Good news! You don't have to kill yourself with crunches to get a sleek stomach.

But it turns out that you do need to get your heart rate up. Aerobic exercise is key to banishing both the deep belly fat and the superficial doughy stuff that give you a pooch.

Going the Distance
How much aerobic exercise does it take to trim a tummy? In a recent study, overweight people who jogged, cycled, or hit the elliptical for about 3 hours a week had the best belly-busting outcome -- as long as they exercised at an up-tempo pace. Not ready to go that distance yet? Try walking briskly for just a couple of hours per week. That's enough to at least keep belly swelling in check.

It's All Good
It's almost a guarantee that people who do nothing as they age will be watching their waists grow along with their risks of diabetes and cardiovascular disease. So whether you do it a little or a lot, sweat is still a sweet way to manage your middle. In addition to up-tempo exercise, try these tips and tools for training your body and toning your tummy:

• Heart Rate Recovery Quiz -- It helps you measure your fitness gains.
• Trunk Tune-Up -- Use these easy exercise-ball moves to tone tummy muscles.
• The YOU Diet -- It's a proven waist-management plan.
• Walking Wish List -- Read about all the wishes that walking can help grant.

This tip originally ran on 3/11/2008.