Last updated: Mar 02, 2016

OK, OK, so just about everyone knows your metabolism begins to drop—and your dress size starts to go up—once you hit your 30s. But what you may not know is that it doesnt have to. The main reason your body starts to pack on the pounds isnt because youre aging and your metabolism is slowing—its because youre exercising less (or just not enough).

So whats the harm in taking a break from your workouts and letting your belt out a couple of notches? That weight gain and muscle loss can really snowball over the years, says JoAnn Manson, MD, chief of preventive medicine at Harvards Brigham and Womens Hospital, leading to an added 20 to 30 pounds by the end of your 50s, not to mention brittle bones and increased risks of heart disease and type 2 diabetes.

You can avoid all that by doing our workouts designed specifically for your 30s, 40s, and 50s by Michele Olson, PhD, professor of exercise science at Auburn University. Theyll help you maintain your weight, kick up your metabolism, build muscle and bone density, and stay healthy inside, too. Ready to stop the aging clock?