Ratio Of Total Energy Expenditure Research Articles

ARTE index revisited: linking biomarkers of cardiometabolic health with free-living physical activity in postmenopausal women.

Activity-related energy expenditure (AEE) correlates with physical activity volume; however, between-person differences in body size and walking economy (net V̇o2) can influence AEE. The ratio of total energy expenditure (TEE) and resting energy expenditure (REE) estimates physical activity level (PAL) relative to body mass, yet does not account for variance in walking economy. The activity-related time equivalent (ARTEwalk) circumvents such constraints by adjusting for individual-specific walking economy. Herein, we compared AEE, PAL, and ARTEwalk index in a cohort (n = 81) of postmenopausal women while examining possible associations with biomarkers of cardiometabolic health. Secondary analyses were performed on postmenopausal women dichotomized above/below age group 50th percentile for body fat percent. TEE was reduced by 10% for the thermogenesis of digestion wherein AEE was calculated by subtracting REE from adjusted TEE. PAL was calculated as the ratio of TEE/REE. AEE was divided by the mean net energy expenditure of nongraded walking to calculate the ARTEwalk index. Between-group differences were not detected for AEE or PAL. However, the ARTEwalk index revealed that participants with less adiposity were more physically active (258 ± 149 vs. 198 ± 115 min·day-1; P = 0.046; g = 0.46). AEE and PAL did not correlate with cardiorespiratory fitness or biomarkers of cardiometabolic health. Cardiorespiratory fitness (r = 0.32), arterial elasticity (r = 0.24), total cholesterol/HDL-c ratio (r = -0.22), and body fat% (r = -0.24) were correlated with ARTEwalk. The ARTEwalk index may offer utility in detecting possible differences in physical activity volume among postmenopausal women and appears better associated with cardiometabolic biomarkers compared with AEE or PAL.

Association between energy intake under‐reporting and previous professional nutritional counselling in low‐income women with obesity: A cross‐sectional study

AbstractIt is unclear if individuals who have previously been counselled by nutrition professionals are more prone to subsequently under‐report their energy intake. This study aimed to determine whether there is an association between energy intake under‐reporting and previous professional nutritional counselling for weight control in low‐income women with obesity. This is a cross‐sectional study. Adult women (19–44 years old in Brazil) with obesity, living in a household classified as the lowest economic strata, were included. Energy intake (EI) was identified using 24‐h food records (for three non‐consecutive days, including a weekend day. Total energy expenditure (TEE) was assessed using indirect calorimetry and triaxial accelerometers. Individuals with EI:TEE ratio below 0.65 were considered as under‐reporters. Participants were also asked if they had been previously counselled by a nutrition professional for their obesity treatment. Association was calculated using a multivariable model, adjusted for age, bodyweight, height, education and body fat. The sample consisted of 58 women, with a mean age of 33 years and a body mass index of 32.51 kg/m2. Among total participants, 20 (34.5%) women had undergone previous professional nutritional counselling, and 21 (36.2%) under‐reported their EI. Women who had already had some counselling with a nutrition professional had a higher adjusted prevalence of under‐reporting their EI [adjusted prevalence ratio: 2.58; 95% CI (1.27; 5.25), p = 0.008]. Low‐income women with obesity who had undergone previous professional nutritional counselling for weight loss showed a higher prevalence of under‐reporting their EI.

Factors Associated With Energy Expenditure and Energy Balance in Acute Sport-Related Concussion.

