Physical Energy Expenditure Research Articles

Physical activity levels and energy expenditure of 9-year-old – 12-year-old overweight and obese children

The high occurrence of overweight and obesity amongst children is a disturbing health problem worldwide. Possible causes of increasing childhood obesity are inactivity and energy imbalances. The aim of this study was to analyse the total energy expenditure (TEE)and physical activity levels in 9-year-old – 12-year-old overweight and obese children during a weekday and a weekend day, as well as during a weekday morning and afternoon. Twenty-four 9-year-old – 12-year-old children (seven boys and 17 girls), of whom nine were overweight and 15 were obese, were selected from seven public primary schools for this study. Body mass index (BMI) cut-off points were used to distinguish between overweight and obese. Each participant wore an ACTICAL™ monitor to determine their physical activity levels and TEE. It was found that the TEE of the children did not differ between a week day and a weekend day, although the TEE of the week day afternoon differed significantly from that of the weekday morning. Unlike the overweight children, none of the obese children met the requirements of 60 minutes of moderate-intensity physical activity per day. Strategies should be found to increase the activity levels of overweight and, especially, obese children, specifically during the mornings and over weekends.OpsommingDie hoë voorkoms van oorgewig en obesiteit onder kinders is wêreldwyd ’n kommerwekkende gesondheidsprobleem. Fisieke onaktiwiteit en energiewanbalanse word as moontlike oorsake van die probleem beskou. Die doel van hierdie studie was om die totale energieverbruik (TEV) en fisieke-aktiwiteitsvlakke van 9-jarige – 12-jarige oorgewig- en obese kinders tydens ‘n totale weeksdag en naweekdag te ontleed, asook tydens die oggend en middag van ‘n weeksdag. Vier-en-twintig 9-jarige – 12-jarige kinders (sewe seuns en 17 dogters), waarvan nege oorgewig en 15 obees was, is uit sewe publieke laerskole vir die studie gekies. Afsnypunte volgens die liggaamsmassa-indeks (LMI) is gebruik om tussen oorgewig en obees te onderskei. Elke deelnemer het ‘n ACTICAL™ monitor gedra om hul fisieke-aktiwiteitsvlakke en TEV te bepaal. Die studie het getoon dat die TEV van die kinders op ’n weeksdag en naweekdag nie verskil het nie, alhoewel TEV tydens die middag van die weeksdag betekenisvol verskil het van die oggend s’n. Anders as die oorgewig kinders, het geen van die obese kinders aan die voorgestelde riglyn van 60 minute se matig intensiewe fisieke aktiwiteit per dag voldoen nie. Strategieë moet gevind word om die vlakke van aktiwiteit van oorgewig en veral obese kinders te verhoog, spesifiek gedurende die oggende en oor naweke.

Assessment of habitual physical activity and energy expenditure in dialysis patients and relationships to nutritional parameters

Assessment of physical activity level and of energy expenditure is important in the clinical and nutritional care of dialysis patients, but it is not so easy to accomplish. The SenseWear™ Armband (SWA) is a novel multisensory device that is worn on the upper arm and collects a variety of physiologic data related to physical activity. Thus, duration and intensity of physical activity is recorded and expressed as METs (Metabolic Equivalent Task), and energy expenditure is estimated. The aim of our study was to assess interdialytic spontaneous physical activity in stable chronic hemodialysis (HD) patients and the relation to nutritional status and dietary nutrient intake. In 50 stable patients on maintenance hemodialysis treatment and 33 normal subjects (control group), level of spontaneous physical activity and estimated daily energy expenditure was assessed by SWA and related to biochemistry and anthropometry data, bioelectric impedance vector analysis, and energy and nutrient intake information coming from a 3-day food recall. In respect to controls, HD patients showed lower mean daily METs value (1.3 ± 0.3 vs. 1.5 ± 0.2, p < 0.01), a lower time spent on activities > 3 METs (89 ± 85 vs. 143 ± 104 min/day, p < 0.05), lower number of steps per day (5,584 ± 3,734 vs. 11,735 ± 5,130, p < 0.001), resulting in a lower estimated energy expenditure (2,190 ± 629 vs. 2,462 ± 443 Kcal/day, p < 0.05). 31 out of the 50 HD patients (62%) had a mean daily value < 1.4 METs and hence were defined as sedentary. They differed from the active patients for higher age (63 ± 12 vs. 54 ± 12 y, p < 0.01), lower energy intake (26.1 ± 6.4 vs. 32.4 ± 11.3 Kcal/day, p < 0.05) and lower phase angle (5.5 ± 1.0 vs. 6.3 ± 0.9, p < 0.05). SWA-based estimation of daily energy expenditure was negatively related to age (r = -0.31, p < 0.05), whereas positive relations were observed with BMI (r = 0.51, p < 0.001), phase angle (r = 0.40, p < 0.01), serum phosphate (r = 0.49, p < 0.001) and albumin (r = 0.41, p < 0.01). The mean daily METs values were strongly related to normalized energy intake (r = 0.47, p < 0.001) and also to protein intake (r = 0.33, p < 0.05) and to phase angle (r = 0.38, p < 0.01). Multiple regression analysis showed that energy intake and dietary protein intake were independently related to the intensity of physical activity. Our findings indicate that poor physical activity is highly prevalent in stable dialysis patients even when free from physical or neurological disabilities or severe comorbid conditions. The level and intensity of physical activity is positively related to body composition and to dietary nutrient intake. This confirms the strong interrelationship between exercise and nutrition, which in turn are associated with survival, rehabilitation and quality of life in dialysis patients.

