Sedentary behavior (SB) has detrimental consequences and cannot be compensated for through moderate-to-vigorous physical activity (PA). In order to understand and mitigate SB, tools for measuring and ...monitoring SB are essential. While current direct-to-customer wearables focus on PA, the VitaBit validated in this study was developed to focus on SB. It was tested in a laboratory and in a free-living condition, comparing it to direct observation and to a current best-practice device, the ActiGraph, on a minute-by-minute basis. In the laboratory, the VitaBit yielded specificity and negative predictive rates (NPR) of above 91.2% for sitting and standing, while sensitivity and precision ranged from 74.6% to 85.7%. For walking, all performance values exceeded 97.3%. In the free-living condition, the device revealed performance of over 72.6% for sitting with the ActiGraph as criterion. While sensitivity and precision for standing and walking ranged from 48.2% to 68.7%, specificity and NPR exceeded 83.9%. According to the laboratory findings, high performance for sitting, standing, and walking makes the VitaBit eligible for SB monitoring. As the results are not transferrable to daily life activities, a direct observation study in a free-living setting is recommended.
ObjectivesTo quantify energy expenditure and intake in professional female footballers playing on a national and/or international level. Second, to determine the prevalence of low energy availability ...among these players, defined as <30 kcal/kg fat-free mass (FFM)/day.MethodsFifty-one players completed a 14-day prospective observational study during the 2021/2022 football season. Energy expenditure was determined using the doubly labelled water method. Energy intake was assessed using dietary recalls, while global positioning system determined the external physiological load. Descriptive statistics, stratification and the correlation between explainable variables and outcomes were conducted to quantify the energetic demands.ResultsThe mean energy expenditure for all players (22±4 years) was 2918±322 kcal. Mean energy intake was 2274±450 kcal, resulting in a discrepancy of ~22%. Carbohydrate intake was below the recommended guidelines on match day at 4.5±1.9 g/kg. The mean energy availability was 36.7±17.7 kcal/kg FFM/day on matchday and 37.9±11.7 kcal/kg FFM/day on training days, resulting in a prevalence of 36% and 23% for low energy availability during the observational period, respectively.ConclusionThese elite female football players displayed moderate energy expenditure levels and failed to meet the recommended levels of carbohydrate intake. In conjunction with inadequate nutritional periodisation, this will likely hamper performance through inadequate muscle glycogen resynthesis. In addition, we found a considerable prevalence of low energy availability on match and training days.
Physical activity and human energy expenditure Westerterp, Klaas R; Plasqui, Guy
Current opinion in clinical nutrition and metabolic care,
2004-November, 2004-Nov, 2004-11-00, 20041101, Letnik:
7, Številka:
6
Journal Article
Recenzirano
Odprti dostop
PURPOSE OF REVIEWThis is a review on the measurement of physical activity under daily life conditions. The focus is on the doubly labelled water method and accelerometry. Doubly labelled water is a ...gold standard and the reference for the validation of field methods to assess physical activity. Accelerometry is the most objective and precise technique to assess activity patterns in terms of frequency, duration and intensity. Applications of the two techniques are illustrated with the limits of physical activity and energy expenditure and with activity intensity as a determinant of the physical activity level.
RECENT FINDINGSThe upper limit of the physical activity index (total energy expenditure as a multiple of basal metabolic rate) of 2.5, as derived from cross-sectional data, is confirmed by training intervention studies. Exercise training, in which total energy expenditure was measured before and at the end of the training programme, showed no increase in physical activity index when training was combined with an energy restricted diet and in elderly subjects. In children, the distribution of time spent at activities with low and high intensity determines the physical activity index while in adults moderate-intensity activities are the main determinant.
SUMMARYIn adults, within the normal physical activity index range, the distribution of time spent at activities with low and moderate intensity determines the physical activity level. High-intensity activity does not have much impact on daily energy expenditure. High-intensity activity is not required to increase the activity energy expenditure.
Any change in the energetic cost of mammalian mastication will affect the net energy gain from foods. Although the energetic efficiency of masticatory effort is fundamental in understanding the ...evolution of the human masticatory system, nothing is known currently about the associated metabolic costs of chewing different items. Here, using respirometry and electromyography of the masseter muscle, we demonstrate that chewing by human subjects represents a measurable energy sink. Chewing a tasteless odorless gum elevates metabolic rate by 10 to 15% above basal levels. Energy expenditure increases with gum stiffness and is paid for by greater muscle recruitment. For modern humans, it is likely that mastication represents a small part of the daily energy budget. However, for our ancestors, before the onset of cooking and sophisticated food processing methods, the costs must have been relatively high, adding a previously unexplored energetic dimension to the interpretation of hominin dentofacial fossils.
