The relationship between physical activity dose and fitness is poorly understood.

 

In an examination of this relationship, Church and colleagues randomly assigned sedentary, overweight or obese postmenopausal women to 1 of 3 exercise groups with an energy expenditure of 50%, 100%, or 150% of the National Institutes of Health Consensus Development Panel recommended physical activity dose or to a no-exercise control group to measure any change in aerobic fitness during the 6-month intervention.

 

The investigators found a graded dose-response improvement in fitness across the 3 levels of exercise training that was similar across subgroups based on age, weight, baseline fitness, and ethnicity/race.