High levels of exercise can help to prevent stiffening of the arteries in middle-aged men and women. Researchers at Indiana University studied 21 men and 28 women, 33 of whom were highly active swimmers who exercised vigorously for more than 200 minutes per week. The remaining 16 participants exercised moderately or not at all. The study found highly active middle-aged men and women had significantly less arterial stiffness than those who were inactive or exercised moderately. Among men and women in the inactive group, men had less arterial stiffness than women, suggesting exercise may be more beneficial for women than men with regard to reducing the risk of developing arterial stiffness that can lead to cardiovascular disease. Researchers noted that this may be because inactive women tend to be more sedentary than inactive men.