Activity-related Energy Expenditure Research Articles

Nucleus accumbens D1- and D2-expressing neurons control the balance between feeding and activity-mediated energy expenditure

Accumulating evidence points to dysregulations of the Nucleus Accumbens (NAc) in eating disorders (ED), however its precise contribution to ED symptomatic dimensions remains unclear. Using chemogenetic manipulations in male mice, we found that activity of dopamine D1 receptor-expressing neurons of the NAc core subregion facilitated effort for a food reward as well as voluntary exercise, but decreased food intake, while D2-expressing neurons have opposite effects. These effects are congruent with D2-neurons being more active than D1-neurons during feeding while it is the opposite during running. Chronic manipulations of each subpopulations had limited effects on energy balance. However, repeated activation of D1-neurons combined with inhibition of D2-neurons biased behavior toward activity-related energy expenditure, whilst the opposite manipulations favored energy intake. Strikingly, concomitant activation of D1-neurons and inhibition of D2-neurons precipitated weight loss in anorexia models. These results suggest that dysregulations of NAc dopaminoceptive neurons might be at the core of EDs.

RELATIVE AND ABSOLUTE METABOLIC COST OF DAILY PHYSICAL ACTIVITIES ACROSS THE LIFESPAN

Abstract Americans spend over 90% of their activity related energy expenditure performing common daily activities. However, there is a gap in knowledge pertaining to potential age-related differences in the metabolic cost of performing these activities which diminishes proper physical activity prescription. We hypothesized age differences in both the absolute and relative metabolic cost of performing common daily physical. Participants (n=248, age: 20-94 yrs) performed 33 activities (e.g. dressing, walking, making a bed, gardening, computer work) in a standardized setting. A portable indirect calorimeter was worn for approximately 6-10 minutes to achieve steady-state metabolic rate. A graded exercise treadmill test was performed to quantify peak metabolic rate. A metabolic equivalent (MET as a function of 3.5 milliliter•min-1•kg-1) and percentage of peak were used to express absolute and relative metabolic rate, respectively. Watching television (1.0+/-0.36 METs; 15.6+/-5.7% of peak) produced the lowest and climbing stairs (6.2+/-2.2 METs; 84.8+/-17.0% of peak) elicited the highest metabolic rate. Results from mixed effect regression models adjusting for health conditions, demographics and anthropometry showed no association between absolute MET and age. However, when expressed relative to peak, adjusted models showed a strong association with age (0.66+/-0.33% per year, p=0.006). As an example, adults < 40 yrs old worked at 34.1+/-14.8% of peak during a leisurely walk while those 80+ years old worked at 64.2+/-16.3%. Aging is associated with a substantial increase in the relative metabolic cost of performing common daily physical activities. These results could have implications on prescribing physical activity older adults to achieve higher fitness.

Fitness, behavioral, and energetic trade-offs of different migratory strategies in a partially migratory species.

Alternative migratory strategies can coexist within animal populations and species. Anthropogenic impacts can shift the fitness balance between these strategies leading to changes in migratory behaviors. Yet some of the mechanisms that drive such changes remain poorly understood. Here we investigate the phenotypic differences, and the energetic, behavioral, and fitness trade-offs associated with four different movement strategies (long-distance and short-distance migration, and regional and local residency) in a population of white storks (Ciconia ciconia) that has shifted its migratory behavior over the last decades, from fully long-distance migration toward year-round residency. To do this, we tracked 75 adult storks fitted with GPS/GSM loggers with tri-axial acceleration sensors over 5 years, and estimated individual displacement, behavior, and overall dynamic body acceleration, a proxy for activity-related energy expenditure. Additionally, we monitored nesting colonies to assess individual survival and breeding success. We found that long-distance migrants traveled thousands of kilometers more throughout the year, spent more energy, and >10% less time resting compared with short-distance migrants and residents. Long-distance migrants also spent on average more energy per unit of time while foraging, and less energy per unit of time while soaring. Migratory individuals also occupied their nests later than resident ones, later occupation led to later laying dates and a lower number of fledglings. However, we did not find significant differences in survival probability. Finally, we found phenotypic differences in the migratory probability, as smaller sized individuals were more likely to migrate, and they might be incurring higher energetic and fitness costs than larger ones. Our results shed light on the shifting migratory strategies in a partially migratory population and highlight the nuances of anthropogenic impacts on species behavior, fitness, and evolutionary dynamics.

