Oxygen uptake efficiency slope as a useful measure of cardiorespiratory fitness in morbidly obese women.

Onofre T; Oliver N; Carlos R; Felismino A; Corte RC; Silva E; Bruno S.

PLoS ONE [Electronic Resource]. 12(4):e0172894, 2017.

Cardiopulmonary assessment through oxygen uptake efficiency slope (OUES)
data has shown encouraging results, revealing that we can obtain important
clinical information about functional status. Until now, the use of OUES
has not been established as a measure of cardiorespiratory capacity in an
obese adult population, only in cardiac and pulmonary diseases or
pediatric patients. The aim of this study was to characterize submaximal
and maximal levels of OUES in a sample of morbidly obese women and analyze
its relationship with traditional measures of cardiorespiratory fitness,
anthropometry and pulmonary function.
Thirty-three morbidly obese women
(age 39.1 +/- 9.2 years) performed Cardiopulmonary Exercise Testing (CPX)
on a treadmill using the ramp protocol. In addition, anthropometric
measurements and pulmonary function were also evaluated. Maximal and
submaximal OUES were measured, being calculated from data obtained in the
first 50% (OUES50%) and 75% (OUES75%) of total CPX duration. In one-way
ANOVA analysis, OUES did not significantly differ between the three
different exercise intensities, as observed through a Bland-Altman
concordance of 58.9 mL/min/log(L/min) between OUES75% and OUES100%, and
0.49 mL/kg/min/log(l/min) between OUES/kg75% and OUES/kg100%. A strong
positive correlation between the maximal (r = 0.79) and submaximal (r =
0.81) OUES/kg with oxygen consumption at peak exercise (VO2peak) and
ventilatory anaerobic threshold (VO2VAT) was observed, and a moderate
negative correlation with hip circumference (r = -0.46) and body adiposity
index (r = -0.50) was also verified. There was no significant difference
between maximal and submaximal OUES, showing strong correlations with each
other and oxygen consumption (peak and VAT).
These results indicate that
OUES can be a useful parameter which could be used as a cardiopulmonary
fitness index in subjects with severe limitations to perform CPX, as for
morbidly obese women.