16 min), as well as the work-to-recovery ratio (1:8 s). EE and fat oxidation rates were derived from gas exchange measured before, during, and for 3 h postexercise. All protocols increased EE versus CTRL ( P < 0.001). Exercise EE was greater ( P < 0.001) with 5:40 (209 kcal) versus both 15:120 (163 kcal) and 30:240 (138 kcal), while 15:120 was also greater ( P < 0.001) than 30:240. Postexercise EE was greater ( P = 0.014) with 15:120 (313 kcal) versus 5:40 (294 kcal), though both were similar ( P > 0.077) to 30:240 (309 kcal). Postexercise fat oxidation was similar ( P = 0.650) after 15:120 (0.104 g·min−1) and 30:240 (0.116 g·min−1) and both were greater ( P < 0.030) than 5:40 (0.072 g·min−1) and CTRL (0.049 g·min−1). In conclusion, shorter SIT work bouts that target peak power generation increase exercise EE without compromising postexercise EE, though longer bouts promote greater postexercise fat utilization. [ABSTRACT FROM AUTHOR]

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Pounding food items in a wooden mortal is a common home chore in many communities in African and Asian countries. However, no empirical data exist on energy expenditure during this activity, and whether the activity can be considered a light, moderate, or vigorous intensity physical activity is unknown. Purpose: This study was aimed at gaining insights into energy expenditure during millet pounding through cardiovascular responses to millet pounding activity, and to explore possible differences in response between women who pound millet as their occupation (habitual millet pounders) and those who pound millet only for their own home cooking but not as a job (nonhabitual pounders). Methods: A total of forty apparently healthy women performed millet pounding activity in standing position for 15 min durations, and their cardiovascular parameters including heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressures (DBPs), and rated perceived exertion (RPE) at rest, and immediately after pounding activity were assessed. Results: Significant increases in the subjects' cardiovascular parameters in the range of 7-12, 1-5, and 19-21 point values above the resting levels for SBP, DBP, and HR, respectively, were observed. Significantly higher SBP was also observed for the habitual pounders than the values for the nonhabitual pounders, whereas RPE was significantly higher for the nonhabitual pounders than for the habitual pounders in response to pounding. Conclusion: This study suggests that millet pounding substantially stresses the cardiovascular system sufficiently to place the activity within the moderate intensity category. Further studies on energy cost of this house chore, using instrumentation that is capable of direct measure of oxygen consumption, is warranted. [ABSTRACT FROM AUTHOR]

This study investigated substrate oxidation in concentric and eccentric cycling matched for aerobic power output in the postprandial state. Energy expenditure, respiratory exchange ratio, and fat and carbohydrate oxidation rates were measured at rest and after 15, 30, and 45 min of eccentric and concentric cycling in 12 men. Absolute and relative aerobic power output and energy expenditure were similar during concentric and eccentric exercise. No effect of exercise modality was observed for substrate metabolism. [ABSTRACT FROM AUTHOR]

Résumé Notre rythme de vie actuel a entraîné une diminution progressive du temps alloué au sommeil. En France, une personne sur 3 dormirait moins de 7 heures par nuit. Dans le même temps, le nombre de patients souffrant d’obésité a augmenté. De nombreuses études épidémiologiques soulignent le lien entre la faible durée du temps de sommeil et la prise de poids. En parallèle, les études expérimentales ont observé que la privation de sommeil modifiait le comportement alimentaire en augmentant la sensation de faim et la prise alimentaire. Le cycle nycthéméral induit par l’alternance lumière–obscurité a une influence majeure sur le sommeil mais aussi sur le comportement alimentaire : la lumière agit sur les noyaux suprachiasmatiques, puis secondairement sur les noyaux préoptiques et les noyaux latéraux de l’hypothalamus d’où l’augmentation des orexines. Plusieurs théories tentent d’expliquer l’augmentation de la prise alimentaire : la première, phylogénétique, serait liée aux variations de la durée du sommeil au cours des saisons ; la deuxième concernerait l’adaptation anticipatoire face à l’éveil ; la dernière serait liée à une modification du contrôle hédonique de la prise alimentaire. De nombreuses pathologies altèrent la relation physiologique sommeil–comportement alimentaire, comme par exemple le syndrome d’apnée du sommeil. Il est donc nécessaire de mieux comprendre cette relation pour améliorer la prise en charge des personnes obèses et pour prévenir le développement du surpoids par le respect d’un rythme du sommeil adapté à l’enfant. Our current lifestyle leads to a gradual reduction in the time allocated to sleep. In France, one in three people is sleeping less than 7 hours a night. In parallel, the number of patients suffering from obesity increases. Numerous epidemiological studies emphasize the link between short sleep duration and weight gain. They highlight a number of factors that can influence this relationship including age, female gender or genetic factors. Experimental studies have also found that sleep deprivation altered feeding behaviour by increasing the feeling of hunger, food intake and plasma levels of ghrelin. The circadian cycle due to the alternation of light/darkness has a major influence on sleep but also on eating behaviour. Light acts on suprachiasmatic nuclei and then on preoptical as well as on lateral nuclei of the hypothalamus by increasing the secretion of orexins. Several theories have been advanced in order to explain the increase in food intake: the first, phylogenetic, would be linked to changes in sleep duration over the seasons; the second concerns anticipatory adaptation face to the awakening; the last to be related to the hedonic regulation of food intake. Many pathologies act by changing the sleep–eating behaviour relationship. Therefore, it is necessary to better understanding this relationship to prevent nutritional consequences by an optimal dietary management and by learning healthy lifestyle in children. [ABSTRACT FROM AUTHOR]