Sport-related concussion (SRC) is characterized by a pathologic neurometabolic cascade that results in an increased intracranial energy demand and a decreased energy supply. Little is known about the whole-body energy-related effects of SRC. To examine factors associated with whole-body resting metabolic rate (RMR), total energy expenditure (TEE), energy consumption (EC), and energy balance (EBal) in student-athletes acutely after SRC and healthy matched control individuals. Case-control study. University research laboratory. Student-athletes diagnosed with SRC (n = 28, 50% female, age = 18.4 ± 1.8 years, body mass index [BMI] = 24.1 ± 4.1 kg/m2) assessed ≤72 hours postinjury and a matched control group (n = 28, 50% female, age = 19.4 ± 2.9 years, BMI = 24.7 ± 4.78 kg/m2). Resting metabolic rate was measured via indirect calorimetry. Participants reported their physical activity and dietary intake for 3 days, which we used to estimate TEE and EC, respectively, and to calculate EBal (EC:TEE ratio). Resting metabolic rate, TEE, and EC were normalized to body mass. Group and group-by-sex comparisons were conducted for RMR·kg-1, TEE·kg-1, EC·kg-1, and EBal using independent t tests with the a priori α = .05. Associations of age, sex, concussion history, BMI, and symptom burden with RMR·kg-1 and EBal were explored with linear regression models. Total energy expenditure·kg-1 was lower (P < .01; mean difference ± SD = -5.31 ± 1.41 kcal·kg-1) and EBal was higher (P < .01; 0.28 ± 0.10) in SRC participants than in control participants. Both sexes with SRC had lower TEE·kg-1 than did the control participants (P values ≤ .04); females with SRC had higher EBal than controls (P = .01), but male groups did not differ. Higher RMR·kg-1 was associated with history of concussion (adjusted R2 = .10, β = 0.65). Younger age (β = -0.35), fewer concussions (β = -0.35), lower BMI (β = -0.32), greater symptom duration (β = 1.50), and lower symptom severity (β = -1.59) were associated with higher EBal (adjusted R2 = .54). Total energy expenditure·kg-1 and EBal appeared to be affected by acute SRC, despite no differences in RMR·kg-1. Sex, concussion history, BMI, and symptom burden were associated with acute energy-related outcomes.

The ARTE index: Characterizing free‐living physical activity and indices of cardio‐metabolic health among postmenopausal women

PurposeThe doubly‐labeled water (DLW) technique is the gold‐standard used to objectively measure free‐living activity energy expenditure (AEE), however; it does not account for differences in body size or locomotion economy. Whereas the physical activity level (PAL) index, calculated from the ratio of total energy expenditure (TEE) and resting energy expenditure (REE), is employed to adjust for body size – it also does not account for variance in energy expenditure attributed to locomotion economy. Alternatively, the activity‐related time equivalent (ARTE) circumvents the limitations of AEE and PAL. In the present work, DLW was used to compare AEE, PAL, and variations of the ARTE index among a cohort of postmenopausal women dichotomized above/below the 50th percentile of normative data for body fat%. Correlations of AEE, PAL, and ARTE to measures of cardio‐metabolic health including arterial elasticity, body fat% and cardiorespiratory fitness (V̇O2max) were also performed.MethodsNinety‐two, healthy postmenopausal women (65+/−4 years) were recruited to measure free‐living AEE over a 14‐day period using DLW. TEE was reduced by 10% to account for the thermogenesis of feeding whereas AEE was calculated by subtracting REE from adjusted‐TEE. PAL was calculated from the ratio of TEE/REE. ARTE4act was calculated by dividing AEE by the average energy expenditure of non‐graded walking, graded walking, stair climbing, and a carrying task. AEE divided by the average energy expenditure of non‐graded walking was used to calculate ARTEwalk. Arterial elasticity was performed using pulse contour analysis from the radial artery. Dual‐energy X‐ray absorptiometry was used to estimate body fat% whereas a modified‐Balke protocol was used to measure V̇O2max. Between‐group comparisons were performed using independent t‐tests and Pearson’s correlation were used to evaluate relationships.ResultsBetween‐group differences were not detected for AEE, PAL, or the ARTE4act. However, women with less percent body fat (i.e., &lt; 50th percentile) exhibited greater activity as evidenced by the ARTEwalk (min·day−1) (255+/−154 vs. 193+/−130; p &lt; 0.05). Though AEE and PAL did not correlate with any cardio‐metabolic variables, ARTE4act was related to arterial elasticity (r = 0.24) and V̇O2max (r = 0.27) while ARTEwalk was related to arterial elasticity (r = 0.27), body fat% (r = −0.24), and V̇O2max (r = 0.32).ConclusionsConsistent with the ARTEwalk, adjustments for energetic cost of non‐graded walking may improve the sensitivity of AEE for detecting differences in free‐living physical activity and parameters of cardio‐metabolic health – known to be critical for overall well‐being.Support or Funding InformationThis investigation was supported by the following grants from the National Institutes of Health: R01AG027084‐01, R01AG027084‐S, P30DK056336, P60DK079626, and UL1RR025777.

