Fat mass is negatively associated with the physiological ability of tissue to consume oxygen

Abstract

Aims:

To describe the relationship between variables related to body composition and peak oxygen uptake ($\dot{V}{O}_2$peak) and to verify whether fat mass can affect these relationships.

Methods:

Eighty participants underwent cardiopulmonary exercise testing to measure $\dot{V}{O}_2$peak and a body composition assessment to measure fat mass, fat free mass (FFM), and total body mass (BM).

Results:

There were significant relationships between $\dot{V}{O}_2$peak relative to FFM (fat free mass) (mL/kgFFM/min) and absolute fat mass (kg) (r=-0.50, p<0.001) and relative fat mass (%) (r=-0.56, p<0.001). Absolute $\dot{V}{O}_2$peak (L/min) had a high positive relationship with FFM (r=0.83, p<0.0001); the relationship between $\dot{V}{O}_2$peak (L/min) and FFM remained high and positive even when accounting for absolute fat mass (kg) (r=0.83, p<0.001). $\dot{V}{O}_2$peak relative to total body mass (mL/kgBM/min) showed a high negative relationship with relative fat mass (%) (r=-0.89, p<0.001) and a positive relationship with fat free mass (kg) (r=0.57, p<0.001), which did not change when accounting for fat mass (kg) (r=0.56, p<0.001).

Conclusion:

These data indicate that the physiological ability of tissue to consume oxygen ($\dot{V}{O}_2$peak in mL/kgFFM/min) is negatively associated with fat mass. Moreover, the individual’s cardiorespiratory capacity to transport oxygen for working muscles ($\dot{V}{O}_2$peak in L/min) is strongly related to absolute FFM, and this association is not affected by fat mass. Finally, a better body mass composition (high FFM and low fat mass) is important for aerobic physical fitness ($\dot{V}{O}_2$peak in mL/kgBM/min) and improved physiological ability of tissue to consume oxygen ($\dot{V}{O}_2$peak in mL/kgFFM/min).

Keywords:
aerobic physical fitness; body composition; peak oxygen uptake; obesity; fat free mass