Background Ventricular ectopic beats (VEBs) are considered as benign ventricular arrhythmias in patients without structural heart disease. However, symptomatic frequent VEBs can adversely affect energy metabolism. The present study aimed to determine the effect of symptomatic frequent VEBs on energy expenditure, physical activity and sleep pattern. Methods Thirty-seven patients with symptomatic frequent VEBs and no structural heart diseases were enrolled. Patients underwent simultaneous 24-hour-ambulatory Holter electrocardiogram monitoring and the BodyMedia armband device monitoring which measures energy expenditure. Data acquired from both devices were compared with the data acquired from healthy volunteers in the control group. Results Total energy expenditure (TEE) was higher in the patient group than the control group (1470 ± 353 kcal vs 1125 ± 275 kcal, P < 0.001). Average metabolic equivalence (aMETs) (1.1 ± 0.2 vs. 1.3 ± 0.2, P = 0.028), physical activity duration (PAD) (0.35 vs. 0.48, P = 0.007) and sleep duration (SDN) (3.15 vs. 4.31, P = 0.004) were significantly lower in the patient group than control group. VEBs frequency was inversely correlated with only SDN ( r = −0.374, P = 0.027). Conclusion Total energy expenditure (TEE) is increased in patients with symptomatic frequent VEBs in comparison with healthy subjects while PAD, average metabolic equivalence (aMETs) and SDN are decreased. VEBs frequency was inversely correlated with SDN. [ABSTRACT FROM AUTHOR]

The current experiment tested the hypothesis that consumption of a high-fat diet (HFD) would differentially affect metabolic parameters in obesity-prone Osborne-Mendel (OM) and obesity-resistant S5B/Pl (S5B) rats. In OM rats consuming a HFD, an increase in HFD intake, body mass, and percent fat mass, and a HFD-induced decrease in metabolic rate and energy expenditure were demonstrated. In S5B rats consuming a HFD, no change in percent body fat or HFD intake was demonstrated and HFD increased metabolic rate and energy expenditure. To assess whether HFD differentially altered skeletal muscle markers of metabolism inOMand S5B rats, the expression of the transporters, CD36 and GLUT4, and the energy sensors, AMPK and PPARγ, in the gastrocnemius muscle was measured. Oxidation and lipid accumulation in the gastrocnemius muscle was histologically determined. Consumption of a HFD decreased phosphorylated AMPK and PPARγ expression in the skeletal muscle of obesity-prone OM rats. Lipid accumulation in skeletal muscle was significantly higher in OM rats fed a HFD. Overall, these data suggest that the differential response to HFD on metabolic rate, energy expenditure, and phosphorylated AMPK and PPARγ in OM and S5B rats, may partially account for differences in the susceptibility to develop obesity. [ABSTRACT FROM AUTHOR]

Résumé Alors que la pratique régulière d’une activité physique (AP) est recommandée en cas d’hypertension artérielle (HTA), le niveau d’AP des sujets hypertendus reste mal connu. Notre objectif était d’étudier l’association entre le niveau d’AP et le caractère contrôlé ou non de l’HTA de sujets vus en consultation dans 9 centres spécialisés en HTA. Quatre-vingt-cinq sujets hypertendus ont été inclus (59 ± 14 ans, 61 % d’hommes, 12 % fumeurs, 29 % diabétiques). Au décours de leur consultation, une automesure tensionnelle (AMT) sur 7 jours (2 mesures le matin + 2 le soir) était réalisée, ainsi qu’un compte rendu de leurs activités quotidiennes permettant d’estimer la dépense calorique additionnelle à l’aide d’une réglette Acti-MET extrapolée du questionnaire international d’activités physiques (IPAQ). Les sujets complétaient ensuite un auto-questionnaire « score de Dijon » sur 30 points (distinguant les sujets actifs, score > 20/30, des sédentaires < 10/30). Les hypertendus contrôlés en AMT (< 135/85 mm Hg) (55 % des sujets), en comparaison aux non contrôlés, étaient plus âgés, avaient une tendance non significative à une dépense calorique déclarée plus élevée (4959 ± 5045 kcal/semaine vs 4048 ± 4199 kcal/semaine, p = 0,3755) et leur score de Dijon (19,44 ± 5,81 vs 18,00 ± 4,32, p = 0,2094) montrait une proportion de sujets « actifs » plus importante (48,9 % vs 34,2 %, p = 0,1773). En conclusion, nos résultats ont objectivé une « tendance » à une AP déclarée plus importante pour les sujets dont l’HTA est contrôlée. Ceci nous encourage à poursuivre par une étude qui inclurait davantage de sujets et dont l’AP serait évaluée par le port pendant 7 jours d’un capteur de type accéléromètre (méthode objective). While physical activity (PA) is recommended for high blood pressure management, the level of PA practice of hypertensive patients remains unclear. We aimed to assess the association between the level of both PA and blood pressure of individuals consulting in 9 hypertension specialist centres. Eighty-five hypertensive patients were included (59 ± 14 years, 61% men, 12% smokers, 29% with diabetes). Following their consultation, they performed home blood pressure measurement (HBPM) over 7 days (2 in the morning + 2 in the evening), they wrote in a dedicated form their daily activities to estimate the additional caloric expenditure using Acti-MET device (built from International physical Activity Questionnaire [IPAQ]). Thus, patients completed a self-administered questionnaire “score of Dijon” (distinguishing active subjects with a score > 20/30, from sedentary < 10/30). Subjects with normal HBPM value (< 135/85 mm Hg) (55% of them) compared to those with high HBPM were older, had a non-significant trend towards higher weekly caloric expenditure (4959 ± 5045 kcal/week vs. 4048 ± 4199 kcal/week, P = 0.3755) and score of Dijon (19.44 ± 5.81 vs. 18.00 ± 4.32, P = 0.2094) with a higher proportion of “active” subjects (48.9% vs. 34.2%, P = 0.1773). In conclusion, our results demonstrate a “tendency” to a higher level of reported PA for subjects whose hypertension was controlled. This encourages us to continue with a study that would include more subjects, which would assess PA level using an objective method such as wearing an accelerometer sensor. [ABSTRACT FROM AUTHOR]