Accuracy of a novel multi-sensor board for measuring physical activity and energy expenditure

The ability to relate physical activity to health depends on accurate measurement. Yet, none of the available methods are fully satisfactory due to several factors. This study examined the accuracy of a multi-sensor board (MSB) that infers activity types (sitting, standing, walking, stair climbing, and running) and estimates energy expenditure in 57 adults (32 females) 39.2 ± 13.5 years. In the laboratory, subjects walked and ran on a treadmill over a select range of speeds and grades for 3 min each (six stages in random order) while connected to a stationary calorimeter, preceded and followed by brief sitting and standing. On a different day, subjects completed scripted activities in the field connected to a portable calorimeter. The MSB was attached to a strap at the right hip. Subjects repeated one condition (randomly selected) on the third day. Accuracy of inferred activities compared with recorded activities (correctly identified activities/total activities × 100) was 97 and 84% in the laboratory and field, respectively. Absolute accuracy of energy expenditure [100 - absolute value (kilocalories MSB - kilocalories calorimeter/kilocalories calorimeter) × 100] was 89 and 76% in the laboratory and field, the later being different (P < 0.05) from the calorimeter. Test-retest reliability for energy expenditure was significant in both settings (P < 0.0001; r = 0.97). In general, the MSB provides accurate measures of activity type in laboratory and field settings and energy expenditure during treadmill walking and running although the device underestimates energy expenditure in the field.

Physical capacity, respiratory quotient and energy expenditure during exercise in male patients with schizophrenia compared with healthy controls

BackgroundDespite massive research on weight gain and metabolic complications in schizophrenia there are few studies on energy expenditure and no current data on physical capacity. AimTo determine oxygen uptake capacity, respiratory quotient (RQ) and energy expenditure during a submaximal exercise test in patients with schizophrenia and healthy controls. MethodTen male patients and 10 controls were included. RQ and energy expenditure were investigated with indirect calorimetry during a cycle ergometer test. The submaximal work level was defined by heart rate and perceived exhaustion. Physical capacity was determined from predicted maximal oxygen uptake capacity (VO2-max). ResultsThe patients exhibited significantly higher RQ on submaximal workloads and lower physical capacity. A significant lower calculated VO2-max remained after correction for body weight and fat free mass (FFM). Energy expenditure did not differ on fixed workloads. ConclusionRQ was rapidly increasing in the patients during exercise indicating a faster transition to carbohydrate oxidation and anaerobic metabolism that also implies a performance closer to maximal oxygen uptake even at submaximal loads. This may restrict the capacity for everyday activity and exercise and thus contribute to the risk for weight gain. Physical capacity was consequently significantly lower in the patients.

