Estimation of Free-Living Energy Expenditure by Heart Rate and Movement Sensing: A Doubly-Labelled Water Study |
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Authors: | S?ren Brage Kate Westgate Paul W Franks Oliver Stegle Antony Wright Ulf Ekelund Nicholas J Wareham |
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Institution: | 1. MRC Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom.; 2. Department of Clinical Sciences, Lund University, Malmö, Sweden.; 3. Department of Physics, University of Cambridge, Cambridge, United Kingdom.; 4. European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge, United Kingdom.; 5. MRC Human Nutrition Research, Cambridge, United Kingdom.; CNRS, FRANCE, |
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Abstract: | BackgroundAccurate assessment of energy expenditure (EE) is important for the study of energy balance and metabolic disorders. Combined heart rate (HR) and acceleration (ACC) sensing may increase precision of physical activity EE (PAEE) which is the most variable component of total EE (TEE).ObjectiveTo evaluate estimates of EE using ACC and HR data with or without individual calibration against doubly-labelled water (DLW) estimates of EE.Design23 women and 23 men (22–55 yrs, 48–104 kg, 8–46%body fat) underwent 45-min resting EE (REE) measurement and completed a 20-min treadmill test, an 8-min step test, and a 3-min walk test for individual calibration. ACC and HR were monitored and TEE measured over 14 days using DLW. Diet-induced thermogenesis (DIT) was calculated from food-frequency questionnaire. PAEE (TEE ÷ REE ÷ DIT) and TEE were compared to estimates from ACC and HR using bias, root mean square error (RMSE), and correlation statistics.ResultsMean(SD) measured PAEE and TEE were 66(25) kJ·day-1·kg-1, and 12(2.6) MJ·day-1, respectively. Estimated PAEE from ACC was 54(15) kJ·day-1·kg-1 (p<0.001), with RMSE 24 kJ·day-1·kg-1 and correlation r = 0.52. PAEE estimated from HR and ACC+HR with treadmill calibration were 67(42) and 69(25) kJ·day-1·kg-1 (bias non-significant), with RMSE 34 and 20 kJ·day-1·kg-1 and correlations r = 0.58 and r = 0.67, respectively. Similar results were obtained with step-calibrated and walk-calibrated models, whereas non-calibrated models were less precise (RMSE: 37 and 24 kJ·day-1·kg-1, r = 0.40 and r = 0.55). TEE models also had high validity, with biases <5%, and correlations r = 0.71 (ACC), r = 0.66–0.76 (HR), and r = 0.76–0.83 (ACC+HR).ConclusionsBoth accelerometry and heart rate may be used to estimate EE in adult European men and women, with improved precision if combined and if heart rate is individually calibrated. |
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