All women go through menopause, usually between the ages of 46 and 54. Their periods stop, and they can no longer get pregnant. Postmenopausal women also have lower heart function. This study investigated whether menopause influences heart function and exercise capacity. Twenty-five women between ages 45 and 58 signed up to exercise three times a week for 12 weeks. Of these women, 11 premenopausal and 14 postmenopausal. Each workout included four sets of high-intensity effort on a bike for four minutes. All of the women got fitter after 12 weeks of exercise. They were able to use more oxygen and work harder during an exercise test. However, women who had gone through menopause improved less than those who had not. The researchers also found differences in heart muscle mechanics between the two groups. This study is the first to suggest that menopause may affect the increase in fitness that comes with regular exercise. More studies are needed to find out how menopause affects heart function and general fitness. This may then change how women exercise after menopause.