Which individual is most likely to experience improvements in VO2 max with relatively low training intensities?

• A. A person with high VO2max already
• B. A person with low VO2max prior to training
• C. A trained athlete
• D. An obese person with normal VO2 max

Answer: (B)

Initial fitness level strongly influences how VO2 max responds to training; those who start with a lower VO2 max tend to show improvements even with relatively modest training intensities. When someone's baseline VO2 max is low, the body has substantial room to adapt, and early aerobic gains come from a mix of central and peripheral changes: the heart can become more efficient, stroke volume can increase, and the muscles can boost mitochondrial density and capillarization, all of which raise oxygen delivery and utilization. These adaptations can happen with lower-intensity training because the stimulus is sufficient to provoke meaningful physiological remodeling for someone starting from a lower level. In contrast, individuals who already have a high VO2 max are closer to their natural ceiling; further improvements require more substantial or different training stimuli, so gains with low-intensity programs are limited. An athlete or a person who is already trained also has less room for big VO2 max increases, and while an obese person with normal VO2 max might improve, the greatest relative improvement from modest effort tends to occur in someone with a low starting VO2 max.