Activity-induced Energy Expenditure Research Articles

Interactions between Lateral Hypothalamic Orexin and Dorsal Raphe Circuitry in Energy Balance.

Orexin/hypocretin terminals innervate the dorsal raphe nucleus (DRN), which projects to motor control areas important for spontaneous physical activity (SPA) and energy expenditure (EE). Orexin receptors are expressed in the DRN, and obesity-resistant (OR) rats show higher expression of these receptors in the DRN and elevated SPA/EE. We hypothesized that orexin-A in the DRN enhances SPA/EE and that DRN-GABA modulates the effect of orexin-A on SPA/EE. We manipulated orexin tone in the DRN either through direct injection of orexin-A or through the chemogenetic activation of lateral-hypothalamic (LH) orexin neurons. In the orexin neuron activation experiment, fifteen minutes prior to the chemogenetic activation of orexin neurons, the mice received either the GABA-agonist muscimol or antagonist bicuculline injected into the DRN, and SPA/EE was monitored for 24 h. In a separate experiment, orexin-A was injected into the DRN to study the direct effect of DRN orexin on SPA/EE. We found that the activation of orexin neurons elevates SPA/EE, and manipulation of GABA in the DRN does not alter the SPA response to orexin neuron activation. Similarly, intra-DRN orexin-A enhanced SPA and EE in the mice. These results suggest that orexin-A in the DRN facilitates negative energy balance by increasing physical activity-induced EE, and that modulation of DRN orexin-A is a potential strategy to promote SPA and EE.

Relationship of lumbar-hip kinematics during trunk flexion and sex, body mass index, and self-reported energy expenditure: a cross-sectional analysis

Purpose Physical activity (PA) is a well-known, simple and effective preventive and therapeutic intervention for low back pain (LBP). In spite of the growing interest in active lifestyles and its benefits, more needs to be known about the relationship between energy expenditure, body mass and lumbar-pelvic kinematics during the forward bending movement in a group of young asymptomatic people who met PA guidelines. Young people can be identified as a future risk group of civilisation diseases and lumbar-hip kinematics can be considered as a predictor of LBP occurrence. The aim of this study was to identify the association of sex, self-reported energy expenditure, body mass index, and lumbar-hip kinematics in young people. Methods Sixty-four students at pre-employment stage participated in the study. They declared moderate-to-high PA and activity-induced energy expenditure (AEE) was self-reported. Kinematic data of the lumbar spine, pelvis, and hip were collected during forward bending using a 3D motion capture system. Results Sex was found to be associated with pelvis (β=-0.38 p=0.002) and lumbar mobility (β=0.49, p<0.001) during forward bending and BMI was related only to lumbar mobility (β=-0.41, p=0.001). Recreation AEE significantly predicted hip flexion mobility (β =0.38, p=0.002). Conclusions This study showed that among a sample of physically active young people, BMI, self-reported AEE, and sex can partially predict lumbar-hip kinematics during trunk flexion. Recreational PA can be regarded as improving hip mobility and thus making forward bending more effective and less prone to injury.

Social Distancing During The Covid-19 Pandemic And Physical Activity In Older Women - An Accelerometer-based Analysis

The World Health Organization (WHO) recommends at least 30 minutes of MVPA per day for older adults to reduce the risk of hypertension and coronary heart disease. Older women with an increased cardiovascular risk may particularly benefit from physical activity, but social distancing measures may limit their opportunities to be physically active. Little is known about their physical activity (PA) behavior under varying social distancing responses to the COVID-19 pandemic. PURPOSE: The present study aimed to objectively assess the prevalence of PA in older women with an increased cardiovascular risk in Germany during two stages of social distancing measures. METHODS: The PA behavior of a non-representative sample of women aged 60 years and older living in North-Rhine Westphalia, Germany, was assessed twice using three-dimensional accelerometers worn at the hip for 10 days, at least 10 hours per day. Assessments were first performed between August and November 2020 in the context of light social distancing measures, and then repeated after 3-5 months starting from December 2020, when stricter social distancing policies were in place. Energy expenditure and time spent in MVPA was calculated from raw counts using the Freedson equation and cut-offs. SUMMARY OF RESULTS: A preliminary analysis of the data of n = 109 older women (68.8 ± 7.0 years) with mostly light cardiovascular risk showed an activity-induced energy expenditure of 304 ± 181 kcal/day, and a MET-rate of 1.20 ± 0.15 during light social distancing. Participants accumulated 44 ± 32 minutes of MVPA per day, with 68% surpassing 30 min of MVPA/day. CONCLUSION: First results indicate that despite light social distancing restrictions, a surprisingly high proportion of our sample of women aged 60 years and older reached WHO recommendations. It remains to be seen from the data collected between December 2020 and February 2021 if the participants were able to maintain their physical activity level during stricter social distancing policies.