Determining the energetic cost of mastication in humans sheds light on the evolution of the human feeding system.
Increasing age is associated with declining physical activity and a gain in fat mass. The objective was to observe the consequence of the age-associated reduction in physical activity for the ...maintenance of energy balance as reflected in the fat store of the body.
Young adults were observed over an average time interval of more than 10 years. Physical activity was measured over two-week periods with doubly labeled water and doubly labeled water validated triaxial accelerometers, and body fat gain was measured with isotope dilution. There was a significant association between the change in physical activity and the change in body fat, where a high initial activity level was predictive for a higher fat gain.
The change from a physically active to a more sedentary routine does not induce an equivalent reduction of energy intake and requires cognitive restriction to maintain energy balance.
Background
Brown adipose tissue (BAT) has been primarily researched as a potential target for mitigating obesity. However, the physiological significance of BAT in relation to cachexia remains poorly ...understood. The objective of this study was to investigate the putative contribution of BAT on different components of energy metabolism in emphysematous chronic obstructive pulmonary disease (COPD) patients.
Methods
Twenty COPD patients (mean ± SD age 62 ± 6, 50% female, median range BMI 22.4 15.1–32.5 kg/m2 and 85% low FFMI) were studied. Basal metabolic rate (BMR) was assessed by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water and physical activity by triaxial accelerometry. BMR was adjusted for fat‐free mass (FFM) as assessed by deuterium dilution. Analysis of BAT and WAT was conducted in a subset of ten patients and six age‐matched, gender‐matched and BMI‐matched healthy controls. BAT glucose uptake was assessed by means of cold‐stimulated integrated 18FFDG positron‐emission tomography and magnetic resonance imaging. WAT was collected from subcutaneous abdominal biopsies to analyse metabolic and inflammatory gene expression levels. Lung function was assessed by spirometry and body plethysmography and systemic inflammation by high sensitivity C‐reactive protein.
Results
Mean TDEE was 2209 ± 394 kcal/day, and mean BMR was 1449 ± 214 kcal/day corresponding to 120% of predicted. FFM‐adjusted BMR did not correlate with lung function or C‐reactive protein. Upon cooling, energy expenditure increased, resulting in a non‐shivering thermogenesis of (median range) 20.1% 3.3–41.3 in patients and controls. Mean BAT glucose uptake was comparable between COPD and controls (1.5 0.1–6.2 vs. 1.1 0.7–3.9). In addition, no correlation was found between BMR adjusted for FFM and BAT activity or between cold‐induced non‐shivering energy expenditure and BAT activity. Gene expression levels of the brown adipocyte or beige markers were also comparable between the groups. No (serious) adverse events were reported.
Conclusions
Although COPD patients were hypermetabolic at rest, no correlation was found between BMR or TDEE and BAT activity. Furthermore, both BAT activity and gene expression levels of the brown adipocyte or beige markers were comparable between COPD patients and controls.
OBJECTIVES: There has been a rise in the number of overweight women across the globe and sub-Saharan Africa has not been spared. Our objective was to describe the performance of household food ...security as a factor in determining overweight and underweight among Kenyan women of child-bearing age. DESIGN: A cross sectional survey using a structured questionnaire was carried out among 656 households with women of child-bearing age from both rural and urban settings in the Rift Valley, Kenya. RESULTS: Of all households involved, 70.1% were categorized as severely food insecure, 21.9% were moderately food insecure, and 3.7% were mildly food insecure, whereas 4.3% were food secure. Urban women had higher mean BMI (M = 24.53, SD = 4.36), compared to rural women (M = 22.52, SD = 3.71; P <0.000). Households with more children had decreased dietary diversity (r = -0.154; P <0.01). Logistical regression indicated that more food-secure households (OR = 0.97; 95% CI 9.4, 1.0), urban residence (OR = 1.82; 95% CI 1.1, 3.0), older age (OR = 1.10; 95% CI 1.1, 1.5), and high standard of living (OR = 1.79; 95% CI 1.2, 1.5) were strong predictors of overweight while being underweight was predicted by younger age (OR = 0.91; 95% CI, 0.83, 1.0). CONCLUSIONS: A food-secure household does not predict underweight but predicts overweight among women.
