title: Validity of a combined heart rate and motion sensor for the measurement of free-living energy expenditure in very active individuals.
abstract: OBJECTIVE
  The correct assessment of energy expenditure in very active individuals is important to ensure that dietary energy intake is sufficient. We aimed to validate a combined heart rate (HR) and motion sensor in estimating total (TEE) and activity energy expenditure (AEE) in males and females with high physical activity levels.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  Doubly-labelled water (DLW) was used to assess 7-day TEE in 12 male and female elite junior basketball players, aged 16-17 years. Resting energy expenditure (REE) was assessed with indirect calorimetry and AEE was calculated (AEE=TEE-RMR-0.1×TEE). Simultaneously, TEE and AEE were measured by combined HR and motion sensing. Individual HR calibration was performed with step-test. TEE and AEE were estimated from accelerometry and HR with individual (ACC+HRstep) and group calibration (ACC+HRgroup).
  
  
  RESULTS
  No mean differences were found between TEE and AEE from the ACC+HRstep and ACC+HRgroup with DLW. TEE values (kJ/day) from ACC+HRgroup and ACC+HRstep explained TEE from DLW by ∼60% and 53%, respectively whereas AEE (kJ/day) estimated by ACC+HRgroup and ACC+HRstep explained 53% and 41% of the variability of AEE from the reference method. Concordance correlation coefficients for TEE and AEE using ACC+HRgroup were 0.74 and 0.69, correspondingly while for ACC+HRstep values of 0.69 and 0.45 were found. Large limits of agreement were found for TEE and AEE using both ACC+HRgroup and ACC+HRstep.
  
  
  CONCLUSIONS
  ACC+HR models are a valid alternative to estimate TEE but not AEE in a group of highly active individuals however the considerable rate of equipment failure (∼50%) limits its usefulness.
authors.affiliation: Exercise and Health Laboratory, CIPER, Fac Motricidade Humana, Univ Tecn Lisboa, Portugal.
authors.forename: Diana A
authors.initials: DA
authors.lastname: Santos
authors.affiliation: Exercise and Health Laboratory, CIPER, Fac Motricidade Humana, Univ Tecn Lisboa, Portugal. Electronic address: analiza@fmh.utl.pt.
authors.forename: Analiza M
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Exercise and Health Laboratory, CIPER, Fac Motricidade Humana, Univ Tecn Lisboa, Portugal.
authors.forename: Catarina N
authors.initials: CN
authors.lastname: Matias
authors.affiliation: Exercise and Health Laboratory, CIPER, Fac Motricidade Humana, Univ Tecn Lisboa, Portugal.
authors.forename: João P
authors.initials: JP
authors.lastname: Magalhães
authors.affiliation: Department of Pediatrics, Children's Hospital Foundation University of Oklahoma Health Science Center, Oklahoma, Oklahoma City, OK, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Fields
authors.affiliation: Exercise and Health Laboratory, CIPER, Fac Motricidade Humana, Univ Tecn Lisboa, Portugal.
authors.forename: Cláudia S
authors.initials: CS
authors.lastname: Minderico
authors.affiliation: MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital Hills Road, University of Cambridge, UK; Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekelund
authors.affiliation: Exercise and Health Laboratory, CIPER, Fac Motricidade Humana, Univ Tecn Lisboa, Portugal.
authors.forename: Luís B
authors.initials: LB
authors.lastname: Sardinha
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009043:Motor Activity / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology
keywords: Accelerometry; Athletes; Doubly labelled water; Energy requirements; Heart rate monitoring; Indirect calorimetry