Orexin in Dorsal Raphe Nucleus enhances Physical Activity and Energy Expenditure

Background Lateral hypothalamic (LH) orexin neurons modulate spontaneous physical activity (SPA), and energy expenditure (EE). Orexin deficiency results in weight gain, whereas heightened LH orexin sensitivity results in obesity resistance. Orexins act on multiple brain sites, including the serotonergic dorsal raphe nucleus (DRN), which receives excitatory projections from the orexin neurons. Our earlier studies show presence of both orexin-1 (OX1R) and orexin-2 receptors (OX2R) in DRN, and higher expression of OX1R and OX2R in DRN of obesity resistant (OR) rats. We hypothesized that orexin in DRN enhances SPA and EE. Secondarily, we hypothesized that DRN GABA (gamma-aminobutyric acid) signaling mediates the effect of orexin on SPA and EE. Methods We manipulated orexin tone in DRN either by direct injections of orexin A into DRN or by chemogenetic activation of LH orexin neurons in aged (~15 mo) orexin-cre mice. Mice were implanted with a guide cannula targeting DRN, and simultaneously prepared with the stimulatory (hM3Dq floxed) designer receptors exclusively activated by designer drugs (DREADD) virus in LH (N = 16). All mice recovered for 3 weeks to allow transfection of the DREADD virus, and randomly assigned to saline or clozapine N-oxide (CNO, DREADD activator) treatment. Mice were transferred to Promethion indirect calorimetry cages (Sable Systems International) to continuously monitor SPA and EE. Body weight and food intake were measured daily. After acclimation, mice received either IP vehicle or CNO (1 mg/kg) in a repeated measure design. Fifteen minutes prior to IP CNO or saline, animals were infused with either the GABA agonist muscimol (32.5 pmol/0.2 μl), GABA antagonist bicuculline (32.5 pmol/0.2 μl) or vehicle into DRN. In a separate experiment, either orexin A (250 pmol/0.2 μl) or saline was injected into DRN without IP CNO injection, to study the direct effect of DRN orexin on SPA and EE for 24h post-injection. Results We found that DREADD activation of LH orexin neurons increases SPA and EE. Manipulation of GABA receptors (by muscimol or bicuculline) in DRN did not affect orexin neuron activation induced enhancement of SPA. On the other hand, intra-DRN OXA enhanced SPA and EE in these mice up to 4h post-injection, without affecting food intake. Conclusions These results support the idea that OXA in DRN facilitates negative energy balance by increasing physical activity-induced energy expenditure. In addition, these data suggest that the DRN is a prominent site modulating OXA-stimulated SPA and EE, and that modulation of DRN OXA is a potential strategy to mitigate age-induced reductions in SPA and EE.

Total and activity-induced energy expenditure measured during a year in children with inflammatory bowel disease in clinical remission remain lower than in healthy controls.