Objective: The impact of season on energy expenditure and physical activity is not well quantified. This study focused on summer‐winter differences in total energy expenditure (TEE) and physical ...activity.
Research Methods and Procedures: Twenty‐five healthy Dutch young adults, living in an urban environment, were measured in the summer season and the winter season. TEE was measured using doubly labeled water, and sleeping metabolic rate (SMR) was measured during an overnight stay in a respiration chamber. Subsequently, the physical activity level (PAL = TEE/SMR) and activity‐related energy expenditure (0.9 × TEE) − SMR were calculated. Maximal mechanical power (Wmax) was determined with an incremental test on a cycle ergometer. Body composition was measured with hydrostatic weighing and deuterium dilution using Siri's three‐compartment model.
Results: There was no difference in TEE between seasons. PAL was higher in summer than in winter (1.87 ± 0.22 vs. 1.76 ± 0.18; p < 0.001), and the difference was higher for men than for women (0.20 ± 0.14 vs. 0.05 ± 0.16; p = 0.04). The difference in PAL between seasons was dependent on the initial activity level. There was a strong linear relation (R2 = 0.48) between PAL and physical fitness (Wmax/fat‐free mass), but Wmax/fat‐free mass did not change between seasons in response to the lower PAL in winter.
Discussion: The extent of the changes in PAL is of physiological significance, and seasonality in physical activity should be taken into account when studying physical activity patterns or relationships between physical activity and health.
Background and Aim. Increasing energy expenditure is an effective strategy for the prevention of obesity. In this respect, Lycium barbarum (goji berry) is of interest, as it has been shown to ...increase postprandial oxygen consumption. Although this suggests that energy expenditure was also increased, energy expenditure and substrate oxidation can only be assessed accurately when both oxygen consumption and carbon dioxide production are measured. We therefore investigated the effects of a single dose of Lycium barbarum fruit on postprandial energy expenditure and substrate oxidation in a randomized, double-blind crossover trial. In addition, markers of lipid and glucose metabolism were measured. Methods. Seventeen healthy, overweight men received in a random order a meal containing 25 grams of dried Lycium barbarum fruit or a control meal matched for caloric content and macronutrient composition. Energy expenditure and the respiratory quotient were determined using indirect calorimetry before and up to 4 hours after meal intake. Blood was sampled before and after meal intake at regular intervals for analyses of plasma glucose, serum triacylglycerol, and free fatty acid concentrations. Results. Energy expenditure significantly increased after the Lycium barbarum and control meal, but no differences were found between the meals (p=0.217). Postprandial changes in respiratory quotient (p=0.719) and concentrations of glucose (p=0.663), triacylglycerol (p=0.391), and free fatty acids (p=0.287) were also not affected by Lycium barbarum intake. Conclusions. A single dose of Lycium barbarum does not affect postprandial energy expenditure, substrate oxidation, and markers for lipid and glucose metabolism in healthy, overweight men.
This review focuses on the ability of different accelerometers to assess daily physical activity as compared with the doubly labeled water (DLW) technique, which is considered the gold standard for ...measuring energy expenditure under free‐living conditions. The PubMed Central database (U.S. NIH free digital archive of biomedical and life sciences journal literature) was searched using the following key words: doubly or double labeled or labeled water in combination with accelerometer, accelerometry, motion sensor, or activity monitor. In total, 41 articles were identified, and screening the articles’ references resulted in one extra article. Of these, 28 contained sufficient and new data. Eight different accelerometers were identified: 3 uniaxial (the Lifecorder, the Caltrac, and the CSA/MTI/Actigraph), one biaxial (the Actiwatch AW16), 2 triaxial (the Tritrac‐R3D and the Tracmor), one device based on two position sensors and two motion sensors (ActiReg), and the foot‐ground contact pedometer. Many studies showed poor results. Only a few mentioned partial correlations for accelerometer counts or the increase in R2 caused by the accelerometer. The correlation between the two methods was often driven by subject characteristics such as body weight. In addition, standard errors or limits of agreement were often large or not presented. The CSA/MTI/Actigraph and the Tracmor were the two most extensively validated accelerometers. The best results were found for the Tracmor; however, this accelerometer is not yet commercially available. Of those commercially available, only the CSA/MTI/Actigraph has been proven to correlate reasonably with DLW‐derived energy expenditure.
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