7. a. The surgeon general’s guidelines suggest exercising at a moderate level most if not all days of the week.

The old guidelines recommended 20-30 minutes of strenuous exercise three times a week at 60-85 percent of your maximum heart rate to get any cardiovascular benefit, said Julie Pauls, MS, PT, president of the consulting firm PhysiCare for Women in The Woodlands. "The new [1996] guidelines are that you should exercise most if not all days for 30 minutes," she said. The activities need not be strenuous—moderate exertion is fine.