In trained individuals, what is the estimated decrease in VO2 max per decade after the age of 30?

In trained individuals, the estimated decrease in VO2 max per decade after the age of 30 is approximately 5%. This decline reflects the effects of aging on aerobic capacity, which is influenced by factors such as a reduction in maximum heart rate, decreased muscle mass, and changes in the cardiovascular and respiratory systems. While trained individuals often maintain higher levels of physical fitness and may have better conditioning than sedentary individuals, their VO2 max still tends to decline over time due to physiological aging processes that are unavoidable.

The figure of 5% per decade serves as a general guideline in exercise physiology literature, indicating that even in well-conditioned athletes, there are observable declines in performance measures like VO2 max due to age. It's important to recognize that consistent training and physical activity can mitigate some of the decline, but the 5% estimate is useful for understanding the average expected changes in trained populations.