Many studies have researched the psychophysiological response and energy balance of athletes in numerous ultraendurance probes, but none has investigated an ultraendurance mountain running event. The current study aims to analyze changes in blood lactate concentration, rating of perceived exertion, heart rate, heart rate variability, and energy balance after the performance of an ultraendurance mountain running event. The parameters in the 6 participants who finished the event were analyzed (age, 30.8 ± 3.1 years; height, 176.2 ± 8.6 cm; body mass, 69.2 ± 3.7 kg). The race covered 54 km, with 6441 m of altitude change, 3556 m downhill and 2885 m uphill. The athletes completed together the race in 14 h and 6 min. After the ultraendurance event, the athletes presented a negative energy balance of 4732 kcal, a blood lactate concentration of 2.8 ± 0.3 mmol/L, a heart rate mean/heart rate maximum ratio of 0.64, a heart rate mean of 111.4 ± 5.9 beats/min, a decrease in vagal modulation, and an increase in sympathetic modulation, and recorded 19.5 ± 1.5 points on the 6-20 rating of perceived exertion scale. The event was a stressful stimulus for the athletes despite the low intensity measured by blood lactate concentration and heart rate. The results obtained may be used by coaches as a reference parameter of heart rate, heart rate variability, rating of perceived exertion, and lactate concentration to develop specific training programs. In addition, the energy balance data obtained in this research may improve nutritional intake strategies. [ABSTRACT FROM AUTHOR]

Nutrition support has been shown to have a positive impact on critically ill patients who meet their defined goals of nutrition therapy. However, inappropriate energy assessment can contribute to under- or overfeeding resulting in deleterious effects. Thus, assessment of energy expenditure in critically ill patients is crucial to prevent negative impacts from inappropriate feeding. Currently, the optimal energy requirement and appropriate energy assessment in these patients is controversial. Indirect calorimetry or predictive equations have been suggested to evaluate energy expenditure in critically ill patients. Indirect calorimetry is a gold standard for evaluating energy expenditure, but it is not always available and has some limitations. Many predictive equations, therefore, have been developed to predict energy expenditure in critically ill patients. However, these equations cannot be used generally in these patients since they were developed in a unique patient population. Many studies compared measured energy expenditure with predictive energy expenditure, but the data regarding accuracy is not robust. Therefore, clinicians should consider using these equations carefully based on the current supporting data. Indirect calorimetry is recommended for use in evaluating energy expenditure in critically ill patients if it is available. [ABSTRACT FROM AUTHOR]