Exercise capacity and physical activity in COPD patients treated with a LAMA/LABA combination: a systematic review and meta-analysis

BackgroundPersistent airflow limitation and dyspnoea may reduce chronic obstructive pulmonary disease (COPD) patients exercise capacity and physical activity, undermining their physical status and quality of life. Long-acting muscarinic antagonists and long-acting beta-2 agonists (LAMA/LABA) combinations are amongst moderate-to-severe COPD recommended treatments. This article analyses LAMA/LABA combinations effect on COPD patients exercise capacity and physical activity outcomes.MethodsA systematic review and meta-analysis of double-blind randomized controlled trials comparing LAMA/LABA combinations against monotherapy or placebo was conducted.ResultsSeventeen articles were identified (N = 4041 patients). In endurance shuttle walk test and constant work rate cycle ergometry, LAMA/LABA combinations obtained better results than placebo, but not monotherapy, whereas in 6-min walking test, results favoured LAMA/LABA over monotherapy (four studies), but not over placebo (one study). Moreover, LAMA/LABA combinations obtained better results than placebo in number of steps per day, reduction in percentage of inactive patients and daily activity-related energy expenditure, and better than monotherapy when measuring time spent on ≥ 1.0–1.5, ≥ 2.0 and ≥ 3.0 metabolic equivalents of task activities.ConclusionsLAMA/LABA combinations in COPD patients provided better results than monotherapy or placebo in most exercise capacity and physical activity outcomes.

Prediction of activity-related energy expenditure under free-living conditions using accelerometer-derived physical activity

The purpose of the study was to develop prediction models to estimate physical activity (PA)-related energy expenditure (AEE) based on accelerometry and additional variables in free-living adults. In 50 volunteers (20–69 years) PA was determined over 2 weeks using the hip-worn Actigraph GT3X + as vector magnitude (VM) counts/minute. AEE was calculated based on total daily EE (measured by doubly-labeled water), resting EE (indirect calorimetry), and diet-induced thermogenesis. Anthropometry, body composition, blood pressure, heart rate, fitness, sociodemographic and lifestyle factors, PA habits and food intake were assessed. Prediction models were developed by context-grouping of 75 variables, and within-group stepwise selection (stage I). All significant variables were jointly offered for second stepwise regression (stage II). Explained AEE variance was estimated based on variables remaining significant. Alternative scenarios with different availability of groups from stage I were simulated. When all 11 significant variables (selected in stage I) were jointly offered for stage II stepwise selection, the final model explained 70.7% of AEE variance and included VM-counts (33.8%), fat-free mass (26.7%), time in moderate PA + walking (6.4%) and carbohydrate intake (3.9%). Alternative scenarios explained 53.8–72.4% of AEE. In conclusion, accelerometer counts and fat-free mass explained most of variance in AEE. Prediction was further improved by PA information from questionnaires. These results may be used for AEE prediction in studies using accelerometry

Calibration of an Accelerometer Activity Index among Older Women and Its Association with Cardiometabolic Risk Factors.

Traditional summary metrics provided by accelerometer device manufacturers, known as counts, are proprietary and manufacturer specific, making them difficult to compare studies using different devices. Alternative summary metrics based on raw accelerometry data have been introduced in recent years. However, they were often not calibrated on ground truth measures of activity-related energy expenditure for direct translation into continuous activity intensity levels. Our purpose is to calibrate, derive, and validate thresholds among women 60 years and older based on a recently proposed transparent raw data based accelerometer activity index (AAI), and to demonstrate its application in association with cardiometabolic risk factors. We first built calibration equations for estimating metabolic equivalents (METs) continuously using AAI and personal characteristics using internal calibration data (n=199). We then derived AAI cutpoints to classify epochs into sedentary behavior and intensity categories. The AAI cutpoints were applied to 4,655 data units in the main study. We then utilized linear models to investigate associations of AAI sedentary behavior and physical activity intensity with cardiometabolic risk factors. We found that AAI demonstrated great predictive accuracy for METs (R2=0.74). AAI-based physical activity measures were associated in the expected directions with body mass index (BMI), blood glucose, and high density lipoprotein (HDL) cholesterol. The calibration framework for AAI and the cutpoints derived for women older than 60 years can be applied to ongoing epidemiologic studies to more accurately define sedentary behavior and physical activity intensity exposures which could improve accuracy of estimated associations with health outcomes.

