A study at Louisiana State University looked at 500 women ages 45-75 who had become overweight and were living sedentary lives. They found 71 minutes of moderate intensity cardiovascular exercise per week not only prevented a loss of fitness, but also actually resulted in an increase in fitness. At the end of the six-month study, none of the women lost weight or saw a drop in blood pressure, but the main benefit was important – they had improved their aerobic fitness and were able to move a little longer and faster without becoming winded. That is important because aerobic fitness alone is a key predictor of longevity. The study did find that the more exercise women did, the better off they were.