Effects of a high-intensity task-oriented training on gait performance early after stroke: a pilot study

Objective: To investigate the feasibility and the effects on gait of a high intensity task-oriented training, incorporating a high cardiovascular workload and large number of repetitions, in patients with subacute stroke, when compared to a low intensity physiotherapy-programme. Design and subjects: Randomized controlled clinical trial: Forty-four patients with stroke were recruited at 2 to 8 weeks after stroke onset. Measures: Maximal gait speed assessed with the 10-metre timed walking test (10MTWT), walking capacity assessed with the six-minute walk test (6MWT). Control of standing balance assessed with the Berg Balance Scale and the Functional Reach test. Group differences were analysed using a Mann—Whitney U-test. Results: Between-group analysis showed a statistically significant difference in favour of the high intensity task-oriented training in performance on the 10MTWT (Z = -2.13, P = 0.03) and the 6MWT (Z = -2.26, P = 0.02). No between-group difference were found for the Berg Balance Scale (Z = —0.07, P = 0.45) and the Functional Reach test (Z = —0.21, P = 0.84). Conclusion: A high-intensity task-oriented training programme designed to improve hemiplegic gait and physical fitness was feasible in the present study and the effectiveness exceeds a low intensity physiotherapy-programme in terms of gait speed and walking capacity in patients with subacute stroke. In a future study, it seems appropriate to additionally use measures to evaluate physical fitness and energy expenditure while walking.

Adipose triglyceride lipase plays a key role in the supply of the working muscle with fatty acids

FAs are mobilized from triglyceride (TG) stores during exercise to supply the working muscle with energy. Mice deficient for adipose triglyceride lipase (ATGL-ko) exhibit defective lipolysis and accumulate TG in adipose tissue and muscle, suggesting that ATGL deficiency affects energy availability and substrate utilization in working muscle. In this study, we investigated the effect of moderate treadmill exercise on blood energy metabolites and liver glycogen stores in mice lacking ATGL. Because ATGL-ko mice exhibit massive accumulation of TG in the heart and cardiomyopathy, we also investigated a mouse model lacking ATGL in all tissues except cardiac muscle (ATGL-ko/CM). In contrast to ATGL-ko mice, these mice did not accumulate TG in the heart and had normal life expectancy. Exercise experiments revealed that ATGL-ko and ATGL-ko/CM mice are unable to increase circulating FA levels during exercise. The reduced availability of FA for energy conversion led to rapid depletion of liver glycogen stores and hypoglycemia. Together, our studies suggest that ATGL-ko mice cannot adjust circulating FA levels to the increased energy requirements of the working muscle, resulting in an increased use of carbohydrates for energy conversion. Thus, ATGL activity is required for proper energy supply of the skeletal muscle during exercise.

Physical activity and energy expenditure measurements using accelerometers in older adults.

The purpose of this review is to address methodological issues related to accelerometer-based assessments of physical activity (PA) in older individuals. Special interest is also put on recently updated technology. No definitive evidence exists currently to indicate which are the more valid and reliable accelerometer models for use with older people. When it comes to selecting an accelerometer, issues of affordability, product reliability, monitor size, technical support, and comparability with other studies may be equally as important as the relative validity and reliability of an instrument. The accelerometer should be attached as close as possible to the body's center of mass, and in the case of elders using walking aids, it should be placed on the same body side. Variability due to positioning can be reduced with careful training and supervision. Typically, the sampling period is between 3 and 7 days and it is not yet clear if variability exists between weekdays and weekend in the elderly. It is possible that aging effects on physical and cognitive health may limit the ability of an older adult to be compliant with an accelerometer protocol; in this line many methods have been suggested for increasing compliance to protocols for research studies. Accelerometers can provide reliable information on mobility and objective measurement of PA. These activity monitors have significant advantages when compared with other quantitative methods for measurement of energy expenditure. Accelerometers are currently used mainly in a research setting; however, with recent advances, incorporation into clinical and fitness practice is possible and increasing.

A rapidly occurring compensatory decrease in physical activity counteracts diet-induced weight loss in female monkeys

To study changes in energy balance occurring during the initial phases of dieting, 18 adult ovariectomized female monkeys were placed on a low-fat diet, and available calories were reduced by 30% compared with baseline consumption for 1 mo. Surprisingly, there was not significant weight loss; however, daily activity level (measured by accelerometry) decreased soon after diet initiation and reached statistical significance by the 4th wk of dieting (18 +/- 5.6% decrease, P = 0.02). During a 2nd mo of dieting, available calories were reduced by 60% compared with baseline consumption, leading to 6.4 +/- 1.7% weight loss and further suppression of activity. Metabolic rate decreased by 68 +/- 12 kcal/day, with decreased activity accounting for 41 +/- 9 kcal/day, and the metabolic activity of the weight lost accounting for 21 +/- 5 kcal/day. A second group of three monkeys was trained to run on a treadmill for 1 h/day, 5 days/wk, at 80% maximal capacity, leading to increased calorie expenditure of 69.6 +/- 10.7 kcal/day (equivalent to 49 kcal/day for 7 days). We conclude that a diet-induced decrease in physical activity is the primary mechanism the body uses to defend against diet-induced weight loss, and undertaking a level of exercise that is recommended to counteract weight gain and promote weight loss is able to prevent the compensatory decrease in physical activity-associated energy expenditure that slows diet-induced weight loss.