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 of Physical Activity Level With Risk of Dementia in a Nationwide Cohort in Korea

Current guidelines recommend 500 to 999 metabolic equivalent (MET)-minutes per week (MET-min/wk) of regular physical activity. However, evidence regarding the association between light-intensity physical activity (LPA) and dementia in older adults is inconsistent. To assess the association between physical activity and new-onset dementia, focusing on the dose-response association between physical activity and dementia and the association of LPA with the incidence of dementia. For this nationwide retrospective cohort study, we analyzed 62 286 participants aged 65 years or older without preexisting dementia who had available health checkup data from the Korean National Health Insurance Service database from January 2009 to December 2012. Participants were followed up until December 31, 2013, and data analysis was performed from July 2020 to January 2021. Physical activity level was assessed using a standardized, self-reported questionnaire at baseline. Physical activity-related energy expenditure (in MET-min/wk) was calculated by summing the product of frequency, intensity, and duration. Incidence of dementia. Incidence rates were calculated by dividing the number of events by the person-time at risk (presented as the incidence per 1000 person-years). Hazard ratios (HRs) and 95% CIs for dementia were analyzed according to physical activity level. Competing risk regression was performed by using the Fine-Gray subdistribution hazard model, with mortality as the competing risk for dementia events. Multivariable regression models were constructed with adjustment for various patient characteristics. Incident dementia occurring 2 years after enrollment was assessed, and separate analyses included all follow-up periods. Restricted cubic spline curves were used to examine the association of continuous values of physical activity with dementia. Among 62 286 participants, 60.4% were women, and the mean (SD) age was 73.2 (5.3) years. During a median follow-up of 42 months, 3757 participants (6.0%) developed dementia, and the overall incidence was 21.6 per 1000 person-years. Compared with inactive individuals (0 MET-min/wk), insufficiently active (1-499 MET-min/wk; mean, 284 MET-min/wk), active (500-999 MET-min/wk; mean, 675 MET-min/wk), and highly active participants (≥1000 MET-min/wk; mean, 1627 MET-min/wk) showed 10% (adjusted hazard ratio [HR], 0.90; 95% CI, 0.81-0.99), 20% (adjusted HR, 0.80; 95% CI, 0.71-0.92), and 28% (adjusted HR, 0.72; 95% CI, 0.60-0.83) reduced dementia risk, respectively. Thus, a progressive decrease in the adjusted HR of dementia was associated with increasing physical activity level, and a restricted cubic spline curve showed that this association started with a low amount of total physical activity. This association was consistent regardless of age, sex, and other comorbidities or after censoring for stroke. Compared with total sedentary behavior, even a low amount of LPA (1-299 MET-min/wk; mean, 189 MET-min/wk) was associated with reduced dementia risk (adjusted HR, 0.86; 95% CI, 0.74-0.99). In older adults, an increased physical activity level, including a low amount of LPA, was associated with a reduced risk of dementia. Promotion of LPA might reduce the risk of dementia in older adults.

Maternal Adiposity and Energy Balance After Normotensive and Preeclamptic Pregnancies.