Pediatric inflammatory bowel disease (IBD) is often associated with growth retardation due to malnutrition. However, knowledge on total energy expenditure (TEE), active-induced energy expenditure (AEE) and physical activity remains limited in children with IBD. Assessment of TEE using the doubly labelled water (DLW) method, resting energy expenditure (REE) using indirect calorimetry, and physical activity level using the actigraph GT3X+ in children with IBD (in remission) and healthy controls. TEE, REE, AEE and physical activity were measured in 21 children with IBD and 24 healthy controls at baseline. IBD children parameters were monitored further after 6 and 12 months. Predicted REE and TEE values (using Schoefield and the actigraph GT3X+, for REE and TEE respectively) were compared to measured values. Mean ages at baseline were 14.8±1.5 and 13.2±2 years in children with IBD and in healthy control children, respectively. Measured TEEDLW was significantly lower (P<0.001) in children with IBD compared to the healthy control group. REE corrected by FFM0.5, REE and AEE were also significantly lower in children with IBD. Children with IBD had AEE of 17.5% of TEE and had a significantly higher sedentary behaviour as compared to healthy children. This study suggests that TEE and AEE are reduced in children with IBD in clinical remission which may result in a reduced moderate and vigorous physical activity level. Our result also highlights that the actigraph GT3X+might give good prediction of TEE in children with IBD at group level but it remains highly variable at individual level.

Validity of Combination Use of Activity Record and Accelerometry to Measure Free-Living Total Energy Expenditure in Female Endurance Runners.

Yoshida, A, Ishikawa-Takata, K, Tanaka, S, Suzuki, N, Nakae, S, Murata, H, Taguchi, M, and Higuchi, M. Validity of combination use of activity record and accelerometry to measure free-living total energy expenditure in female endurance runners. J Strength Cond Res 33(11): 2962-2970, 2019-Herein, we attempted to prove the validity of a new approach to assessing total energy expenditure (TEE) that combines activity recording and accelerometry in athletes. Eight female endurance runners participated in this study. We measured TEE over 8 days in the regular training season by using the doubly labeled water (DLW) method. In the combined method, an activity record of the rating of perceived exertion (RPE) was used to estimate energy expenditure (EE) during the training period, whereas a triaxial accelerometer was used to evaluate EE during the nontraining time over the TEE measurement period using the DLW method. Training EE was calculated from the subjects' individual rating of perceived exertion-EE correlations provided by the exercise tolerance test. Resting metabolic rate (RMR) was measured using indirect calorimetry. There were no significant differences in TEE, activity-induced EE (AEE), or physical activity level (PAL; TEE/RMR) between the DLW method and the combined method (TEE, 3,032 ± 344 vs. 3,033 ± 495 kcal·d; AEE, 1,585 ± 303 vs. 1,586 ± 442 kcal·d; and PAL, 2.68 ± 0.37 vs. 2.68 ± 0.48, respectively). Significant positive correlations and no systematic errors were observed in AEE and PAL. Intraclass correlation coefficients were high (TEE, 0.785; AEE, 0.841; and PAL, 0.779, respectively). These findings suggest that the combined method has high validity against the DLW method. Thus, the combined method would be able to estimate free-living TEE in the regular training season for female endurance runners.

Training-induced changes in daily energy expenditure: Methodological evaluation using wrist-worn accelerometer, heart rate monitor, and doubly labeled water technique.

IntroductionWrist-mounted motion sensors can quantify the volume and intensity of physical activities, but little is known about their long-term validity. Our aim was to validate a wrist motion sensor in estimating daily energy expenditure, including any change induced by long-term participation in endurance and strength training. Supplemental heart rate monitoring during weekly exercise was also investigated.MethodsA 13-day doubly labeled water (DLW) measurement of total energy expenditure (TEE) was performed twice in healthy male subjects: during two last weeks of a 12-week Control period (n = 15) and during two last weeks of a 12-week combined strength and aerobic Training period (n = 13). Resting energy expenditure was estimated using two equations: one with body weight and age, and another one with fat-free mass. TEE and activity induced energy expenditure (AEE) were determined from motion sensor alone, and from motions sensor combined with heart rate monitor, the latter being worn during exercise only.ResultsWhen body weight and age were used in the calculation of resting energy expenditure, the motion sensor data alone explained 78% and 62% of the variation in TEE assessed by DLW at the end of Control and Training periods, respectively, with a bias of +1.75 (p <.001) and +1.19 MJ/day (p = .002). When exercise heart rate data was added to the model, the combined wearable device approach explained 85% and 70% of the variation in TEE assessed by DLW with a bias of +1.89 and +1.75 MJ/day (p <.001 for both). While significant increases in TEE and AEE were detected by all methods as a result of participation in regular training, motion sensor approach underestimated the change measured by DLW: +1.13±0.66 by DLW, +0.59±0.69 (p = .004) by motion sensor, and +0.98±0.70 MJ/day by combination of motion sensor and heart rate. Use of fat-free mass in the estimation of resting energy expenditure removed the biases between the wearable device estimations and the golden standard reference method of TEE and demonstrated a training-induced increase in resting energy expenditure by +0.18±0.13 MJ/day (p <.001).ConclusionsWrist motion sensor combined with a heart rate monitor during exercise sessions, showed high agreement with the golden standard measurement of daily TEE and its change induced by participation in a long-term training protocol. The positive findings concerning the validity, especially the ability to follow-up the change associated with a lifestyle modification, can be considered significant because they partially determine the feasibility of wearable devices as quantifiers of health-related behavior.