Physical activity levels and estimated energy expenditure in overweight and normal‐weight 11‐year‐old children

To objectively evaluate physical activity and energy expenditure in overweight and normal-weight 11-year-old children. The final sample consisted of 91 children (32 overweight and 59 normal-weight children), mean age (SD) = 11.3 (0.2) years. Energy expenditure and physical activity were assessed during two weekdays and two weekend days using a multiple-sensor body monitor (SenseWear Armband; BodyMedia Inc., Pittsburgh, PA, USA). Time spent in physical activity was higher in normal-weight compared with overweight children (p = 0.002). The highest level of physical activity was noted in normal-weight boys [mean (SD) = 258 (114) min/day] and the lowest in overweight girls [mean (SD) = 136 (59) min/day] (p = 0.002). In contrast, energy expended during physical activity did not differ between normal-weight and overweight children (2.6 and 2.7 MJ/day, respectively, p = 0.89). The average decrease in physical activity at weekends was 39 min in overweight children (from 166 to 127 min/day) and 27 min in their normal-weight counterparts (from 230 to 203 min/day). Overweight children engaged in less physical activity of both moderate and vigorous intensity compared with their normal-weight peers. Both overweight and normal-weight children were less active at weekends than on weekdays. Initiatives aiming to increase physical activity of overweight children at weekends are warranted.

Physical activity monitoring in obese people in the real life environment

BackgroundObesity is a major problem especially in western countries and several studies underline the importance of physical activity to enhance diet. Currently there is increasing interest in instruments for monitoring daily physical activity. The purpose of this pilot study was to appraise the qualitative and quantitative differences in physical activities and gait analysis parameters in control and obese subjects by means of an innovative tool for the monitoring of physical activity.MethodsTwenty-six obese patients, 16 women and 10 men, aged 22 to 69 years with Body Mass Index (BMI) between 30 and 51.4 kg/m2, were compared with 15 control subjects, 4 men and 11 women, aged 24 to 69 with BMI between 18 and 25 kg/m2 during daily physical activities. The IDEEA device (Minisun, Fresno, CA), based on a wearable system of biaxial accelerometers and able to continuously record the physical activities and energy expenditure of a subject in time was used. Time spent in different physical activities such as standing, sitting, walking, lying, reclining, stepping, energy expenditure and gait parameters (velocity, stance duration, etc) were measured during a 24-hours period.ResultsA trend toward a reduced number of steps was present, associated to reduced speed, reduced cadence and reduced rate of single and double limb support (SLS/DLS). Moreover, obese people spent significant less time stepping, less time lying and more time in a sitting or reclined position during the night. The energy expenditure during a 24-hours period was higher in the obese compared to controls.ConclusionsThe study provided objective parameters to differentiate the daily motor activity of obese subjects with respect to controls, even a larger population is required to confirm these findings. The device used can be of support in programming educational activities for life style modification in obese people as well as for monitoring the results of various kinds of intervention in these patients concerning weight and physical performance.

Sex Differences in Insulin Dose and Postprandial Glucose as BMI Increases in Patients With Type 2 Diabetes

In a recent review by Geer and Shen (1), using the PubMed database and the references cited in these reports, men were reported to have more lean mass and women to have higher adiposity. Men were also found to have more visceral and hepatic adipose tissue, whereas women had more peripheral or subcutaneous adipose tissue. The researchers concluded that these differences, as well as differences in sex hormones and adipokines, may contribute to a more insulin-sensitive environment in women than in men. When they normalized to kilograms of lean body mass, men and women had similar resting energy expenditure, but physical energy expenditure was more closely related to percent body fat in men than in women. Greater amounts of visceral and hepatic adipose tissue, in conjunction with the …

Physical Activity Levels After Functional Resistance Training Program In Subjects With Low-back Pain