Total energy expenditure in patients with colorectal cancer: associations with body composition, physical activity, and energy recommendations

Total energy expenditure (TEE) data in patients with early-stage cancer are scarce, precluding an understanding of energy requirements. The objective was to cross-sectionally characterize TEE in patients with colorectal cancer (CRC) and to compare measured TEE with energy recommendations. It was hypothesized that TEE would differ according to body mass, body composition, and physical activity level (PAL) and current energy recommendations would have poor individual-level accuracy. Patients with newly diagnosed CRC had resting energy expenditure (REE) measured by indirect calorimetry and TEE by doubly labeled water. Hypermetabolism was defined as REE>110% of that predicted from the Mifflin St.-Jeor equation. Body composition was assessed via DXA. Physical activity was determined as the ratio of TEE to REE (TEE:REE) (PAL) and residual activity energy expenditure (RAEE). TEE was compared with energy recommendations of 25-30 kcal/d and Dietary Reference Intakes (DRIs) using Bland-Altman analyses. Patients were stratified according to median BMI, PAL, and sex-specific ratio of fat mass (FM) to fat-free mass (FFM). Twenty-one patients (M:F 14:7; mean±SD BMI: 28.3±4.9 kg/m2, age: 57±12 y) were included. Most (n=20) had stage II-III disease; 1 had stage IV. Approximately half (n=11) were hypermetabolic; TEE was not different in those with hypermetabolism and REE as a percentage of predicted was not correlated with TEE. Mean±SD TEE was 2473±499 kcal/d (range: 1562-3622 kcal/d), or 29.7±6.3 kcal/kg body weight (range: 20.4-48.5 kcal/kg body weight). Mean±SD PAL was 1.43±0.27. The energy recommendation of 25 kcal/kg underestimated TEE (-12.6%±16.5%, P=0.002); all energy recommendations had wide limits of agreement (the smallest was DRI with measured PAL: -21.2% to 29.3%). Patients with higher BMI and FM:FFM had higher bias using kilocalories per kilogram recommendations; bias from several recommendations was frequently lower (i.e. underestimation) in patients with higher PAL and RAEE. TEE variability was not reflected in energy recommendations and error was related to body weight, body composition, and physical activity. This trial was registered at clinicaltrials.gov as NCT03131921.

Total energy expenditure assessed by doubly labeled water technique and estimates of physical activity in Mauritian children: analysis by gender and ethnicity

Background/objectivesIn the tropical island of Mauritius, the rise in obesity has accelerated in the past decades, and could be contributed by low physical activity and increased sedentary behavior. The study objectives were to generate the first dataset of total energy expenditure (TEE), to estimate physical activity in Mauritian children, and to explore differences due to gender and ethnicity.Subjects/methodsThe doubly labeled water (DLW) technique was used to evaluate TEE over 14 days in 56 Mauritian school children (aged 7–11 years) belonging to the two main ethnic groups: Indian (South Asian descent) and Creole (African/Malagasy descent). Physical activity level (PAL) was calculated as the ratio of TEE and resting energy expenditure (using Schofield equations), and daily step counts were measured by accelerometry. Anthropometry and body composition were also assessed.ResultsTEE measured by DLW was lower in Mauritian children (by ~155 kcal/d) than that predicted using FAO/WHO/UNU equations for children of the same sex, age, and body size. Furthermore, TEE, as well as PAL and step counts, also differed according to gender (lower in girls than in boys) and to ethnicity (lower in Indians than in Creoles) even after adjusting for differences in body weight and body composition.ConclusionThese results in Mauritian children provide the first dataset of objectively measured TEE, from which physical activity is estimated as PAL, and complemented by step counts measurements. They suggest potential gender and ethnic differences in TEE and physical activity that need consideration in developing strategies to counter sedentary behavior and obesity.

Self-Reported Interview-Assisted Diet Records Underreport Energy Intake in Maintenance Hemodialysis Patients

Studies suggest that maintenance hemodialysis (MHD) patients report dietary energy intakes (EIs) that are lower than what is actually ingested. Data supporting this conclusion have several important limitations. The present study introduces a novel approach of assessing underreporting of EI in MHD patients. Comparisons of EI of free-living MHD patients determined from food records to their measured energy needs. Metabolic research ward. Thirteen clinically stable MHD patients with unchanging weights whose EI was assessed by dietitian interview-assisted 3-day food records. EI was compared with (1) patients' resting energy expenditure (REE), measured by indirect calorimetry, and estimated total energy expenditure (TEE) and (2) patients' dietary energy requirements (DER) measured while patients underwent nitrogen balance studies and consumed a constant energy diet in a research ward for a mean duration of 89.5 days. DER was calculated as the actual EI during the research study corrected for changes in body fat and lean body mass measured by Dual X-Ray Absorptiometry. Underreporting of EI was determined by an EI:REE ratio <1.27 and an EI:TEE ratio or EI:DEE ratio <1.0. Seven of the 13 MHD patients studied were male. Patient's ages were 47.7 ± standard deviation 9.7 years; body mass index averaged 25.4 ± 2.8 kg/m2, and dialysis vintage was 53.3 ± 37.1 months. The EI:REE ratio (1.03 ± 0.23) was significantly less than the cutoff value for underreporting of 1.27 (P = .001); 12 of 13 patients had EI:REE ratios <1.27. The mean EI:TEE ratio was significantly less than the cutoff value of 1.0 (0.73 ± 0.17, P < .0001), and 12 MHD patients had EI:TEE ratios <1.0. The EI:DER ratio was also <1.0 (0.83 ± 0.25, P = .012), and 10 MHD had EI:DER ratios <1.0. Dietitian interview-assisted diet records by MHD patients substantially underestimate the patient's dietary EI.