Most sprint interval training (SIT) research involves cycling as the mode of exercise and whether running SIT elicits a similar excess postexercise oxygen consumption (EPOC) response to cycling SIT is unknown. As running is a more whole-body-natured exercise, the potential EPOC response could be greater when using a running session compared with a cycling session. The purpose of the current study was to determine the acute effects of a running versus cycling SIT session on EPOC and whether potential sex differences exist. Sixteen healthy recreationally active individuals (8 males and 8 females) had their gas exchange measured over ∼2.5 h under 3 experimental sessions: ( i) a cycle SIT session, ( ii) a run SIT session, and ( iii) a control (CTRL; no exercise) session. Diet was controlled. During exercise, both SIT modes increased oxygen consumption (cycle: male, 1.967 ± 0.343; female, 1.739 ± 0.296 L·min−1; run: male, 2.169 ± 0.369; female, 1.791 ± 0.481 L·min−1) versus CTRL (male, 0.425 ± 0.065 L·min−1; female, 0.357 ± 0.067; P < 0.001), but not compared with each other ( P = 0.234). In the first hour postexercise, oxygen consumption was still increased following both run (male, 0.590 ± 0.065; female, 0.449 ± 0.084) and cycle SIT (male, 0.556 ± 0.069; female, 0.481 ± 0.110 L·min−1) versus CTRL and oxygen consumption was maintained through the second hour postexercise (CTRL: male, 0.410 ± 0.048; female, 0.332 ± 0.062; cycle: male, 0.430 ± 0.047; female, 0.395 ± 0.087; run: male, 0.463 ± 0.051; female, 0.374 ± 0.087 L·min−1). The total EPOC was not significantly different between modes of exercise or males and females ( P > 0.05). Our data demonstrate that the mode of exercise during SIT (cycling or running) is not important to O2 consumption and that males and females respond similarly. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that, like adding exercise, reducing sitting time may improve cardiometabolic health. There has not been a direct comparison of the 2 strategies with energy expenditure held constant. The purpose of this study was to compare fasting and postmeal glucose and insulin concentrations in response to a day with frequent breaks from sitting but no exercise versus considerable sitting plus moderate exercise. Ten sedentary overweight/obese office workers were tested in 3 conditions: ( i) walking per activity guidelines (AGW): sitting for majority of workday with a 30 min pre-lunch walk; ( ii) frequent long breaks (FLB): no structured exercise but frequent breaks from sitting during workday with energy expenditure matched to AGW; and ( iii) frequent short breaks (FSB): number of breaks matched to FLB, but duration of breaks were shorter. Plasma glucose and insulin areas under the curve were measured in response to a meal tolerance test (MTT) at the end of the workday and interstitial glucose was evaluated throughout the day and overnight using continuous glucose monitoring. Using repeated-measures linear mixed models, area under the curve of plasma glucose or insulin after the MTT was not different between conditions. Glycemic variability was lower in FLB compared with AGW ( p < 0.05), and nocturnal duration of elevated glucose (>7.8 mmol/L) was shorter after FLB (2.5 ± 2.5 min) than AGW (32.7 ± 16.4 min) or FSB (45.6 ± 29.6 min, p = 0.05). When energy expenditure was matched, breaks from sitting approximated the effects of moderate-intensity exercise on postmeal glucose and insulin responses and more effectively constrained glycemic variability. [ABSTRACT FROM AUTHOR]

Subjects performed high-intensity interval training (HIIT) and continuous moderate-intensity training (END) to evaluate 24-h oxygen consumption. Oxygen consumption during HIIT was lower versus END; however, total oxygen consumption over 24 h was similar. These data demonstrate that HIIT and END induce similar 24-h energy expenditure, which may explain the comparable changes in body composition reported despite lower total training volume and time commitment. [ABSTRACT FROM AUTHOR]

Physical inactivity is highly common in adults with type 1 diabetes (T1D) as specific barriers (i.e., hypoglycemia) may prevent them from being active. The objective of this study was to examine the efficacy of the Physical Exercise Promotion program in type 1 diabetes (PEP-1) program, a group program of physical activity (PA) promotion (intervention) compared with an information leaflet (control), to improve total energy expenditure (TEE) in adults with T1D after 12 weeks. TEE was measured with a motion sensor over a 7-day period at inclusion, after the program (12 weeks) and 1-year after inclusion. The 12 weekly sessions of the program included a 30-min information session (glycemic control and PA) and 60 min of PA. A total of 48 adults, aged 18 to 65 years with a reported PA practice <150 min per week, were recruited (45.8% men; aged 44.6 ± 13.3 years; 8.0% ± 1.1% glycated hemoglobin (A1c)) and randomized in this pilot trial. Ninety percent of participants completed the program and 88% completed the 1-year follow-up. No change was observed for TEE and A1c in both groups. After the 12-week program, the mean peak oxygen uptake increased (14%; p = 0.003) in the intervention group; however, at the 1-year follow-up, it was no longer different from baseline. In the control group, no difference was observed for the peak oxygen uptake. These results suggest that the PEP-1 pilot program could increase cardiorespiratory fitness. However, this benefit is not sustained over a long-term period. The PEP-1 program did not increase TEE in patients with T1D and other strategies remain necessary to counteract physical inactivity in this population. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Animal Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Les Cahiers de l'Année Gérontologique is the property of Lavoisier and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Postmenopausal women experience an age-related decline in resting energy expenditure (REE), which is a risk factor for energy imbalance and metabolic disease. Exercise, because of its association with greater lean tissue mass and other factors, has the potential to mediate REE decline, but the relation between exercise and REE in postmenopausal women is not well characterized. This study tests the hypothesis that exercise energy expenditure (EEE) is positively associated with REE and can counter the effects of age and menopause. It involves a cross-sectional sample of 31 healthy postmenopausal women (aged 49-72 years) with habitual exercise volumes at or above levels consistent with current clinical recommendations. Subjects kept exercise diaries for 4 weeks that quantified exercise activity and were measured for body composition, maximal oxygen uptake, and REE. Multiple regression analysis was used to test for associations between EEE, age, body composition, and REE. There was a significant positive relation between EEE and lean tissue mass (fat-free mass and fat-free mass index). The relation between REE and EEE remained significant even after controlling for lean tissue mass. These results support the hypothesis that exercise is positively associated with REE and can counter the negative effects of age and menopause. They also indicate a continuous relation between exercise and REE across ranges of exercise, from moderate to high. Exercise at levels that are at or above current clinical guidelines might, in part, ameliorate the risk for energy imbalance and metabolic disease because of its positive relation with REE. [ABSTRACT FROM AUTHOR]