People with chronic low-back pain usually have functional disability due to pain. This conditions and facts could negatively affect the levels of physical activity and energy expenditure from daily life. PURPOSE: To identify changes in levels of physical activity and energy expenditure in daily life produced by a physical activity therapy which integrates functional resistance training. METHODS: Patients with chronic low back pain for more than 8 weeks but less than 6 months were included in the sample. A total of 19 (35,63±8,44 years old) women were randomized to either exercise group (n = 11) or control group (n = 8). 36 exercise sessions were developed in 3 months of intervention. Pain intensity (visual analogue scale 0-10), level of physical activity and energy expenditure (International Physical Activity Questionnaire (IPAQ)) were recorded before and immediately after the treatment period. RESULTS: The control group showed no significant changes after the exercise intervention. In the experimental group the pain intensity had been reduced significantly (p<0,001), increased (p<0,05) 1,36 d·wk-1 the frequency, 149,1 min·wk-1 the duration and 2218,18 METs·min·wk-1 energy expenditure from vigorous physical activities (8 METs). In moderate activities (4 METs) increased (p<0,05) the duration in 59,09 min·wk-1 and weekly reduced the time that remained seated 166,36 min (p<0,05). The total weekly energy expenditure increased 2218,85 METs·min·wk-1 (p<0,05). CONCLUSIONS: Physical activity therapy, including functional resistance training, has produced significant increases in the frequency, duration and energy expenditure from daily life activities and has reduced the daily time that these patients remained seated.

Maturity‐related differences in physical activity among 10‐ to 12‐year‐old girls

Besides environmental and psycho-social factors explaining the variation in physical activity levels during adolescence, some evidence suggests that biological processes are involved in regulating habitual daily physical activity and energy expenditure. The purpose of this study was to examine the influence of biological maturity status on physical activity. Chronological age, standing height, sitting height, and body mass were measured cross-sectionally in 268 girls, aged 9.5 to 11.5 years. Biological maturity groups (Early, Average, Late) were created according to estimated age at peak-height-velocity (estAPHV). Habitual physical activity was determined with a pedometer (Yamax Digiwalker SW-200) over a 7-day period. Differences in steps/day across maturity groups were examined by ANCOVA, controlling separately for time the pedometer was worn, leg length, and body mass. Mean pedometer steps/day was 10,822 +/- 2,639. As expected, body size varied by maturity status (e.g., early > average > late). Significant maturity group differences were found with early maturing girls showing lower activity levels compared to average or late maturers. These differences remained after controlling for time the pedometer was worn and leg length; however, the differences were no longer significant when controlling for body mass. The results suggest that biological maturity status influences physical activity levels in girls between 10 and 12 years of age but the relationship is not independent of body mass. Further research is needed to establish the complex inter-relationships among adiposity, biological maturation, and energy expenditure during puberty.

Physical activity assessment and health outcomes in old age: how valid are dose–response relationships in epidemiologic studies?

Abstract In this systematic review the validity of the dose–response relationships between physical activity (PA) and energy expenditure (EE) on defined health outcomes (cardio- and cerebrovascular morbidity and mortality, cancer) for the elderly is questioned. Medline, Cochrane, and EMBASE databases were reviewed for epidemiological longitudinal studies in populations aged 60+ for the years 1985–2007. Although most of the 18 identified studies generally demonstrated an inverse dose–response relationship between PA and EE level with morbidity and mortality, the range of dose–responses was remarkably broad. The nature of the dose–response relationship remained unclear. PA questionnaires - even those constructed for the elderly - do not cover the extremely diverse aspects of age-specific PA behavior and modes of muscular activity. Only non-age-specific tables had been used to estimate the EE in the elderly. Direct measurements of EE were limited. The results have implications for the interpretation of the dose–response relationships between PA and EE on defined health outcomes in old age.

Is it possible to assess free-living physical activity and energy expenditure in young people by self-report?