A Measurement Error Model for Physical Activity Level as Measured by a Questionnaire With Application to the 1999-2006 NHANES Questionnaire

Systematic investigations into the structure of measurement error of physical activity questionnaires are lacking. We propose a measurement error model for a physical activity questionnaire that uses physical activity level (the ratio of total energy expenditure to basal energy expenditure) to relate questionnaire-based reports of physical activity level to true physical activity levels. The 1999-2006 National Health and Nutrition Examination Survey physical activity questionnaire was administered to 433 participants aged 40-69 years in the Observing Protein and Energy Nutrition (OPEN) Study (Maryland, 1999-2000). Valid estimates of participants' total energy expenditure were also available from doubly labeled water, and basal energy expenditure was estimated from an equation; the ratio of those measures estimated true physical activity level ("truth"). We present a measurement error model that accommodates the mixture of errors that arise from assuming a classical measurement error model for doubly labeled water and a Berkson error model for the equation used to estimate basal energy expenditure. The method was then applied to the OPEN Study. Correlations between the questionnaire-based physical activity level and truth were modest (r = 0.32-0.41); attenuation factors (0.43-0.73) indicate that the use of questionnaire-based physical activity level would lead to attenuated estimates of effect size. Results suggest that sample sizes for estimating relationships between physical activity level and disease should be inflated, and that regression calibration can be used to provide measurement error-adjusted estimates of relationships between physical activity and disease.

Physical Activity and Modernization among Bolivian Amerindians

BackgroundPhysical inactivity is a growing public health problem, and the fourth leading risk factor for global mortality. Conversely, indigenous populations living traditional lifestyles reportedly engage in vigorous daily activity that is protective against non-communicable diseases. Here we analyze physical activity patterns among the Tsimane, forager-horticulturalists of Amazonian Bolivia with minimal heart disease and diabetes. We assess age patterns of adult activity among men and women, test whether modernization affects activity levels, and examine whether nascent obesity is associated with reduced activity.Methods and FindingsA factorial method based on a large sample of behavioral observations was employed to estimate effects of age, sex, body mass index, and modernization variables on physical activity ratio (PAR), the ratio of total energy expenditure to basal metabolic rate. Accelerometry combined with heart rate monitoring was compared to the factorial method and used for nighttime sampling. Tsimane men and women display 24 hr physical activity level (PAL) of 2.02–2.15 and 1.73–1.85, respectively. Little time was spent “sedentary”, whereas most activity was light to moderate, rather than vigorous. Activity peaks by the late twenties in men, and declines thereafter, but remains constant among women after the early teens. Neither BMI, fat free mass or body fat percentage are associated with PAR. There was no negative effect of modernization on physical activity.ConclusionsTsimane display relatively high PALs typical of other subsistence populations, but of moderate intensity, and not outside the range of developed populations. Despite rapidly increasing socioeconomic change, there is little evidence that total activity has yet been affected. Overweight and obesity are more prevalent among women than men, and Spanish fluency is associated with greater obesity in women. The lack of cardiovascular disease among Tsimane is unlikely caused by activity alone; further study of diet, food intake and infectious disease is needed.

