Maximal aerobic capacity in african-american and caucasian pre
-pubertal children.
Trowbridge, Christina A, Barbara A Gower, Tim R Nagy, Gary R Hunter,
Margarita S Treuth, and Michael I Goran.
Division of Physiology and Metabolism, Department of Nutrition
Sciences, University of Alabama at Birmingham
APStracts 4:0150E, 1997.
The purpose of this study was to examine differences in resting,
submaximal and maximal (VO2max) oxygen consumption in African
-American (n = 44) and Caucasian (n = 31) pre-pubertal children aged
5-10 years. Resting oxygen consumption was measured via indirect
calorimetry in the fasted state. Submaximal VO2 and VO2max were
determined during an all-out, progressive treadmill exercise test
appropriate for children. Dual-energy X-ray absorptiometry (DXA) was
used to determine total fat mass (FM), soft lean tissue mass (LTM),
and leg soft LTM. Doubly labeled water was used to determine total
energy expenditure (TEE) and activity energy expenditure (AEE). A
significant effect of ethnicity (p < 0.01) was found for VO2max,
but not resting or submaximal VO2, with African-American children
having absolute VO2max 15 % lower than Caucasian children (1.21 +
0.032 vs 1.43 +__ 0.031 L/min, respectively). The lower VO2max
persisted in African-American children after adjusting for soft LTM
(1.23 +__ 0.025 vs 1.39 +__ 0.031 L/min; p < 0.01), leg soft LTM
(1.20 +__ 0.031 vs 1.43 +__ 0.042 L/min; p < 0.01), and soft LTM
and FM (1.23 +__ 0.025 vs 1.39 +__ 0.031 L/min; p < 0.01). The
lower VO2max persisted after also adjusting for TEE (1.20 +__ 0.02
vs 1.38 +__ 0.0028 L/min p < 0.001 ) and AEE (1.20 +__ 0.024 vs
1.38 +__ 0.028 L/min; p < 0.001). In conclusion, our data indicate
that African-American and Caucasian children have similar rates of
oxygen consumption at rest and during submaximal exercise, but VO2max
is 15% lower in African-American children, independent of soft LTM,
FM, leg LTM, TEE, and AEE.
Received 28 April 1997; accepted in final form 3 July 1997.
APS Manuscript Number E193-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 24 July 1997