Seasonal variation in body mass, body composition and activity-induced energy expenditure: a long-term study.

Seasonal variation in body mass is a model for the study of body mass regulation. Here a long-term study is presented on body mass, body composition, and activity-induced energy expenditure in a subject with a large seasonal variation in body mass of about 3.0 kg. Body mass was assessed daily over >20 consecutive years. Daily assessment of activity-induced energy expenditure was performed over the last 10 years. Body composition was assessed monthly for 1 year in the middle and at the end of the observation interval. Additionally, data were compared with data on body composition, resting energy expenditure, and total daily energy expenditure of the same subject as a participant in published studies. Body mass showed a pronounced seasonal variation, associated with a synchronous variation in physical activity. Body mass peaked in the cold winter months when physical activity reached the lowest annual value and decreased to the lowest value in mid-summer when daily physical activity peaked. The seasonal variation in body mass consisted mainly of body fat. Longitudinally, over the past 8 years of the observation interval, average fat-free mass showed a decrease of 1.0 kg and fat mass increased 0.8 kg. In a subject with a pronounced seasonal variation in physical activity, activity-induced variation in energy requirement was covered by an annual variation in body mass, mainly as fat. Maintenance of activity-induced energy expenditure did not protect against loss of fat-free body mass with advancing age.

Changes in physical activity over the lifespan: impact on body composition and sarcopenic obesity.

Physical activity and body composition show a typical pattern over the lifecycle. Fat-free mass and physical performance generally peak in early adulthood. Here, evidence for a relation between physical activity changes over the life span and the development of sarcopenic obesity is presented. Activity-induced energy expenditure increases with body size and physical activity during growth. The physical activity level, calculated by expressing total energy expenditure as a multiple of resting energy expenditure, gradually increases from early age to adulthood to decrease again in old age. Habitual physical activity has a significant effect on growth of fat-free mass during adolescence and thus on peak fat-free mass and physical performance in early adulthood. Older subjects have a lower fat-free mass and lower physical activity levels but there is no association, suggesting physical activity does not protect against loss of lean body mass at higher age. Prevention of sarcopenic obesity starts with a physically active lifestyle to develop a healthy peak fat-free mass and subsequent prevention of excess fat gain. The change from a physically active to a more sedentary routine in later life requires restriction of energy intake to maintain energy balance.

The effect of glucagon-like peptide 1 and glucagon-like peptide 1 receptor agonists on energy expenditure: A systematic review and meta-analysis

AimWe reviewed clinical trials addressing the effect of glucacon-like peptide 1 (GLP-1) or GLP-1 receptor agonists (GLP-1RA) on energy expenditure (EE) in adults. Materials and methodsPubMed, Science Direct and Web of Science were searched for clinical trials investigating the effect of GLP-1 or GLP-1RA on EE in adults. ResultsTen trials (93 participants) assessed the effect of GLP-1 administration over 1 to 48 h and found no change in resting EE (REE). Two out of three trials (62 participants) reported a significant decrease in diet-induced thermogenesis (DIT) following GLP-1 administration. Ten trials with exenatide (10 μg bid, for 10–52 weeks) or liraglutide (0.6, 1.2, 1.8 or 3 mg, for 3 days-52 weeks), with a total of 282 participants, indicated a neutral effect of these GLP-1RA on REE, DIT or physical activity-induced EE. Importantly, the longest trial with GLP-1RA reported a significant increase in REE in response to treatment with both exenatide or liraglutide and most trials reported that GLP-1RA-induced weight loss was not accompanied by decreased REE. ConclusionsThis review indicates that GLP-1 has no short-term effect on REE but may decrease DIT. The GLP-1RA exenatide and liraglutide have a neutral effect on REE, although it is not possible to rule out an increase in REE following prolonged treatment.