Physical activity level and its clinical correlates in chronic obstructive pulmonary disease: a cross-sectional study

BackgroundDecreased physical activity is associated with higher mortality in subjects with COPD. The aim of this study was to assess clinical characteristics and physical activity levels (PALs) in subjects with COPD.MethodsSeventy-three subjects with COPD (67 ± 7 yrs, 44 female) with one-second forced expiratory volume percentage (FEV1%) predicted values of 43 ± 16 were included. The ratio of total energy expenditure (TEE) and resting metabolic rate (RMR) was used to define the physical activity level (PAL) (PAL = TEE/RMR). TEE was assessed with an activity monitor (ActiReg), and RMR was measured by indirect calorimetry. Walking speed (measured over 30-meters), maximal quadriceps muscle strength, fat-free mass and systemic inflammation were measured as clinical characteristics. Hierarchical linear regression was applied to investigate the explanatory values of the clinical correlates to PAL.ResultsThe mean PAL was 1.47 ± 0.19, and 92% of subjects were classified as physically very inactive or sedentary. The walking speed was 1.02 ± 0.23 m/s, the quadriceps strength was 31.3 ± 11.2 kg, and the fat-free mass index (FFMI) was 15.7 ± 2.3 kg/m2, identifying 42% of subjects as slow walkers, 21% as muscle-weak and 49% as FFM-depleted. The regression model explained 45.5% (p < 0.001) of the variance in PAL. The FEV1% predicted explained the largest proportion (22.5%), with further improvements in the model from walking speed (10.1%), muscle strength (7.0%) and FFMI (3.0%). Neither age, gender nor systemic inflammation contributed to the model.ConclusionsApart from lung function, walking speed and muscle strength are important correlates of physical activity. Further explorations of the longitudinal effects of the factors characterizing the most inactive subjects are warranted.

Energy expenditure and physical activity of ambulatory children with cerebral palsy and of typically developing children

Children with cerebral palsy (CP) expend more energy when walking than do their typically developing peers. The effect this has on physical activity levels (PALs) and on total energy expenditure (TEE) will have important implications when determining energy requirements. This study aimed to investigate the components of TEE in children with CP in comparison with typically developing children and to determine what effect the higher energy expenditure during walking has in ambulatory children with CP on PAL and on TEE. Sixteen children with mild CP and 16 typically developing children, aged 5-12 y, were recruited for the study. Resting energy expenditure (REE) and the energy expenditure during walking were measured by using indirect calorimetry. TEE was determined by using the doubly labeled water technique. PAL was calculated as the ratio of TEE to REE. Body composition was estimated by using oxygen-18. TEE was lower in children with CP (7012 +/- 1268 kJ/d) than in typically developing children (8309 +/- 2088 kJ/d) because of a lower PAL (1.57 +/- 0.23 compared with 1.79 +/- 0.26). The children with CP expended significantly more energy when walking than did the typically developing children (13.8 +/- 4.9 compared with 10.3 +/- 2.3 kJ/min) while walking at a lower velocity (61 +/- 10 compared with 72 +/- 8 m/min). Correlations between energy expenditure during walking and PAL were not statistically significant for either group. Children with CP expend more energy during walking and have a lower PAL and lower energy requirements than do typically developing children. This has important implications when estimating the energy requirements of children with CP.

Self‐Reported, Interview‐Assisted Diet Records Underreport Protein and Energy Intake in Maintenance Hemodialysis (MHD) Patients

Some studies state that MHD patients underreport energy intake (EI) although energy needs are normal and weight is stable over time. Body mass may not reflect changes in energy stores in MHD patients who cannot regulate water balance normally. Validity of dietary data was evaluated by comparing reported EI with actual dietary EI (aEI) in 13 MHD patients participating in a 93‐day N balance study in a research ward to determine protein needs. Resting energy expenditure (REE) was measured prior to admission to estimate total energy expenditure (TEE) and dietary needs to maintain stable weight. Protein intake was changed ~ every 19 days; aEI was constant throughout the study. Total energy requirements were estimated by aEI corrected for changes in body fat measured by DXA over the 93 day study. Underreporting of EI was determined by a EI:REE ratio &lt;1.27 and EI:TEE ratio&lt;1.0.Age was 47.9±9.7 years; BMI, 25.7 ± 4.7 kg/m2. Self‐reported Intake REE (kcals/d ay) TEE (kcals/d ay) EI: RE E EI: TEE kcals/d ay kcals/kg Protei n (g/kg) 1712±4 98 25.4± 7.4 1.03± 0.3 1676±3 31 2134±3 54 1.0 ± 0.2 0.8±0 .2 Body mass and fat were essentially unchanged (−0.87 kg ± 2.02 kg; 0.74 kg ±1.62 kg) during the study suggesting that pre‐study EI was underreported by ~20%. Variance of reported protein and EI was twice that of aEI. Widespread energy underreporting severely compromises the validity of self‐reported, interview‐assisted diet records in MHD patients.

