Which statement about sex differences in cardiorespiratory fitness is typical?

• A. Males typically have larger hearts and higher VO2 max
• B. Females always have higher VO2 max
• C. Sex differences are not observed in training response
• D. Only females benefit from aerobic training

Answer: (A)

In cardiorespiratory fitness, a common pattern is that men tend to have larger hearts and higher VO2 max values in absolute terms. A larger heart supports a greater maximal stroke volume, which helps raise maximal cardiac output and, therefore, VO2 max. In addition, men often have greater overall muscle mass and higher hemoglobin levels, both of which enhance oxygen transport and utilization during peak exercise. Yet, when VO2 max is adjusted for body size or fat-free mass, the differences between sexes become smaller, and both men and women can make substantial improvements with training. Both sexes benefit from aerobic training, though the exact adaptations can vary a bit due to hormonal and physiological differences. The other statements aren’t typical: females don’t consistently have higher VO2 max, training responses aren’t identical across sexes, and aerobic training benefits both sexes rather than only females.