How much does VO2 max decrease per decade in health sedentary individuals after the age of 25-30?

The value that represents the average decline in VO2 max for healthy sedentary individuals after the age of 25-30 is around 8-10% per decade. This decline is largely attributed to changes in various physiological factors including reduced cardiovascular efficiency, muscle mass, and overall physical activity levels as individuals age.

As individuals become more sedentary, the body becomes less efficient at oxygen utilization due to decreased aerobic capacity. The 8-10% figure is supported by numerous studies which have shown that without regular aerobic training, a significant reduction in VO2 max occurs as a natural part of the aging process. This emphasizes the importance of maintaining regular physical activity throughout life to help mitigate the effects of aging on cardiorespiratory fitness.