A Decision-tree Model For Classifying Physical Activity Types Using A Three-axis Accelerometer In Japanese Adults

Accelerometry is a valid method for assessing physical activity in free-living conditions. Although there are numerous studies on estimating physical activity-induced energy expenditure (PAEE), classification of physical activity types using an accelerometer is not well established. PURPOSE: To develop a physical activity classification model using a three-axis accelerometer in Japanese subjects. METHODS: Eleven healthy adults (age, 33.3±10.4 years) stayed in a human calorimeter for 23 hours and performed activities (sitting, standing, walking, lying down) while wearing a three-axis accelerometer (Actigraph-wGT3X-BT). Raw three-axis acceleration values were obtained at 30 Hz. Raw acceleration values were processed into five feature quantities: filtered acceleration values (FAC), raw acceleration values (RAC), absolute value of filtered accelerations (ABS), standard deviation of FAC (SD), and peak-to-peak of FAC (PP). A classification model was proposed using a decision tree and an 11-fold cross-validation method with time resolutions of 1, 5, or 10 seconds. RESULTS: The classification model achieved the following accuracy levels for each time segment for all activities: 75.1% with 1-second segments, 76.1% with 5-second segments, and 77.7% with 10-second segments. Selected feature quantities in these models were RAC, ABS, and PP in 1-second segments; FAC, RAC, ABS, SD, and PP in 5-second segments, and FAC, RAC, and PP in 10-second segments. The classification model with a 10-second time resolution had better accuracy than with 5- or 1-second time resolution. The model’s accuracy for each type of physical activity with 10-second segments was 80.6% for sitting, 59.6% for standing, 99.7% for walking, and 84.1% for lying down. CONCLUSIONS: These results suggest that the decision tree is a valid method for physical activity classification in Japanese subjects. The addition of other features and classification methods, e.g., random forest, needs to be discussed in future studies.

Diurnal Patterns of Physical Activity in Relation to Activity Induced Energy Expenditure in 52 to 83 Years-Old Adults.

BackgroundAgeing is associated with a declining physical activity level (PAL) and changes in the diurnal activity pattern. Changes in the activity pattern might help explaining the age-associated reduction of physical activity.ObjectiveThe aims were to investigate diurnal activity patterns within groups of older adults classified by PAL, to investigate diurnal activity patterns within age-groups and to investigate the association between the drop in activity and aerobic fitness.MethodsThirty-one healthy subjects aged between 52 and 83y were recruited for the study. Subjects were divided in sedentary (PAL<1.75), moderately active (1.75<PAL<1.90), and active (1.90<PAL) older adults with energy expenditure measurements obtained with the doubly labelled water technique. Diurnal activity patterns were based on activity counts from an accelerometer during wake time and then divided in four quarters of equal time length. Additionally, aerobic fitness was measured as maximal oxygen uptake.ResultsSubjects had a PAL between 1.43 and 2.34 and an aerobic fitness between 18 and 49 ml/kg/min. Overall, activity patterns showed a peak in the first quarter of wake time (around 10AM) followed by a gradual decline of, on average, 5% per hour. Active subjects reached their peak in the first quarter and remained active until after the third quarter (11% drop each quarter on average). Moderately active and sedentary subjects reached their peak during the second quarter with a decrease during the third quarter (respectively 29% and 17% drop each quarter on average). The drop in physical activity between the first and the second half of the wake time was negatively associated with aerobic fitness (r = -0.39, p<0.05).ConclusionActive older adults maintained a larger amount of body movement for longer during their wake time. Diurnal physical activity declined more in adults ≥66 years old with lower aerobic fitness.