Background: It is unclear whether it is possible to accurately estimate physical activity energy expenditure (PAEE) by self-report in youth.Objective: We assessed the validity and reliability of 4 self-reports to assess PAEE and time spent at moderate and vigorous intensity physical activity (MVPA) over the previous week in British young people between 4 and 17 y of age.Design: PAEE and MVPA were derived from the Children’s Physical Activity Questionnaire, Youth Physical Activity Questionnaire, and Swedish Adolescent Physical Activity Questionnaire; a lifestyle score indicative of habitual activity was derived from the Child Heart and Health Study in England Questionnaire. These data were compared with criterion methods, PAEE, and MVPA derived from simultaneous measurements by doubly labeled water and accelerometry in 3 age groups: 4–5 y (n = 27), 12–13 y (n = 25), and 16–17 y (n = 24). Validity was assessed by using Spearman correlations and the Bland-Altman method, and reliability was assessed by using intraclass correlation coefficients.Results: The strength of association between questionnaire and criterion methods varied (r = 0.09 to r = 0.46). Some questionnaires were able to accurately assess group-level PAEE and MVPA for some age groups, but the error was large for individual-level estimates throughout. Reliability of the Youth Physical Activity Questionnaire and Child Heart and Health Study in England Questionnaire was good (intraclass correlation coefficient: 0.64–0.92).Conclusions: Absolute PAEE and MVPA estimated from these self-reports were not valid on an individual level in young people, although some questionnaires appeared to rank individuals accurately. Age (the outcome of interest) and whether individual or group-level estimates are necessary will influence the best choice of self-report method when assessing physical activity in youth.

Gender differences in insulin resistance, body composition, and energy balance

Men and women differ substantially in regard to degrees of insulin resistance, body composition, and energy balance. Adipose tissue distribution, in particular the presence of elevated visceral and hepatic adiposity, plays a central role in the development of insulin resistance and obesity-related complications. This review summarizes published data on gender differences in insulin resistance, body composition, and energy balance, to provide insight into novel gender-specific avenues of research as well as gender-tailored treatments of insulin resistance, visceral adiposity, and obesity. English-language articles were identified from searches of the PubMed database through November 2008, and by reviewing the references cited in these reports. Searches included combinations of the following terms: gender, sex, insulin resistance, body composition, energy balance, and hepatic adipose tissue. For a given body mass index, men were reported to have more lean mass, women to have higher adiposity. Men were also found to have more visceral and hepatic adipose tissue, whereas women had more peripheral or subcutaneous adipose tissue. These differences, as well as differences in sex hormones and adipokines, may contribute to a more insulin-sensitive environment in women than in men. When normalized to kilograms of lean body mass, men and women had similar resting energy expenditure, but physical energy expenditure was more closely related to percent body fat in men than in women. Greater amounts of visceral and hepatic adipose tissue, in conjunction with the lack of a possible protective effect of estrogen, may be related to higher insulin resistance in men compared with women.

5-HT2CRs Expressed by Pro-Opiomelanocortin Neurons Regulate Energy Homeostasis

SummaryDrugs activating 5-hydroxytryptamine 2C receptors (5-HT2CRs) potently suppress appetite, but the underlying mechanisms for these effects are not fully understood. To tackle this issue, we generated mice with global 5-HT2CR deficiency (2C null) and mice with 5-HT2CRs re-expression only in pro-opiomelanocortin (POMC) neurons (2C/POMC mice). We show that 2C null mice predictably developed hyperphagia, hyperactivity, and obesity and showed attenuated responses to anorexigenic 5-HT drugs. Remarkably, all these deficiencies were normalized in 2C/POMC mice. These results demonstrate that 5-HT2CR expression solely in POMC neurons is sufficient to mediate effects of serotoninergic compounds on food intake. The findings also highlight the physiological relevance of the 5-HT2CR-melanocortin circuitry in the long-term regulation of energy balance.

Validation of ActiReg® to measure physical activity and energy expenditure against doubly labelled water in obese persons

ActiReg is an instrument that uses combined recordings of body position and motion to calculate energy expenditure (EE) and physical activity (PA). The aim of the study was to compare mean total energy expenditure (TEE) measured by ActiReg and doubly labelled water (DLW) in obese subjects. TEE was measured by the DLW method during a period of 14 d in fifty obese men and women with metabolic risk factors. During the same period ActiReg recordings were obtained for 7 d. RMR was measured by indirect calorimetry and also estimated by standardized equations. Because EE may be disproportionately increased in obese subjects during weight-bearing activities, we established a new set of physical activity ratios (PAR). These ratios were based on oxygen uptake measurements during treadmill walking. The mean TEE according to the DLW was 13.94 (sd 2.47) MJ/d. Mean TEE calculated from the ActiReg data and measured RMR was 13.39 (sd 2.26) MJ/d, an underestimation of 0.55 MJ (95 % CI 0.13, 0.98; P = 0.012) or 3.9 %. RMR derived from standard equations based on weight, age and sex were overestimated while the RMR based on fat-free mass values in addition was underestimated. Despite slight underestimation ActiReg may be used to measure TEE in obese subjects on two premises: RMR should be measured, and the increased EE during weight-bearing activities in obese subjects should be considered.

