L. Davidson et al., FREE-LIVING ENERGY-EXPENDITURE OF ADULT MEN ASSESSED BY CONTINUOUS HEART-RATE MONITORING AND DOUBLY-LABELED WATER, British Journal of Nutrition, 78(5), 1997, pp. 695-708
Free-living energy expenditure was estimated by doubly-labelled water
(DLW) and continuous heart-rate (HR) monitoring over nine consecutive
days in nine healthy men with sedentary occupations but different leve
ls of leisure-time physical activity. Individual calibrations of the H
R-energy expenditure (EE) relationship were obtained for each subject
using 30 min average values of HR and EE obtained during 24 h whole-bo
dy calorimetry with a defined exercise protocol, and additional data p
oints for individual leisure activities measured with an Oxylog portab
le O-2 consumption meter. The HR data were processed to remove spuriou
s values and insert missing data before the calculation of EE from sec
ond-order polynomial equations relating EE to HR. After data processin
g, the HR-derived EE for this group of subjects was on average 0.8 (SE
M 0.6) MJ/d, or 6.0 (SEM 4.2)% higher than that estimated by DLW. The
diary-respirometer method, used over the same 9 d, gave values which w
ere 1.9 (SEM 0.7) MJ/d, or -12.1 (SEM 4.0)% lower than the DLW method.
The results suggest that HR monitoring can provide a better estimate
of 24 h EE of groups than the diary-respirometer method, but show that
both methods can introduce errors of 20% or more in individuals.