BackgroundPreeclampsia is a major pregnancy complication associated with long-term maternal cardiometabolic disease. Research generally is focused on metabolic and pathophysiological changes during pregnancy; however, there is much less focus on the early postpartum period in subjects who suffered preeclampsia. The aim of this study was to (1) characterize energy intake and expenditure 6 months following normotensive and preeclamptic pregnancies and (2) examine associations between energy balance, body composition, insulin resistance measures (HOMA-IR), and clinical characteristics.DesignA cross-sectional study 6 months following normotensive (n = 75) and preeclamptic (n = 22) pregnancies was performed. Metabolic measurements included anthropometrics measures, body composition via bioelectrical impedance analysis, 24-h energy expenditure via SenseWear Armbands, energy intake via a 3-day food diary, and serum metabolic parameters.ResultsSix months following preeclampsia, women had a significantly higher weight (77.3 ± 20.9 kg vs 64.5 ± 11.4 kg, P = 0.01), fat mass percentage (FM%; 40.7 ± 7.4% vs 34.9 ± 8.1%, P = 0.004), and insulin resistance (HOMA-IR 2.2 ± 1.5 vs 1.0 ± 0.7, P = 0.003), as well as reduced HDL levels (1.5 ± 0.4 mmol/L vs 1.8 ± 0.4 mmol/L, P = 0.01) compared to normotensive women. Women post-preeclampsia had lower activity-related energy expenditure (P = 0.02) but a decreased total energy intake (P = 0.02), leading to a more negative energy balance compared to their normotensive counterparts (−1942 kJ/24 h vs −480 kJ/24 h, P = 0.02).ConclusionIncreases in insulin resistance and FM%, reduced high-density lipoprotein, and more sedentary lifestyles characterize the postpartum period following preeclamptic compared with normotensive pregnancies. Early post-preeclampsia interventions, such as lifestyle behavior change, should be implemented and assessed to determine whether they reduce long-term cardiometabolic risk in women who experienced preeclampsia during pregnancy.

Stretch-Shortening Cycle Potentiation and Resistance Training-Induced Changes in Walking Economy/Ease and Activity-Related Energy Expenditure in Older Women.

Hunter, GR, Singh, H, Martins, C, Baranauskas, MN, and Carter, SJ. Stretch-shortening cycle potentiation and resistance training-induced changes in walking economy/ease and activity-related energy expenditure in older women. J Strength Cond Res 35(5): 1345-1349, 2021-Use of elastic energy to improve economy and ease of walking may be important for older adults. The purpose of this investigation was to determine whether baseline (i.e., untrained) stretch-shortening cycle potentiation (SSCP) was associated with potential changes in free-living activity-related energy expenditure (AEE) after supervised exercise training. Sedentary, postmenopausal women (n = 64) between 60 and 74 years of age were evaluated before and after 16 weeks of combined aerobic and resistance training. Assessments included: (a) body composition (dual-energy X-ray absorptiometry), (b) resting energy expenditure (indirect calorimetry), (c) submaximal and maximal walking (treadmill/indirect calorimetry), (d) total energy expenditure (doubly labeled water), and (e) one repetition maximum performed on an incline leg press and SSCP (calculated as the difference between concentric and countermovement leg press throw). Results indicated that baseline SSCP was related (r = -0.29; p < 0.02) to changes in AEE. However, subjects who possessed a high baseline SSCP did not increase SSCP or AEE, whereas subjects with low to moderate baseline SSCP demonstrated a significant increase in both SSCP (low +0.54 and moderate +0.47 m·s-1) and AEE (low +158 and moderate +333 kcal·d-1) post-training (all p less than 0.05). Our findings suggest that among subjects with low to moderate baseline SSCP, 16 weeks of combined aerobic and resistance training can increase SSCP and free-living AEE. However, subjects with high baseline SSCP may require tailored exercise to increase SSCP and possibly AEE.

Effect of endurance training on copper, zinc, iron and magnesium status.

Physical activity related energy expenditure, environmental stresses, body composition, dietary intake, etc., are key factors influencing the nutritional requirements of minerals. The present study was designed to study the nutritional status of metals with respect to extensive endurance training. The participants of the study were navy sailors (N.=37, mean age±SD: 25.2±4.8 y) undergoing one month of endurance training. Nutritional status was assessed by determining their body composition using bioelectrical impedance (BIA), food intake and urinary excretion levels. Fasting blood samples were taken to separate plasma and red blood cells for analysis of copper, zinc, magnesium and iron and certain metal dependent enzymatic biomarkers. Endurance training significantly decreased the plasma levels of copper (P<0.01), zinc and iron (P<0.05) while in erythrocytes a significant (P<0.001) decrease was observed only for Mg and Zn. There was a concomitant increase (P<0.05) in urinary Zn excretion. In addition, the concentrations of certain metal dependent enzymatic biomarkers like RBC metallothionein (P<0.05) and carbonic anhydrase (P<0.01) (Zn biomarker), plasma ferritin (Fe biomarker) (P<0.001) and RBC Mg ATPase (Mg biomarker) (P<0.05) decreased after physical activity. The findings of the present study suggested the increased requirements of these minerals during physical activity.

