Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

Area of Science:

• Exercise Physiology
• Cardiorespiratory Fitness Assessment
• Clinical Exercise Testing

Background:

• Maximal oxygen uptake (VO2max) is a key indicator of aerobic fitness and mortality risk.
• Estimating VO2max using equations can introduce significant individual error, impacting clinical decisions.
• Current estimation methods may not accurately reflect VO2max in diverse populations undergoing cardiopulmonary exercise testing (CPX).

Purpose of the Study:

• To quantify the estimation error of VO2max in cycle ergometry within a clinical testing setting.
• To develop and validate novel sex-specific equations for VO2max estimation.
• To minimize the error associated with VO2max prediction in adults.

Main Methods:

• 1715 adults underwent maximal cardiopulmonary exercise testing (CPX) on a lower limbs cycle ergometer (LLCE) using a ramp protocol.
• Percentage error (E%) was calculated between measured VO2max and VO2max estimated by a modified ACSM equation.
• New estimation equations were developed for the general population (C-GENERAL) and separately for men (C-MEN) and women (C-WOMEN).

Main Results:

• Measured VO2max was significantly higher in men compared to women.
• The modified ACSM equation showed substantial error for both sexes, particularly women (-14.7 ± 17.4%).
• Sex-specific equations (C-MEN and C-WOMEN) significantly reduced VO2max estimation error compared to the general equation and the modified ACSM equation for both men and women.

Conclusions:

• Sex-specific equations enhance the accuracy of VO2max estimation in cycle ergometry.
• While reduced, the error of estimate for VO2max using these new equations on LLCE was not entirely eliminated.
• These findings support the use of sex-specific equations for more precise VO2max assessment in clinical exercise testing.