Validity of the Modified Baecke Questionnaire: comparison with energy expenditure according to the doubly labeled water method

BackgroundIn epidemiological research, physical activity is usually assessed by questionnaires. Questionnaires are suitable for large study populations since they are relatively inexpensive and not very time consuming. However, questionnaire information is by definition subjective and prone to recall bias, especially among elderly subjects. The Modified Baecke Questionnaire, developed by Voorrips and coworkers, measures habitual physical activity in the elderly. The questionnaire includes questions on household activities, sports, and leisure time activities, over a time period of one year. The Modified Baecke Questionnaire results in a score to classify people as high, moderate, or low in daily physical activity, based on tertiles.MethodsThe validity of the Modified Baecke Questionnaire score was assessed among 21 elderly men and women using the doubly labeled water method as the reference criterion. This method is considered to be the gold standard for measuring energy expenditure in free-living individuals. Energy expenditure on physical activity is estimated by the ratio of total energy expenditure measured by the doubly labeled water method and resting metabolic rate measured by indirect calorimetry. This ratio is called the physical activity ratio.ResultsThe Spearman correlation coefficient between the questionnaire score and the physical activity ratio (PAR) was 0.54 (95% CI 0.22–0.66). Correct classification by the questionnaire occurred in 71% of participants who were in the lowest tertile of PAR, in 14% of participants in the middle tertile, and in 43% of participants in the highest tertile. Subjects were not wrongly classified in an opposite tertile.ConclusionThe validity of the Modified Baecke Questionnaire is fair-to-moderate. This study shows that the questionnaire can correctly classify individuals as low or high active, but does a poor job for moderately active individuals.

Comparison Of Habitual Physical Activity Measured By Heart Rate And By Accelerometry In Cerebral Palsy

Physical activity (PA) has physiologic, mechanical and behavioral components. We have previously shown that for children and adolescents with mild spastic cerebral palsy (CP), their habitual PA measured physiologically with monitored heart rate (HR) is related to their physiologic walking economy (oxygen cost of walking). We have also shown for this population that their habitual PA measured mechanically with tri-axial accelerometry is related to their biomechanical walking economy (vertical excursion of the center of mass relative to that expected in normal gait). In both instances, those with the higher levels of PA were the more economical walkers. The relationship between physiologic and mechanical measures of PA in this population, however, is unknown. PURPOSE To determine, in children and adolescents with cerebral palsy (CP), the relationship between; 1) habitual PA as measured by monitored HR and by tri-axial accelerometry and 2) habitual PA and gross motor function related to walking (GMF-W). METHODS Ten subjects (10.6–16.3 yr) with mild spastic CP, simultaneously wore a HR monitor and a tri-axial accelerometer for two weekdays and one weekend day. PAL, the ratio of total energy expenditure to resting energy expenditure, was determined from the monitored HR data, with individual HR-oxygen uptake calibrations and resting measures done in the lab. From the accelerometry data, total vector magnitude movement counts ± d−1 (TMC) and the number of minutes ± d−1 TMC were above the 90th percentile for the group (TMC90) were determined. GMF-W was measured in the lab using the Walking, Running and Jumping Dimension of the Gross Motor Function Measure. Relationships were analyzed using linear regression techniques. Alpha was set at .05. RESULTS PAL (1.33 ± .04) was significantly related (r=.75) to TMC (1.53 ± 105 ± 1.4 ± 104 counts) and (r=.78) to TMC90 (59.8 ± 8.1 minutes). PAL was also significantly related (r=.82) to GMF-W (82.1 ± 5.6%) as were TMC (r=.89) and TMC90 (r=.90). There was no significant relationship for PAL, TMC, TMC90 or GMF-W with age (r=.00001 to .21, P=.60 to 1.0). CONCLUSIONS For older children and adolescents with mild CP, those with higher levels of the physiologic component of PA, may also have higher levels of the mechanical component. Those with higher levels of either component of habitual PA, may also have the better gross motor function related to walking. Further research is needed to determine if, and to what extent, this gross motor function is related to metabolic and mechanical walking economy.