Day and night changes in energy expenditure of patients on automated peritoneal dialysis

Automated peritoneal dialysis (APD) treatment for end-stage kidney disease affords patients a degree of autonomy in everyday life. Clinical investigations of their energy expenditure (EE) are usually based on resting EE, which could mask day and night variations in EE. The aim of this study, therefore, was to compare the components of EE in APD patients and healthy control (C) subjects. Patients treated with APD for more than 3 months were compared with C volunteers matched for age and lean body mass (LBM). Biochemical analyses were performed and body composition was determined by DEXA to adjust EE to LBM. Total EE, its different components and respiratory quotients (RQ) were measured by a gas exchange method in calorimetric chambers. Spontaneous total and activity-related EE (AEE) were also measured in free-living conditions over 4 days by a calibrated accelerometer and a heart rate monitor. APD (n=7) and C (n=7) patients did not differ in age and body composition. REE did not differ between the two groups. However, prandial increase in EE adjusted for dietary energy intake was higher in APD patients (+57.5±12.71kcal/h) than in C subjects (+33.8±10.5kcal/h, p=0.003) and nocturnal decrease in EE tended to be lower in APD patients undergoing dialysis sessions (- 4.53±8.37kcal/h) than in subjects (- 11.8±7.69kcal/h, p=0.059). Resting RQ (0.91±0.09 vs 0.81±0.04, p=0.032) and nocturnal RQ (0.91±0.09 vs 0.81±0.04, p=0.032) were significantly higher in APD patients, indicating a preferential use of glucose substrate potentially absorbed across the peritoneum. AEE was lower in APD patients (595.9±383.2kcal/d) than in C subjects (1205.2±370.5kcal/d, p=0.011). In contrast, energy intakes were not significantly different (1986±465 vs 2083±377kcal/d, p=0.677). Although the two groups had identical resting EE, APD patients had a higher prandial increase in EE, a lower activity-related EE and higher resting and nocturnal RQ than healthy subjects.

Novel Input for Designing Patient-Tailored Pulmonary Rehabilitation: Telemonitoring Physical Activity as a Vital Sign-SMARTREAB Study.

Physical inactivity may be a consequence of chronic diseases but also a potential modifiable risk factor. Therefore, it should be clinically assessed as a vital sign of patients’ general physical condition prior to any exercise-based intervention. This cross-sectional study describes physical activity in the daily life of 100 chronic respiratory patients before pulmonary rehabilitation, comparing subjective and objective measures. The assessment combined the International Physical Activity Questionnaire (IPAQ) and 4-day accelerometer and oximeter telemonitoring with SMARTREAB technology, assessing heart rate, transcutaneous oxygen saturation and activity-related energy expenditure by metabolic equivalent of task (MET). According to IPAQ, 49% of patients had a moderate level of physical activity in daily life (PADL), a weekly mean level of 2844 ± 2925 MET.min/week, and a mean sedentary time of 5.8 ± 2.7 h/day. Alongside this, SMARTREAB telemonitoring assessed maximum activity ranging from 1.51 to 4.64 METs, with 99.6% daytime spent on PADL below 3 METs and 93% of patients with daily desaturation episodes. Regardless of the self-reported IPAQ, patients spend at least 70% of daytime on PADL below 2 METs. SMARTREAB was demonstrated to be an innovative methodology to measure PADL as a vital sign, combining oximetry with accelerometry, crossmatched with qualitative patient data, providing important input for designing patient-tailored pulmonary rehabilitation.