Résume: Cette revue fait la synthèse de différentes études ayant analysé l’effet de l’activité physique, d’une part sur la composition corporelle, d’autre part sur l’apport énergétique ad libitum, et ainsi éclaire la corrélation entre activité physique et bilan énergétique. Une baisse du degré d’activité physique n’entraîne pas une réduction compensatoire de l’apport énergétique, ce qui se traduit par un bilan énergétique positif et la formation de réserves de graisse. À l’inverse, une activité physique intense régulière provoque une augmentation de l’apport énergétique chez les sujets très entraînés et les individus de corpulence mince. Les sujets obèses non entraînés ne modifient généralement pas leur apport énergétique lorsqu’ils sont soumis à un entraînement. Une activité physique intense régulière est une stratégie efficace pour réduire l’obésité. Nous proposons de discuter, ci-après, les recommandations en matière d’activité physique pour une perte de poids significative au plan clinique [ABSTRACT FROM AUTHOR]

Previous intervention studies suggest that leptin, insulin, insulin-like growth factor 1 (IGF-1), and triiodthyronine (T3) are sensitive markers of inadequate energy intake in relation to exercise expenditures. Because of limitations in metabolic hormone measurements, self-reported energy availability (EA) based on food and activity records may present an alternative for characterizing energy status in young athletes. The purpose of the current study was to assess whether self-reported EA is related to leptin, insulin, IGF-1, and T3 in 352 young athletes. Sex, body composition, sport participation, and acute weight changes were considered as confounding variables. Multiple linear regression revealed that EA was negatively associated with leptin ( p < 0.05) but not with insulin, IGF-1, or T3. Female athletes with low EA (<30 kcal·kg−1 fat-free mass (FFM)) had higher leptin concentrations (5.0 ± 4.7 ng·mL−1) and more body fat (18.3% ± 5.1%) than did females with normal EA (leptin, 3.1 ± 2.4 ng·mL−1; body fat, 15.8% ± 4.2%; both, p < 0.001). Athletes reporting acute weight loss (>1 kg·week−1) had a lower EA (18.9 ± 7.4 kcal·kg−1 FFM) than did weight-stable athletes (30.0 ± 11.2 kcal·kg−1 FFM) or athletes reporting weight gain (>1 kg; 49.7 ± 13.1 kcal·kg−1 FFM). IGF-1 and T3 were also reduced in athletes who lost weight ( p < 0.01). This cross-sectional study reveals a lack of association between self-reported EA and metabolic hormones indicative of energy status in young athletes. Further studies are needed to investigate whether self-reported EA and metabolic hormones are in better agreement when measured repeatedly. [ABSTRACT FROM AUTHOR]

Professional jockeys are unique amongst weight-making athletes in that they are required to make weight on a daily basis by often using potentially hazardous methods, such as food deprivation, dehydration, and forced vomiting. To allow the prescription of accurate energy intake (EI), it is essential to understand the energy requirements of jockeys; however, these data are currently not known. Therefore, we measured the energy expenditure (EE) of professional jockeys during a simulated race ride and for a working day (nonracing) that involved typical stable duties. The accuracy of 2 portable lightweight devices, the Polar RS400 commercial heart rate monitor (CHRM) and the Actiheart monitor (AH) were initially assessed during 30 min of exercise compared with respiratory gas analysis (GA) ( n = 9). No significant difference was observed ( p > 0.05) and 95% limits of agreement analysis (LoA) showed that CHRM was more closely related to GA (bias: -0.015; LoA: -0.049, +0.019 MJ) than AH (bias: -0.007; LoA: -0.073, +0.059 MJ). A laboratory-based 2-mile (3.2-km) racing protocol was created and EE was assessed using CHRM, GA, and AH. We report that a typical race expends 0.18 (SD ±0.03) MJ. Finally, in a separate group of jockeys ( n = 8), 24-h EE was assessed using CHRM. The mean (±SD) EE for a typical day was 11.26 (±1.49) MJ. Additionally, we measured EI using 7-day self-reporting food record diaries. Mean EI was 7.24 (±0.92) MJ, largely consumed as 2 main meals. These data provide a platform to implement dietary strategies that create appropriate weight-loss targets and therefore improve the physical and mental well-being of professional jockeys. [ABSTRACT FROM AUTHOR]

