Oxygen uptakes adjusted for body composition in normal-weight and obese adolescents.
OBJECTIVE
To test whether resting oxygen uptake (VO(2)), submaximal VO(2), and maximal VO(2) (VO(2max)) differs between obese adolescents (n = 18; BMI > 30) and a matched normal-weight control group after adjustment for differences in fat-free mass (FFM) and fat mass (FM).


METHODS
FFM and FM were assessed by DXA. Resting VO(2), submaximal VO(2), and VO(2max) were measured by indirect calorimetry.


RESULTS
There was no difference in resting VO(2) between groups after adjusting for FFM and FM. Submaximal VO(2) did not differ between groups after adjusting for body weight. Percentage VO(2max) and NET VO(2) (VO(2max) - resting VO(2)) were significantly higher in the obese group during submaximal exercise, however not after adjusting for body weight. VO(2max) was not significantly different between groups after adjusting for FFM.


CONCLUSIONS
When body compositions are appropriately controlled for, resting VO(2), submaximal VO(2), and VO(2max) do not differ between obese and normal-weight adolescents. These data suggested that the higher relative VO(2) observed in obese adolescent subjects is due to their higher FM and not to an impaired VO(2max) even though they may be less physically active.
Ekelund
Ulf
U
Medical Research Council Epidemiology Unit, Cambridge, United Kingdom. ue202@medschl.cam.ac.uk
Franks
Paul W
PW
Wareham
Nicolas J
NJ
Aman
Jan
J
D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D001823:Body Composition; D001835:Body Weight; D002153:Calorimetry, Indirect; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010101:Oxygen Consumption; D012146:Rest