Unit of oxygen uptake efficiency slope

Katsuo Uchida
2018 The Journal of Physical Fitness and Sports Medicine  
The oxygen uptake efficiency slope (OUES) is the slope of a regression line of oxygen uptake (VO 2 ) on logarithmically converted minute ventilation (V E ) measured during incremental exercise: VO 2 = alog 10 V E + b. Here, a is the OUES. The higher the OUES, the more efficient the uptake of oxygen. The OUES has been widely accepted to estimate maximum oxygen uptake without maximal exercise. Nevertheless, the unit of OUES is unsettled in the literature having eight different descriptions. We
more » ... roduced a new equation for the OUES using resting VO 2 (VO 2 rest ) and resting V E (V E rest ): VO 2 = alog 10 (V E /V E rest ) + VO 2 rest . This equation is based on the mathematical principle that an antilogarithm such as V E /V E rest is dimensionless. It is clear from this equation that OUES has the same unit as VO 2 , because log 10 (V E /V E rest ) is just a numerical value without the unit. The new equation is written as VO 2 = alog 10 V E -alog 10 V E rest + VO 2 rest , where b = -alog 10 V E rest + VO 2 rest . The OUES value is obtained from Baba's original equation with VO 2 and V E during incremental exercise. The new equation is useful to identify the unit of OUES and the y-intercept b.
doi:10.7600/jpfsm.7.171 fatcat:5mr2eylexndpbpm44sls65fqfa