Validity Of Combined Heart Rate And Accelerometry To Predict Activity Energy Expenditure In Older Adults

PURPOSE: The present study compared physical activity related energy expenditure (PAEE) as predicted by group calibrated algorithm combining accelerometry and heart rate. METHODS: N=45 older adults with and without cardiac risk performed a protocol consisting of simulated daily living activities (resting period, light, moderate and vigorous physical activity including walking in different speeds and stair climbing) and a cycle ergometer test (25W + 25W every 2 minutes). PAEE was concurrently assessed by indirect calorimetry (IC) and by combined heart rate (HR) plus uniaxial accelerometry (ACC). Raw HR and ACC data were transformed to PAEE using a published branched equation model. Estimated and measured PAEE were compared using Bland-Altman plots. SUMMARY OF RESULTS: Preliminary results of n=12 healthy older adults without cardiac risk (8 male and 4 female, 71.9 ± 5.2 years) showed lower ACC+HR-estimated PAEE for clustered activities (including cycle ergometer test) and resting period (clustered activities 2.17 ± 1.17 Kcal/min; resting period 0.19 ± 0.17 Kcal/min) than PAEE measured by IC (clustered activities 2.93 ± 1.27 Kcal/min; resting period 0.61 ± 0.40 Kcal/min). The Bland & Altman plots' limits of agreement were between -2.28 and +0.94 kcal/min. Visual inspection showed that the dispersion of the absolute differences between ACC+HR and IC seemed to increase with higher measured values. The correlation between combined ACC+HR-PAEE and IC-PAEE was rρ = 0.86. CONCLUSION: First results indicate that branched equation models based on combined ACC+HR registrations may underestimate PAEE in older people but appear sufficiently valid for the assessment of mean PAEE in groups. If the relatively large limits of agreement were to persist throughout this ongoing study, they would indicate a limited validity of existing ACC+HR branched equations for the individual assessment of PAEE in older adults. More research is needed to determine whether combined ACC+HR assessments are superior to simple ACC to measure physical activity in older adults.

The effect of web-based educational intervention on physical activity-related energy expenditure among middle-aged women with overweight and obesity: An application of social cognitive theory

IntroductionObesity and being overweight are serious health problems worldwide. One of the most effective strategies for controlling and treating obesity is physical activity (PA), which unfortunately is not performed desirably by people. The present study aims to determine the effectiveness of web-based educational intervention based on social cognitive theory (SCT) on physical activity-related energy expenditure among women with overweight and obesity. MethodsThis quasi-experimental study was conducted on 91 middle-aged women with overweight and obesity (47 in the intervention and 44 in the control group). The intervention group received theory-based training through the web. Data were collected by a questionnaire consisting of demographic, SCT constructs and a seven-day standard PA inventory in three stages (before, two-weeks and three-months after training). Data were analyzed by SPSS software v.22. ResultsAfter intervention, the differences between the two groups in terms of SCT constructs were statistically significant as follows: knowledge (P = 0.012), self-regulation (P = 0.001), self-efficacy (P = 0.013), social-support from friends (P = 0.002) and family (P = 0.001) except for the outcome-expectation (P = 0.663). The level of energy expenditure from PA in the intervention group had a significant increase during the study (P = 0.005), while the control group was significantly decreased (P = 0.024). ConclusionThe findings of this study showed the effectiveness of the web and theory-based intervention in increasing awareness, promoting the major constructs of SCT and, finally, improving the PA behavior in women with overweight and obesity. The experience of this study showed that e-learning could be welcomed by these people and encouraged them to engage in PA.

Assessment of energy expenditure during high intensity cycling and running using a heart rate and activity monitor in young active adults.

