Climate-related corrections for improved estimation of energy
expenditure from heart rate in children.
Hebestreit, H., O. Bar-Or, C. McKinty, M. Riddell, and P. Zehr.
Children's Exercise and Nutrition Centre, Chedoke Hospital,
McMaster University, PO Box 2000 Station A, Hamilton/Ontario, Canada
L8S 3Z5
APStracts 2:0086A, 1995.
This study intended to determine the relationship between children's
heart rate (HR) and climatic heat stress at several O2-uptake (O2)
levels, and to construct equations and nomograms for an improved
estimation of energy expenditure (EE) from HR monitoring. On 4
occasions 12 girls and 8 boys (8-11 years) cycled for 5 min each at
35%, 55%, and 75% of peak O2 (random order), with rest periods in
between, in a climatic chamber. The randomly assigned conditions
were: 22 degrees C dry bulb temperature - 50% relative humidity (RH);
28 degrees C, 55%RH; 32 degrees C, 52%RH; or 35 degrees C, 58%RH. HR
and O2 were determined during the final 2 min of rest and exercise
bouts. HR measured at a temperature T (HRmeas.) was then related to a
HR at 22 degrees C which would have been expected to occur at an
identical O2 (HRcalc.22) using individual, 22 degrees C HR-O2
regression lines. HRcalc.22 could be estimated from HRmeas. x
(1.175032-[0.007956 x T]), with a mean error of prediction for the
entire group <1.5 beats x min-1 for each temperature. Conclusions:
1) Children's HR at a given O2 increases linearly with ambient
temperature at 22-35 degrees C, 50-60% RH, 2) HR can be corrected for
the influence of climate in groups of children resting and exercising
at the above conditions, thereby reducing the error of estimating EE
from HR.
Received 23 June 1994; accepted in final form 27 February 1995.
APS Manuscript Number A615-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 March 1995.