Scale of VO(2peak) in obese and non-obese adolescents by different methods.

BACKGROUND Peak oxygen uptake (VO(2peak)) can be defined as the highest oxygen rate consumed during exhaustive or maximal exercise. The evaluation of the aerobic fitness can be expressed as relative to body mass, but this procedure may not fully remove differences when heavy subjects are assessed. Thus, the allometric scaling procedure is an attractive strategy to compare individuals with large differences in body mass. OBJECTIVE Investigate VO(2peak) in obese and non-obese individuals using body mass correction (conventional) and allometric scaling (allometric) methods and how these methods apply when subjects of different genders exercise on a treadmill. METHODS VO(2peak) relative to body weight and measured by the allometric method were compared in 54 obese and 33 non-obese adolescents (10 a 16 years). Indirect calorimetry was used to assess VO(2peak) during a maximal test. The allometric exponent was calculated taking into account individual body mass. Then, VO(2peak) was corrected by the allometric exponent. The comparisons were performed using a repeated measures two-way ANOVA (p<0.05). RESULTS The absolute VO(2peak) was higher (p<0.05) in the obese girls (2.80+/-0.69) compared to non-obese ones (2.00+/-0.24), but this association was not observed for the male subjects (p>0.05). However, VO(2peak) calculated by the conventional method was higher (p<0.05) among non-obese individuals in both genders (girls: 41.45+/-3.85; boys: 49.81+/-7.12) in comparison to the obese subjects (girls: 32.11+/-4.48; boys: 37.54+/-6.06). The allometric VO(2peak) was similar (p>0.05) between the groups. CONCLUSION The obese showed lower VO(2peak) values than non-obese individuals when assessed by the conventional method. However, when the allometric scaling method was applied, differences disappeared.