Although high intensity physical activities may represent a great proportion of the total energy expenditure in active people, only sparse studies have investigated the accuracy of wearable monitors to assess activity related energy expenditure (AEE) during high intensity exercises. Therefore, the purpose of the present study was to investigate the accuracy of the Actiheart, a light portable monitor estimating AEE based on heart rate (HR) and activity counts (ACT), during two popular activities (running and cycling) performed at high intensities. The benefit of an individual calibration of the HR-AEE relationship established during a preliminary maximal test was also evaluated. AEE was estimated in eighteen active adults (4 women and 14 men; 25 ± 4 yr) with indirect calorimetry using a respiratory gas analysis system (reference method) and the Actiheart during 5-min running and cycling at 60, 75 and 85% of maximal oxygen uptake (VO2max) previously determined during a maximal test performed on a treadmill or cycle ergometer. For the Actiheart, AEE was estimated either using the group or individual calibrated equations available in the dedicated software, and their respective HR, ACT or combined HR/ACT algorithms. When the HR algorithm was used for cycling and the HR or HR/ACT algorithms for running, AEE measured by the Actiheart increased proportionally to exercise intensity from 60 to 85% VO2max (P<0.001). Compared to indirect calorimetry, the Actiheart group calibrated equations slightly to moderately underestimated (3 to 20%) AEE for the three exercise intensities (P<0.001). Accuracy of AEE estimation was greatly improved by individual calibration of the HR-AEE relationship (underestimation below 5% and intraclass correlation coefficient [ICC]: 0.79-0.93) compared to group calibration (ICC: 0.64-0.79). The Actiheart enables to assess AEE during high intensity running and cycling when the appropriate algorithm is applied. Since an underestimation was present for group calibration, an individual and sport-specific calibration should be performed when a high accuracy is required.

1272Physical activity and mortality with and without cardiovascular disease

Abstract Background/Introduction Physical activity has been shown to reduce mortality in a dose-response fashion. Current guidelines recommend 500 to 1,000 MET-min per week of regular physical activity. However, evidence is limited regarding the specific dose-response relationship in patients with cardiovascular disease. Purpose Our aim was to compare the impact of physical activity on mortality in primary versus secondary cardiovascular prevention. Methods We analyzed 441,798 individuals with complete information on physical activity levels between 2009 and 2015 were extracted from a population-based cohort (National Health Insurance Service-National Health Screening cohort). Physical activity measured by self-report questionnaires. A rating of 2.9, 4.0, and 7.0 METs were assigned for light-intensity, moderate-intensity, and vigorous-intensity activities, respectively. Physical activity-related energy expenditure (MET-min/week) was calculated by summing the product of frequency, intensity, and duration. The level of physical activity was classified into 0, 0 to 499, 500 to 999, 1,000 to 1,499, and ≥1,500 MET-min/week. Study participants were stratified by the presence of cardiovascular disease, defined as prior myocardial infarction, ischemic heart disease, prior stroke, and/or chronic heart failure. The main study outcome was all-cause mortality. The median follow-up duration was 5.9 years. Results Individuals with cardiovascular disease had lower physical activity levels and a higher risk of mortality than those without cardiovascular disease. There was an inverse relationship between the physical activity level and the mortality risk in both groups. The benefit in the secondary prevention group was shown to be greater than that in the primary prevention group: every 500 MET-min/week increase in physical activity resulted in a 14% and 7% risk reduction in mortality in the secondary and primary prevention groups, respectively (interaction P&lt;0.001). In addition, while individuals without cardiovascular disease benefited the most between 0 and 500 MET-min/week of physical activity, the benefit in those with cardiovascular disease continued above 500 to 1,000 MET-min/week. The adjusted mortality risk of individuals with cardiovascular disease who performed a high level of physical activity (≥1,000 MET-min/week) was shown to be comparable to or lower than that of their counterparts without cardiovascular disease. Adjusted risk of mortality Conclusion Individuals with cardiovascular disease may benefit from physical activity to a greater extent than do healthy subjects without cardiovascular disease. Clinicians should encourage patients with cardiovascular disease to maintain a physically active lifestyle as much as possible.

