To improve your heart and lung fitness, aim for 30 to 60 minutes of aerobic exercise three to four times a week.

Teens need at least 60 minutes of moderate to vigorous physical activity on most days for good health and fitness and for healthy weight during growth.

You can't walk across a room without huffing and puffing. Your arms get tired unpacking a bag of groceries. You're carrying more and more excess body weight. And you can't remember the last time you got any real exercise.

You know it's important to stay active but still find yourself falling back on old habits. What can you do? Planning for exercise isn't hard if you make it a priority.

The teen years often bring a sharp drop in physical activity, especially for girls.

You can lose weight by dieting, exercising, or a combination of both. Including exercise into your daily routine offers other benefits besides weight control.

If you've tried a dozen diets but the pounds always sneak back, you may be able to lose them for good by making strength-training an integral part of your weight-loss program.

Walking is easy because you can do it almost anywhere and at any time. It also offers a range of health benefits.

As a busy person with family, work, and civic responsibilities, how can you find time for yet another activity?

Starting as early as your 20s and throughout your 30s, you'll naturally start to lose muscle -- and gain fat at a rate of about 2 percent per decade, especially if you have a sedentary job or lifestyle.