Small Unit Tactics (SUT) is a 64-day phase of the Special Forces Qualification Course designed to simulate real-world combat operations. Assessing the metabolic and physiological responses of such intense training allows greater insights into nutritional requirements of soldiers during combat. The purpose of this study was to examine energy balance around specific training events, as well as changes in body mass and composition. Data were collected from 4 groups of soldiers ( n = 36) across 10-day periods. Participants were 28 ± 5 years old, 177 ± 6 cm tall, and weighed 83 ± 7 kg. Doubly labeled water (D218O) was used to assess energy expenditure. Energy intake was calculated by subtracting energy in uneaten foods from known energy in distributed foods in individually packaged combat rations or in the dining facility. Body composition was estimated from skinfold thickness measurements on days 0 and 64 of the course. Simulated urban combat elicited that largest energy deficit (11.3 ± 2.3 MJ·day−1 (2700 ± 550 kcal·day−1); p < 0.05), and reduction in body mass (3.3 ± 1.9 kg; p < 0.05), during SUT, while energy balance was maintained during weapons familiarization training and platoon size raids. Over the entire course body mass decreased by 4.2 ± 3.7 kg ( p < 0.01), with fat mass decreasing by 2.8 ± 2.0 kg ( p < 0.01) and fat-free mass decreasing by 1.4 ± 2.8 kg ( p < 0.05). The overall reduction in body mass suggests that soldiers were in a negative energy balance during SUT, with high energy deficit being observed during strenuous field training. [ABSTRACT FROM AUTHOR]

This technical note describes methods to improve activity energy expenditure estimates by using a multi-sensor board (MSB) to measure slope. Ten adults walked over a 4-km (2.5-mile) course wearing an MSB and mobile calorimeter. Energy expenditure was estimated using accelerometry alone (base) and 4 methods to measure slope. The barometer and global positioning system methods improved accuracy by 11% from the base ( p < 0.05) to 86% overall. Measuring slope using the MSB improves energy expenditure estimates during field-based activities. [ABSTRACT FROM AUTHOR]

Complete leptin deficiency is associated with weight gain and extreme obesity, according to studies of animals and of monogenic obesity in humans. It is still a matter of debate whether relative leptin deficiency plays a physiologic role in adiposity regulation in free-living humans. We hypothesized that leptin levels would be associated with subsequent weight changes in healthy normal-weight young adults. Our prospective cohort involved 150 healthy young adults (114 women and 36 men) followed over their years of study at the Université de Sherbrooke. Anthropometric measurements, fasting blood samples, 3-day food diaries, and a physical activity questionnaire were collected at baseline. Leptin levels were measured with radioimmunoassay. Associations between baseline leptin levels and subsequent anthropometric changes were assessed with multivariable linear regression models to account for adiposity at baseline, food intake, and energy expenditure. Over the 2-year follow-up, changes in body mass index (BMI) ranged from -0.8 to +2.6 kg·m-2 in men (mean BMI change, +0.6 kg·m-2) and from -2.5 to +3.7 kg·m-2 in women (mean BMI change, +0.1 kg·m-2). Lower leptin levels at baseline were associated with a higher risk of weight gain in women ( r = -0.24; p = 0.01 for change in BMI) and in men ( r = -0.27, p = 0.11), even after accounting for baseline BMI, total daily caloric intake, and energy expenditure ( p = 0.02). In the subsample measured at 4 years ( n = 63), baseline leptin levels were not associated with 4-year weight changes. Lower leptin levels are associated with a higher risk of weight gain over 2 years in healthy young adults. [ABSTRACT FROM AUTHOR]

Research on the effect of caffeine on energy expenditure (EE), physical activity (PA), and total sleep time (TST) during free-living conditions using objective measures is scarce. We aimed to determine the impact of a moderate dose of caffeine on TST, resting EE (REE), physical activity EE (PAEE), total EE (TEE), and daily time spent in sedentary, light, moderate, and vigorous intensity activities in a 4-day period and the acute effects on heart rate (HR) and EE in physically active males. Using a double-blind crossover trial (ClinicalTrials.gov ID: NCT01477294) with two conditions (4 days each with 3-day washout) randomly ordered as caffeine (5 mg/kg of body mass/day) and placebo (maltodextrin) administered twice per day (2.5 mg/kg), 30 nonsmoker males, low-caffeine users (<100 mg/day), aged 20–39, were followed. Body composition was assessed by dual-energy X-ray absorptiometry. PA was assessed by accelerometry, while a combined HR and movement sensor estimated EE and HR on the second hour after the first administration dose. REE was assessed by indirect calorimetry, and PAEE was calculated as [TEE − (REE + 0.1TEE)]. TST and daily food records were obtained. Repeated measures ANOVA and ANCOVA were used. After a 4-day period, adjusting for fat-free mass, PAEE, and REE, TST was reduced (p = 0.022) under caffeine intake, while no differences were found between conditions for REE, PAEE, TEE, and PA patterns. Also, no acute effects on HR and EE were found between conditions. Though a large individual variability was observed, our findings revealed no acute or long-term effects of caffeine on EE and PA but decreased TST during free-living conditions in healthy males. [ABSTRACT FROM AUTHOR]