Accuracy of an Armband Type Physiological Body Monitor to Estimate Light/Sedentary Activities of Daily Living

The increased prevalence of overweight and obesity among adults has prompted health researchers to investigate physical activity behaviors. An objective, accurate instrument to quantitatively assess physical activity and energy expenditure (EE) may enhance the understanding of the current obesity epidemic. PURPOSE: To evaluate the accuracy of an Armband type physiologic body monitor to estimate EE during light/sedentary activities of daily living in adults compared to indirect calorimetry (IC). METHODS: A total of 33 adults [mean (SD) age: 27.5 (9.2) y; height: 169.2 (10.1) cm; body mass: 74.1 (15.0) kg; BMI: 25.7 (3.7) kg/m2] performed 10 minutes each of folding laundry (n = 18), paperwork (n = 29), listening to music (n = 15), computer work (n = 16), quiet reading (n = 11), and watching television (n = 17). The Armband was positioned mid-humerous on the posterior aspect of the right arm. Simultaneous continuous measurements of EE were recorded by the Armband and IC (COSMED, USA) during the activities. Difference scores for activities were calculated as Armband EE minus IC EE, and a one-sample t-test was used to determine if the mean differences were significantly different from zero. RESULTS: For each activity, mean EE recorded by the Armband was significantly greater than IC EE (P < 0.01). Mean (SEM) difference scores between the Armband and indirect calorimetry were significantly different than zero (P < 0.001) during folding laundry [1.6 (0.1) kcal/min], paperwork [0.7 (0.1) kcal/min], listening to music [0.6 (0.1) kcal/min], computer work [0.5 (0.1) kcal/min], quiet reading [0.5 (0.1) kcal/min], and watching television [0.4 (0.1) kcal/min]. CONCLUSION: Compared to IC, the Armband overestimated the EE of adults during light/sedentary activities of daily living. Considering that the typical adult spends more than 50 awake hours per week engaged in sedentary activities, the armband could overestimate daily EE by more than 215 kcal/day. While the mean difference in the EE of light/sedentary activities between the Armband and IC may appear to be of minimal physiological significance, the summative error over a prolonged measurement interval (free-living) can lead to a gross overestimation of EE and potentially confound an individual's weight management program. Supported by the Paso del Norte Health Foundation.

Validity of a Multisensor Armband in Estimating 24-h Energy Expenditure in Children

Physical activity (PA) and energy expenditure (EE) in children are frequently assessed using portable activity monitors. Algorithms used to predict EE by these monitors are often based on adult populations and may not be accurate for children. To evaluate the accuracy of the SenseWear Pro Armband (SWA) for assessing EE in African American children during treadmill exercise, sedentary activities, rest, sleep, and total 24-h EE, using indirect room calorimetry (IRC) as a reference standard. Participants were healthy African American children (10 boys, 11 girls; age: 11.6 +/- 0.9 yr; weight: 47.3 +/- 13.0 kg; height: 151.6 +/- 8.8 cm; BMI: 20.4 +/- 4.8 kg.m). EE was measured simultaneously using IRC and SWA during a 24-h stay in the IRC. Recorded activities included sedentary behaviors, treadmill exercise, rest periods, and sleep. Results from both methods were matched minute-by-minute and compared by Bland-Altman plot. Multiple linear regression analysis was used to describe the relationship between EE assessed by both methods and children's descriptive characteristics. SWA overestimated EE compared with IRC during all activities and time periods, ranging from 116% during sleep to 143% during rest after treadmill exercise. The SWA-predicted EE was improved by using linear regression modeling. Simple equations for sedentary activities and treadmill exercise were EE [kcal.min] = 0.462EE (SWA) [kcal.min] + 0.015 x body weight [kg], and EE [kcal.min] = 0.637EE (SWA) [kcal.min] + 0.034 x body weight [kg], respectively. The prediction equation for RMR was RMR [kcal.min] = 0.453EE (SWA) [kcal.min] + 0.011 x body weight [kg]. EE estimated using SWA was significantly higher than EE measured using IRC in African American children ages 10-14 yr. Bias in individual EE estimated using SWA could be improved by an adjustment for the body weight of a child. The SWA manufacturer should work with researchers on improving existing algorithms for children.