Which age-related change contributes to the decline in cardiorespiratory fitness?

• A. Reduced elasticity of heart and blood vessels
• B. Increased lung capacity
• C. Higher red blood cell volume
• D. Higher VO2 max

Answer: (A)

Arterial stiffness is a key age-related change that lowers cardiorespiratory fitness. As people age, arteries and the heart walls tend to become less elastic, so they don’t expand and recoil as well. This makes the heart work harder to push blood through the vessels and dampens the rapid increase in blood flow to muscles during exercise. The result is a lower maximal cardiac output and a reduced ability to deliver and utilize oxygen during activity, which shows up as a decline in VO2 max and overall fitness.

The other options don’t fit with the typical aging pattern. Lung capacity generally declines rather than increases with age, so that wouldn’t explain a decline in fitness. Higher red blood cell volume would improve oxygen transport, not contribute to a decline. A higher VO2 max is a sign of better fitness, not a cause of decline.