It has previously been shown that low-frequency neuromuscular electrical stimulation (NMES) techniques can induce increases in energy expenditure similar to those associated with exercise. This study investigated the metabolic and cardiovascular effects of a 1 h session of lower limb NMES and compared cardiovascular response with that observed during walking in nine obese subjects (three males) (age = 43.8 ± 3.0 years; body mass index (BMI) = 41.5 ± 1.8 kg/m2). The NMES protocol consisted of delivering a complex pulse pattern to the thigh muscles for 1 h. The walking test consisted of five 4-min bouts starting at 2 km/h with 1 km/h increments up to 6 km/h. In both tests, an open-circuit gas analyser was used to assess O2 consumption (VO2), CO2 production (VCO2), respiratory exchange ratio (RER), and heart rate (HR). Rates of fat oxidation (RFO) and carbohydrate oxidation (CHO) were estimated by indirect calorimetry. One hour of NMES significantly increased VO2, HR, RER, and mean energy expenditure compared with resting values, reaching 8.7 ± 1.3 mL⋅min-2⋅kg-1 (47% of VO2peak), 114.8 ± 7.5 bpm, 0.95, and 318.5 ± 64.3 kcal/h, respectively. CHO, but not RFO, increased during 1 h of NMES. With NMES, CHO was greater and RFO was less than at all walking speeds except 6 km/h. Lactate also increased more with NMES, to 3.5 ± 0.7 mmol versus a maximum of 1.5 ± 0.3 mmol with the walking protocol. These results suggest that NMES can be used in an obese population to induce an effective cardiovascular exercise response. In fact, the observed increase in energy expenditure induced by 1 h of NMES is clinically important and comparable with that recommended in weight management programs. [ABSTRACT FROM AUTHOR]

Exenatide is a medication similar in structure and effect to native glucagon-like peptide-1, an incretin hormone with glucose-lowering properties. The aim of the study was to measure the change in total energy expenditure (TEE) and body composition during exenatide administration and by deduction the relative contributions of energy expenditure and energy intake to exenatide-induced weight loss. Forty-five obese (body mass index, 30-40 kg·m-2) subjects were identified. After exclusion criteria application, 28 subjects entered into the study and 18 subjects (12 female, 6 male) completed the study, which consisted of 6 visits over 14 weeks and injection of exenatide for an average of 84 ± 5 days. Respiratory gas analysis and doubly labeled water measurements were performed before initiation of exenatide and after approximately 3 months of exenatide administration. The average weight loss from the beginning of injection period to the end of the study in completed subjects was 2.0 ± 2.8 kg ( p = 0.01). Fat mass declined by 1.3 ± 1.8 kg ( p = 0.01) while the fat-free mass trended downward but was not significant (0.8 ± 2.2 kg, p = 0.14). There was no change in weight-adjusted TEE ( p = 0.20), resting metabolic rate ( p = 0.51), or physical activity energy expenditure ( p = 0.38) and no change in the unadjusted thermic effect of a meal ( p = 0.37). The significant weight loss because of exenatide administration was thus the result of decreasing energy intake. In obese nondiabetic subjects, exenatide administration did not increase TEE and by deduction the significant weight loss and loss of fat mass was due to decreased energy intake. [ABSTRACT FROM AUTHOR]

Copyright of Reanimation is the property of Lavoisier and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Reanimation is the property of Lavoisier and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: Aim: Values of energy expenditure during a circuit training realized with or without whole-body vibration (WBV) have been compared in women regularly trained with WBV. Methods: Ten women performed firstly, a test of maximal oxygen consumption and first ventilator threshold determination. Then, during two other sessions, they realized in a random order two training programs with or without WBV, composed by sequences of dynamic exercises during a 30-minute period. Energy expenditure was calculated from oxygen consumption values during the whole test. Results and discussion: A significant effect of vibration was observed on energy expenditure values during the training program. Adding vibration leads to an increase in energy expenditure by 15.48% when compared with the same program without vibration. Exercise intensity during the 30-minute exercise was respectively 52.7±3.1% VO2max with vibration vs 43.7±3.3% VO2max without vibration. Conclusion: These results indicate that during a training program composed by sequences of dynamic exercises, vibration leads to a significant increase in energy expenditure. Thus, it suggests that vibration could be considered as an alternative method to elicit a cardiovascular solicitation especially in population not motivated to practice classical locomotion exercises, classically used to maintain aerobic fitness. [ABSTRACT FROM AUTHOR]

Abstract: Traumatic injury and severe brain injuries in particular, have systemic consequences affecting all major functions. As energy expenditure increases, energy needs are covered by gluconeogenesis from muscle protein even if they are modulated by the use of different drugs. A gradual erosion of protein reserves results in an acute state of malnutrition exacerbating the immunosuppression induced by trauma, and facilitates infection. Artificial nutrition may limit this process. Gastric feeding route should be initiated early and guided by a written protocol. Gastroparesis being one of the main causes of failure of this route, it must be quickly identified, before calorie deficit harms patients. Nasojejunal tube or parenteral nutrition must be then considered in order to cover nutritional requirements which correspond to about 20–25kcal/kg per day during the initial phase, and up to 30kcal/kg per day during the recovery period. Sepsis, agitation or autonomic dysfunction syndromes may increase nutritional requirements. Their evaluation can be improved by mathematical formulas or calorimetry in complex situations (obesity…). Despite the intensity of muscle catabolism, protein intake should be approximately 1.5g/kg per day. Furthermore, trauma is associated with depletion of glutamine, some vitamins and trace elements including selenium. Supplementation of glutamine reduces infectious morbidity. It must be given at a sufficient dosage and may be associated with selenium. Finally, an adequate glycemic control is essential to avoid brain damage. [Copyright &y& Elsevier]

