Combined heart rate and activity improve estimates of oxygen
consumption and carbon dioxide production rates.
Moon, Jon K., and Nancy F. Butte.
USDA/ARS Children's Nutrition Research Center, Department of
Pediatrics, Baylor College of Medicine
APStracts 3:0251A, 1996.
Oxygen consumption () and carbon dioxide production () rates were
measured by electronically recording heart rate (HR) and physical
activity (PA). Mean daily and measurements by HR and PA were
validated in adults (female: n = 10, male: n = 10) using room
calorimeters. Thirteen linear and nonlinear functions of HR alone and
HR combined with PA were tested as models of 24-h and . Mean sleep
and were similar to basal metabolic rates and were accurately
estimated from HR alone [respective mean (SD) errors were -0.2 (0.8)%
and -0.4 (0.6)%]. The range of prediction errors for 24-h and was
smallest for a model that used PA to assign HR for each min to
separate active and inactive curves [: -3.3 (3.5) %, : -4.6 (3) %].
There were no significant correlations between or errors and subject
age, weight, fat mass, ratio of daily to basal energy expenditure
rate or fitness. ., and energy expenditure recorded for 3 free-living
days were 5.6 (0.9), 4.7 (0.8) mL min-1 kg-1 and 7.8 (1.6) kJ min-1,
respectively. Combined HR and PA measured 24-h and with a precision
similar to alternative methods.
Received 1 August 1995; accepted in final form 6 May 1996.
APS Manuscript Number A842-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 June 96