Leptin and energy restriction induced adaptation in energy expenditure

BackgroundDiet-induced weight loss is accompanied by adaptive thermogenesis, i.e. a disproportional reduction of resting energy expenditure (REE) a decrease in physical activity and increased movement economy. ObjectiveTo determine if energy restriction induced adaptive thermogenesis and adaptations in physical activity are related to changes in leptin concentrations. MethodsEighty-two healthy subjects (23 men, 59 women), mean±SD age 41±8years and BMI 31.9±3.0kg/m2, followed a very low energy diet for 8weeks with measurements before and after the diet. Leptin concentrations were determined from fasting blood plasma. Body composition was assessed with a three-compartment model based on body weight, total body water (deuterium dilution) and body volume (BodPod). REE was measured (REEm) with a ventilated hood and predicted (REEp) from measured body composition. Adaptive thermogenesis was calculated as REEm/REEp. Parameters for the amount of physical activity were total energy expenditure expressed as a multiple of REEm (PAL), activity-induced energy expenditure divided by body weight (AEE/kg) and activity counts measured by a tri-axial accelerometer. Movement economy was calculated as AEE/kg (MJ/kg/d) divided by activity counts (Mcounts/d). ResultsSubjects lost on average 10.7±4.1% body weight (P<0.001). Leptin decreased from 26.9±14.3 before to 13.9±11.3μg/l after the diet (P<0.001). REEm/REEp after the diet (0.963±0.08) was related to changes in leptin levels (R2=0.06; P<0.05). There was no significant correlation between changes in leptin concentrations and changes in amount of physical activity. Movement economy changed from 0.036±0.011J/kg/count to 0.028±0.010J/kg/count and was correlated to the changes in leptin concentrations (R2=0.07; P<0.05). ConclusionDuring energy restriction, the decrease in leptin explains part of the variation in adaptive thermogenesis. Changes in leptin are not related to the amount of physical activity but could partly explain the increased movement economy.

Weight loss–induced reduction in physical activity recovers during weight maintenance

Weight loss due to a negative energy balance is considered to be accompanied by a decrease in physical activity. The aim of this study was to investigate whether a decrease in physical activity is sustained during weight maintenance. Subjects were 20 men and 31 women [mean (±SD) age: 42 ± 8 y; BMI (in kg/m(2)): 31.4 ± 2.8]. Weight loss was achieved by an 8-wk very-low-energy diet period, followed by 44 wk of weight maintenance. Physical activity measures were total energy expenditure expressed as a multiple of sleeping metabolic rate (PALSMR) and resting metabolic rate (PALRMR), activity-induced energy expenditure divided by body weight (AEE/kg), and activity counts measured by a triaxial accelerometer. Measurements took place at 0, 8, and 52 wk. Body mass decreased significantly during the diet period (10.5 ± 3.8%, P < 0.001), and this reduction was sustained after 52 wk (6.0 ± 5.1%, P < 0.001). PALSMR and PALRMR decreased from 1.81 ± 0.23 and 1.70 ± 0.22, respectively, before the diet to 1.69 ± 0.20 and 1.55 ± 0.19 after the diet (P < 0.001) and increased again after weight maintenance to 1.85 ± 0.27 and 1.71 ± 0.23, respectively, compared with 8-wk measurements (P < 0.001). AEE/kg decreased from 0.043 ± 0.015 MJ/kg at baseline to 0.037 ± 0.014 MJ/kg after the diet (P < 0.001) and was higher after 52 wk (0.044 ± 0.17 MJ/kg) compared with after 8 wk (P < 0.001). Activity counts decreased from 1.64 ± 0.37 megacounts/d at baseline to 1.54 ± 0.35 megacounts/d after the diet (P < 0.05) and were higher after 52 wk (1.73 ± 0.49 megacounts/d) compared with 8 wk (P < 0.01). A weight loss-induced reduction in physical activity returns to baseline values when weight loss is maintained. This trial was registered at clinicaltrials.gov as NCT01015508.