We report a novel technique for computing diet-induced thermogenesis using data from 24-h respiration chamber measurements of 76 subjects. Physical activity (PA) was determined using a radar system to assess its duration and an accelerometer to evaluate its intensity. The regression line relating PA and energy expenditure facilitated calculation of the integrated thermogenic response to the total energy ingested (11.4% ± 3.8%), which is consistent with the values classically reported in the literature (10%) at the group level. [ABSTRACT FROM AUTHOR]

Summary: Aim: Estimate through the purely cognitive activity of chess the impact of a mental task on the cardiorespiratory system and the metabolic activity. Methods: Eighteen chess players played a chess match (2×15minutes). We measured continuously the heart rate (FC), the oxygen consumption (VO2), the carbon dioxide released (VCO2), the breath frequency (FR), ventilation (VE) and tidal volume (VT). Indirect calorimetry was used to estimate the substrates oxidation and the energy expenditure. We observed in chess players a significant increase in FC, and FR during the game. These increases are similar to those measured during low energy cost physical activities. In addition, a rapid decrease in the respiratory exchange ratio (QR) was also highlighted during this activity. Conclusion: This cognitive task requiring a high mental effort seems to be a relevant human model to study the physiological-induced changes due to psychological stress. [Copyright &y& Elsevier]

Summary: Purpose: The aim of this study was to analyse perceptive, muscular and physiological modifications induced by an ergonomic saddle that has no perineum support and allowing pelvis mediolateral movement. Method: Eight non cyclists conducted a cycle exercise on an ergometer corresponding to four bouts (3-min each bout) at incremental power output (50 to 200 W) with standard and ergonomic saddles, in randomised order between saddles. Rate of perceived exertion, electromyography activities of six lower limb muscles and mechanical efficiency were continuously measured during each bout. Conclusions: Efficiency at 50 W was significantly reduced with ergonomic saddle versus standard, which could be explained by an increase of the internal work with the ergonomic saddle due to the pelvis movement. In contrast, at the higher workload of 200 W, the gross efficiency was not different between saddles and the rate of perceived exertion was significantly reduced with ergonomic saddle versus standard. Moreover, lower muscular activation (−18 and −23%) was shown at 200 W on vastus lateralis muscle (one of the mean muscular force producers) and tibialis anterior muscle (one of the muscles facilitating top and bottom dead centres). All these results allowed to expect a pedalling efficiency improvement with the ergonomic saddle. [Copyright &y& Elsevier]

Space travelers experience anorexia and body weight loss in a microgravity environment, and microgravity-like situations cause changes in hypothalamic activity. Hypothalamic melanocortins play a critical role in the regulation of metabolism. Therefore, we hypothesized that microgravity affects metabolism through alterations in specific hypothalamic signaling pathways, including melanocortin signaling. To address this hypothesis, the microgravity-like situation was produced by an antiorthostatic tail suspension in wild-type and agouti mice, and the effect of tail suspension on energy expenditure and hypothalamic gene expression was examined. Energy expenditure was measured using indirect calorimetry before and during the tail suspension protocol. Hypothalamic tissues were collected for gene expression analysis at the end of the 3 h tail suspension period. Tail suspension significantly increased oxygen consumption, carbon dioxide production, and heat production in wild-type mice. Tail suspension-induced increases in energy expenditure were not attenuated in agouti mice. Although tail suspension did not alter hypothalamic proopiomelanocortin (POMC) and agouti-related protein (AGRP) mRNA levels, it significantly increased hypothalamic interleukin 6 (Il-6) mRNA levels. These data are consistent with the hypothesis that microgravity increases energy expenditure and suggest that these effects are mediated through hypothalamic signaling pathways that are independent of melanocortins, but possibly used by Il-6. [ABSTRACT FROM AUTHOR]

Abstract: In anorexia nervosa, weight loss and malnutrition are responsible for metabolic, hormonal and behavioural consequences. An important decrease in energy expenditure (EE) is observed during fasting states of the disease, but the refeeding and the weight gain induce on the contrary a marked increase in EE, including an increase in resting EE, in diet-induced thermogenesis and in EE related to physical activity. There is also a dramatic fall in protein catabolism and glucose disposal during the fasting stages of the disease. During renutrition, these profiles are normalized long time before normalisation of body weight. Malnutrition and slimming diet induce some alterations in muscles mass and function, which lead difficult the refeeding, for example by slowing gastric emptying. As showed in rats, the restrictive diet together with the access to physical activity, which is secondary to anorectic thought, are responsible to increase the cognitive restrictive diet and to enhance mental and physical hyperactivity as well. Energy and nutrients deficiencies are the consequence to fear of becoming obese, but could also induce, in one third of the cases, binge-eating and thus purging. Recent studies have provided no evidence that anorexia nervosa is caused by neural, hormonal or metabolic factors and/or damages. But these metabolic and cognitive changes, which are mainly the consequence of the starvation, could explain some symptoms or behaviour observed in anorexia nervosa, i.e. those related to the compulsive needs to remain thin and to the fear to being fat. [Copyright &y& Elsevier]