Comparison Of Habitual Physical Activity Measured By Heart Rate And By Accelerometry In Cerebral Palsy

Physical activity (PA) has physiologic, mechanical and behavioral components. We have previously shown that for children and adolescents with mild spastic cerebral palsy (CP), their habitual PA measured physiologically with monitored heart rate (HR) is related to their physiologic walking economy (oxygen cost of walking). We have also shown for this population that their habitual PA measured mechanically with tri-axial accelerometry is related to their biomechanical walking economy (vertical excursion of the center of mass relative to that expected in normal gait). In both instances, those with the higher levels of PA were the more economical walkers. The relationship between physiologic and mechanical measures of PA in this population, however, is unknown. PURPOSE To determine, in children and adolescents with cerebral palsy (CP), the relationship between; 1) habitual PA as measured by monitored HR and by tri-axial accelerometry and 2) habitual PA and gross motor function related to walking (GMF-W). METHODS Ten subjects (10.6–16.3 yr) with mild spastic CP, simultaneously wore a HR monitor and a tri-axial accelerometer for two weekdays and one weekend day. PAL, the ratio of total energy expenditure to resting energy expenditure, was determined from the monitored HR data, with individual HR-oxygen uptake calibrations and resting measures done in the lab. From the accelerometry data, total vector magnitude movement counts ± d−1 (TMC) and the number of minutes ± d−1 TMC were above the 90th percentile for the group (TMC90) were determined. GMF-W was measured in the lab using the Walking, Running and Jumping Dimension of the Gross Motor Function Measure. Relationships were analyzed using linear regression techniques. Alpha was set at .05. RESULTS PAL (1.33 ± .04) was significantly related (r=.75) to TMC (1.53 ± 105 ± 1.4 ± 104 counts) and (r=.78) to TMC90 (59.8 ± 8.1 minutes). PAL was also significantly related (r=.82) to GMF-W (82.1 ± 5.6%) as were TMC (r=.89) and TMC90 (r=.90). There was no significant relationship for PAL, TMC, TMC90 or GMF-W with age (r=.00001 to .21, P=.60 to 1.0). CONCLUSIONS For older children and adolescents with mild CP, those with higher levels of the physiologic component of PA, may also have higher levels of the mechanical component. Those with higher levels of either component of habitual PA, may also have the better gross motor function related to walking. Further research is needed to determine if, and to what extent, this gross motor function is related to metabolic and mechanical walking economy.

Physical Activity Level is Associated with the O2 Cost of Walking in Cerebral Palsy

To determine, in children and adolescents with cerebral palsy (CP), the relationship between physical activity level (PAL) and i) oxygen cost of walking, and ii) peak VO2. In 11 subjects (10.6-16.3 yr) with mild CP, PAL, the ratio of total energy expenditure to resting energy expenditure, was determined from 3 d of heart rate (HR) monitoring (field), with individual HR-VO2 calibrations done in the lab. The oxygen cost of walking was measured during three 3-min walks on a treadmill at 60, 75, and 90% of each subject's fastest treadmill walking speed (FWS). Subjects also performed a maximal treadmill exercise test. Alpha was set at 0.05. One subject was an outlier and eliminated from all simple linear regression analyses. For the remaining 10 subjects, PAL (1.37+/-0.18) was related (r=-0.70 to -0.84) to net VO2 at 60 and 75% FWS (13.1+/-4.1 and 16.2+/-4.2 mL.kg.min), net VO2.m, averaged across the three speeds (0.32+/-0.23 mL.kg.m), and percent peak VO2 at all three speeds (54.5+/-21.5, 63.5+/-20.9, and 75.5+/-15.1%). PAL was not significantly related to net VO2 at 90% FWS (20.8+/-5.3 mL.kg.min) or to peak VO2 (34.0+/-9.2 mL.kg.min). For this population, those with low PAL may also have a high oxygen cost of walking. These individuals' PAL was not related to their peak VO2. Further research is required to determine whether interventions that decrease the oxygen cost of walking also affect PAL and whether changes in PAL affect the oxygen cost of walking.

Water loss as a function of energy intake, physical activity and season

Although water is an important nutrient, there are no recommended intake values. Here, water intake, energy intake, physical activity and water loss was measured over 1 week in summer and in winter. Subjects were healthy volunteers, forty-two women and ten men, mean age of 29 (SD 7) years and mean BMI 21.8 (SD 2.2) kg/m2. Water intake was measured with a 7 d food and water record. Physical activity level (PAL) was observed as the ratio of total energy expenditure, as measured with doubly labelled water, to resting energy expenditure as measured in a respiration chamber. Water loss was measured with the deuterium elimination method. Water loss was highly reproducible and ranged from 0.20 to 0.35 l/MJ, independent of season and activity level, with higher values in women. Water loss was related to water and energy intake in summer (r 0.96, P<0.0001 and r 0.68, P<0.001, respectively) as well as in winter (r 0.98, P<0.0001 and r 0.63, P<0.01, respectively). Water loss was, for men, higher in subjects with a higher physical activity in summer (r 0.94, P<0.0001) and in winter (r 0.70, P<0.05). Normalizing water loss for differences in energy expenditure by expressing water loss in litres per MJ resulted in the same value for men in summer and winter. For women, physical activity-adjusted values of water loss were higher, especially in summer. In men, water turnover was determined by energy intake and physical activity, while seasonal effects appeared through energy expenditure. Women showed a higher water turnover that was unrelated to physical activity.