Disadvantageous shift in energy balance is primarily expressed in high-quality sleepers after a decline in quality sleep because of disturbance

Epidemiologic studies have shown an inverse or U-shaped relation between sleep duration and body mass index (BMI; in kg/m(2)). Moreover, associations between energy balance (EB) and characteristics of quality sleep (QS) have recently been reported. We assessed the relation between total energy expenditure (TEE) as well as substrate oxidation and QS after disturbed compared with nondisturbed sleep in EB. Fifteen healthy men (mean ± SD BMI: 24.1 ± 1.9; age: 23.7 ± 3.5 y) were included in a randomized crossover study. TEE and substrate oxidation were measured twice for 48 h in a respiration chamber, whereas slow-wave sleep (SWS), rapid eye movement (REM)-sleep, total sleeping time (TST), sleep stage 2 (S2), and QS [(SWS + REM) ÷ TST × 100%] were determined by using electroencephalography. During 2 nights, sleep (2330-0730) was either disturbed or nondisturbed (control). Positive correlations were shown for TEE, activity-induced energy expenditure corrected for body mass (AEE/BM), respiratory quotient (RQ), and carbohydrate oxidation with QS and SWS during nondisturbed sleep. Fat oxidation was inversely correlated with QS and SWS. RQ and carbohydrate oxidation were inversely related to REM sleep. During the disturbed condition SWS, REM, TST, and S2 were reduced, and positive correlations were shown between TEE and AEE/BM with QS. The reduction in QS was stronger in high-quality sleepers; QS reduction was positively associated with increases in energy intake, TEE, and EB. A disadvantageous shift in energy balance is primarily expressed in high-quality sleepers after a decline in QS because of disturbance, implying that good sleepers are most liable to a positive energy balance because of sleep disturbance. This trial was registered at ISRCTN as NTR1919.

Free-living physical activity and energy expenditure of rural children and adolescents in the Nandi region of Kenya

Purpose: To examine the relationship between physical activity and energy demands in children and adolescents with highly active lifestyles.Methods: Physical activity patterns of 30 rural Kenyan children and adolescents (14 ± 1 years, mean ± SD) with median body mass index (BMI) z-score = −1.06 [−3.29–0.67] median [range] were assessed by accelerometry over 1 week. Daily energy expenditure (DEE), activity-induced energy expenditure (AEE) and physical activity level (PAL) were simultaneously determined using doubly-labelled water (DLW). Active commuting to school was assessed by global positioning system.Results: Mean DEE, AEE and PAL were 12.2 ± 3.4, 5.7 ± 3.0 MJ/day and 2.3 ± 0.6, respectively. A model combining body mass, average accelerometer counts per minute and time in light activities predicted 45% of the variance in DEE (p < 0.05) with a standard error of DEE estimate of 2.7 MJ/day. Furthermore, AEE accounted for ∼47% of DEE. Distance to school was not related to variation in DEE, AEE or PAL and there was no association between active commuting and adiposity.Conclusion: High physical activity levels were associated with much higher levels of energy expenditure than observed in Western societies. These results oppose the concept of physical activity being stable and constrained in humans.

Aerobic Capacity, Activity Levels and Daily Energy Expenditure in Male and Female Adolescents of the Kenyan Nandi Sub-Group

The relative importance of genetic and socio-cultural influences contributing to the success of east Africans in endurance athletics remains unknown in part because the pre-training phenotype of this population remains incompletely assessed. Here cardiopulmonary fitness, physical activity levels, distance travelled to school and daily energy expenditure in 15 habitually active male (13.9±1.6 years) and 15 habitually active female (13.9±1.2) adolescents from a rural Nandi primary school are assessed. Aerobic capacity () was evaluated during two maximal discontinuous incremental exercise tests; physical activity using accelerometry combined with a global positioning system; and energy expenditure using the doubly labelled water method. The of the male and female adolescents were 73.9±5.7 ml. kg−1. min−1 and 61.5±6.3 ml. kg−1. min−1, respectively. Total time spent in sedentary, light, moderate and vigorous physical activities per day was 406±63 min (50% of total monitored time), 244±56 min (30%), 75±18 min (9%) and 82±30 min (10%). Average total daily distance travelled to and from school was 7.5±3.0 km (0.8–13.4 km). Mean daily energy expenditure, activity-induced energy expenditure and physical activity level was 12.2±3.4 MJ. day−1, 5.4±3.0 MJ. day−1 and 2.2±0.6. 70.6% of the variation in was explained by sex (partial R2 = 54.7%) and body mass index (partial R2 = 15.9%). Energy expenditure and physical activity variables did not predict variation in once sex had been accounted for. The highly active and energy-demanding lifestyle of rural Kenyan adolescents may account for their exceptional aerobic fitness and collectively prime them for later training and athletic success.