Exercise Comes of Age: Brain Training

Dementia is a growing global concern engendering immense societal cost and personal suffering. It is the leading cause of dependence and disability in the older population in Australia, as it is worldwide. Prevention is critical to interrupt the spiral of physical, emotional, and cognitive suffering globally as the demographic shifts continue to expand this epidemic. Decades of research into pharmacological treatments to either prevent or treat dementia in healthy adults or those with memory loss have not been successful, and thus recent attention has turned to lifestyle and risk factor reduction. Notably, robust animal and epidemiological data strongly support the role of physical exercise in modifying brain structure and cognitive performance across the lifespan. For example, in prospective studies higher self-reported physical activity is associated with a 20–30 % reduction in incident dementia, while objective measurement of total activity-related energy expenditure has been linked to a substantial 91 % reduction in the risk of incident cognitive impairment over 5 yrs. It has been estimated from such prospective cohort studies that reducing physical inactivity by only 25 % would prevent 1 million cases of dementia worldwide annually. Mild cognitive impairment (MCI), defined as objective and subjective cognitive decline with preserved functional independence, offers a unique window of opportunity in high-risk individuals to target neuroplasticity when the brain is still potentially able to adapt to beneficial stimulation. Building on the observational literature above, some exercise trials have led to improved cognitive performance, but the effect sizes in cognitively healthy adults have been statistically negligible, heterogeneous, and of questionable clinical relevance. However, exercise trials in those with established MCI or dementia have reported larger positive effects, particularly when the prescriptions are sufficiently robust. Unfortunately, the mechanisms of exercise benefit, or the reasons for broad individual variation in cognitive adaptations are very poorly defined. Such mechanistic insight, and longterm, robust research is critical if we are to confirm and optimise a brain-training exercise prescription so as to enhance neuroplasticity and improve cognition in high-risk or already impaired individuals.

Dose–response relationship between physical activity and mortality in people with non-communicable diseases: a study protocol for the systematic review and meta-analysis of cohort studies

IntroductionThis study protocol outlines our planned systematic review and dose-response meta-analysis of postdiagnosis physical activity and mortality in people with non-communicable diseases (NCDs).Methods and analysisThis study is based on the...

737-P: Physical Activity Levels among Latino Adults with Type 2 Diabetes

Physical activity (PA) is a cornerstone of type 2 diabetes (T2D) treatment. In the U.S, Latinos bear a disproportionate cardio-metabolic disease burden from T2D. The aim of this study was to determine levels and patterns of PA among free-living Latino adults with T2D comparing a ubiquitous consumer device with an established accelerometry method. Participants (57 women and 31 men, BMI (kg/m2) 32.2±7.9 and 29.9±4.5, waist circumference (WC cm) 97.1±30.1 and 93.7±33.0, and HbA1C% 8.0±2.0 and 8.1±1.8, respectively) wore a research device (Actigraph, wGT3X-BT, AG) on the dominant hip and a consumer device (Fitbit Charge 2™, FB) on the non-dominant wrist to monitor daily activity for one week [outcome measures estimated by steps and energy expenditure (EE)]. AG median steps/weekday (M-F) was 6990 (range 1091-25884) compared to 9329 (288-31669) using the FB data (p≤0.01). Both devices recorded higher number of steps on weekdays compared to weekends [AG 5608 (1066-19892) and FB 7577 (1023-23603), both p≤0.05]. This corresponded to activity-related energy-expenditure of 442 (63-1821) kcals/weekday and 361 (58-1396) kcals/weekend using AG and 2344 (1135-5802) kcals/weekday and 2178 (1378-4930) kcals/weekend by FB (including resting metabolic rate). AG and FB data were highly correlated to each other for daily steps (r’s&amp;gt;0.7, p’s&amp;lt;0.01) but not for estimated EE. Men were more active than women on average and maintained their PA throughout the week. However, women decreased their PA on weekends (by around 1700 steps or 130 kcals/day by AG) while their weekday PA was negatively correlated with BMI and WC (p&amp;lt;0.05). Using AG, only 2 participants reached 6,000 steps in an hour at least twice during the week and 58% never reached 3,000 steps in 30 minutes on any day of the week (a common moderate to vigorous intensity PA goal). In conclusion, to incentivize PA in Latino adults with T2D, considerations need to be made of the timing of measurements (weekdays versus weekends), gender and technologies used. Disclosure W.C. Bevier: Research Support; Self; Eli Lilly and Company. N.M. Glantz: Research Support; Self; Eli Lilly and Company. C.B. Hoppe: Research Support; Self; Eli Lilly and Company. J. Morales: Research Support; Self; Eli Lilly and Company. A.J. Larez: Research Support; Self; Eli Lilly and Company. M.M. Conneely: Research Support; Self; Eli Lilly and Company. K.Y. Chen: None. D. Kerr: Advisory Panel; Self; Ascensia Diabetes Care, Novo Nordisk A/S, Sanofi. Research Support; Self; Lilly Diabetes. Stock/Shareholder; Self; Glooko, Inc. Funding Eli Lilly and Company