Energy expenditure in ischemic stroke patients treated with moderate hypothermia.

To determine total energy expenditure (TEE) in patients with acute ischemic stroke in the territory of the middle cerebral artery (MCA), treated with moderate hypothermia (33 degrees C). Prospective study in a neurological ICU. Ten consecutive patients with severe MCA infarction undergoing moderate hypothermia. Indirect calorimetry was performed continuously over the first 6 days after admission. Mean daily TEE decreased significantly from 1549 before initiation of hypothermia to 1099, 1129, and 1157 on the first, second, and third days of hypothermia, respectively and returned to baseline values after hypothermia was terminated. The ratio of TEE to predicted basal energy expenditure declined from 1.01 before induction of hypothermia to an average of 0.74 during steady state of hypothermia and increased to 1.16 after rewarming. We found a significant fall in TEE in sedated, curarized, and ventilated ischemic stroke patients during moderate hypothermia. Indirect calorimetry appears to be a useful tool for measuring energy expenditure in these patients, as predicted basal energy expenditure overestimates the caloric requirements during hypothermia.

Physical activity but not energy expenditure is reduced in obese adolescents: a case-control study , ,

The influence of physical activity on body weight in children and adolescents is controversial. The objective was to test the hypothesis that the intensity and duration of physical activity differ between obese and normal-weight adolescents, with no difference in estimated energy expenditure. We compared physical activity in 18 (8 males, 10 females) obese [body mass index (in kg/m(2)) > 30] adolescents (14-19 y) with that in a matched, normal-weight (BMI < 27) control group. Total energy expenditure (TEE) was measured with the doubly labeled water method, and physical activity was measured simultaneously by accelerometry. The physical activity level was determined as the ratio of TEE to the resting metabolic rate (RMR) and activity energy expenditure as 0.9 TEE minus RMR. Accelerometry data included total physical activity (counts x min(-1) x d(-1)), accumulated and continuous duration of activity, and continuous 10-min periods of physical activity of moderate intensity. There was no significant difference in adjusted (analysis of covariance) TEE, RMR, or AEE between groups. The physical activity level was significantly lower (P < 0.05) in the obese group. No sex x group interaction was observed. Differences in total physical activity (P < 0.001), accumulated time (P < 0.05), continuous time (P < 0.01), and continuous 10-min periods of physical activity of moderate intensity (P < 0.01) were observed between groups. Obese adolescents are less physically active than are normal-weight adolescents, but physical activity-related energy expenditure is not significantly different between groups. The data suggest that physical activity is not necessarily equivalent to the energy costs of activity.

PHYSICAL ACTIVITY BUT NOT ENERGY EXPENDITURE IS REDUCED IN OBESE ADOLESCENTS

BACKGROUND: The influence of physical activity (PA) on body weight in children and adolescents is controversial. OBJECTIVE: To test the hypothesis that the intensity and duration of PA differ between obese and normal-weight adolescents without any difference in energy expenditure estimates. METHODS: We compared physical activity in 18 (10 girls) obese (BMI > 30) adolescents (14–19 y) with that in a matched control group (BMI > 27). Total energy expenditure (TEE) was measured by the doubly labeled water (DLW) method and PA was measured simultaneously with by accelerometry. Physical activity level (PAL) was determined as the ratio of TEE to resting metabolic rate (RMR), and activity energy expenditure (AEE) as TEE minus RMR. Accelerometer data included total physical activity (counts/min/d), accumulated and continuous duration of activity, and continuous 10-min periods spent at moderate intensity or higher. RESULTS: There were no differences between groups in adjusted (ANCOVA) TEE, RMR, and AEE. PAL was significantly lower (P > 0.05) in the obese group. No gender by group interaction was observed. Accelerometer data indicated significant differences between groups in total physical activity (P > 0.001), and in accumulated time (P > 0.05), continuous time (P > 0.01) and continuous 10-min periods (P > 0.01) spent at moderate intensity or higher. CONCLUSIONS: Obese adolescents are less physically active than those of normal weight, but nevertheless there is no difference in physical activity related energy expenditure. The data suggest that physical activity is not necessarily equivalent to energy costs of activity.