Physical activity and physical activity induced energy expenditure in humans: measurement, determinants, and effects

Physical activity is defined as any bodily movement produced by skeletal muscles that results in energy expenditure. The doubly labeled water method for the measurement of total energy expenditure (TEE), in combination with resting energy expenditure, is the reference for physical activity under free-living conditions. To compare the physical activity level (PAL) within and between species, TEE is divided by resting energy expenditure resulting in a figure without dimension. The PAL for sustainable lifestyles ranges between a minimum of 1.1–1.2 and a maximum of 2.0–2.5. The average PAL increases from 1.4 at age 1 year to 1.7–1.8 at reproductive age and declines again to 1.4 at age 90 year. Exercise training increases PAL in young adults when energy balance is maintained by increasing energy intake. Professional endurance athletes can reach PAL values around 4.0. Most of the variation in PAL between subjects can be ascribed to predisposition. A higher weight implicates higher movement costs and less body movement but not necessarily a lower PAL. Changes in physical activity primarily affect body composition and to a lesser extent body weight. Modern man has a similar PAL as a wild mammal of a similar body size.

Metabolic adaptations to over—and underfeeding—still a matter of debate?

Weight changes in response to a change in energy intake are smaller than calculated from the excess or deficit of energy intake. Digestion efficiency is not affected by intake level when consuming the same diet. Over- or underfeeding induces an increase or decrease in energy expenditure. Intake-induced expenditure changes are largely explained by proportional changes in diet-induced energy expenditure, in activity-induced energy expenditure and in maintenance expenditure as a function of changes in body weight and body composition. Additionally, underfeeding causes a metabolic adaptation as reflected in a reduction of maintenance expenditure below predicted values and defined as adaptive thermogenesis. Thus, alternating overfeeding and underfeeding with an iso-energetic amount results in a positive energy balance. The latter might be one of the explanations for the increasing incidence of obesity in our current society with an ample food supply.

Wrist-worn accelerometers in assessment of energy expenditure during intensive training

We assessed the ability of the Polar activity recorder (AR) to measure energy expenditure (EE) during military training. Twenty-four voluntary male conscripts participated in the study and wore an AR on the non-dominant wrist 24 h a day for 7 d. The AR analyzed and stored the frequency of hand movements (f_hand) into memory at 1 min intervals. The relationship between f_hand and EE was studied over a 7 d period of military training using the doubly labeled water (DLW) technique. In addition, the relationship between f_hand and EE was analyzed during walking and running on a treadmill with an indirect calorimeter (IC), and f_hand was measured during a supervised 45 min field march test where the conscripts carried combat gear. EE was expressed as physical activity level (PAL), total energy expenditure (TEE), and activity-induced energy expenditure adjusted for body mass (AEE/BM). Over the 7 d period, f_hand alone explained 46% of inter-individual variation in PALDLW. After inclusion of body height and mass in the model used to predict PALDLW from f_hand, a very high positive correlation and a low standard error of estimate (SEE) were observed between the AR and DLW techniques: for TEE r = 0.86 (p < 0.001), the SEE was 6.3%, and for AEE/BM r = 0.84 (p < 0.001), the SEE was 12.8%. In the treadmill exercise, f_hand correlated highly with PALIC (r = 0.97 ± 0.02). In the 45 min field march test, the AR measured similar f_hand as on the treadmill at the same speed. In conclusion, the wrist-worn AR can be regarded as a reliable and valid method for assessing EE during intensive training.