Exercisers who find one activity they love and do it again and again often wonder if they're missing out on anything by not mixing up their routines.

In some respects, variety is irrelevant. If you're exercising primarily to control your weight, for example, your goal is to burn more calories than you take in - how you do it is up to you. Burning 100 calories will contribute to your goal whether it's by running or by washing your car.

Beware of Boredom

But engaging in different exercises has advantages. The more you do, the greater the odds you'll find a way to exercise and not get bored. Switching between exercises also may reduce the risk of injuries from repeated stress on the same parts of the body.

Finally, regular participation in a variety of activities means that regardless of changing seasons, locales, availability of exercise buddies, etc., you're likely to find a way to keep exercising.

Different Activities, Different Benefits

But the best argument for variety is the need to balance activities that offer different physical benefits - primarily, aerobic fitness and musculoskeletal fitness.

You'll build aerobic fitness by walking briskly, jogging, cycling, swimming, and playing sports with at least moderate intensity, such as tennis, basketball and soccer. Aerobic fitness reduces risk of heart disease, type 2 diabetes, colon cancer and obesity.

Musculoskeletal fitness comes from resistance-training activities such as weight lifting and stretching. Its benefits are centered on enhanced performance, but it may also reduce the risk of some chronic diseases.

Aerobic and musculoskeletal fitness each help combat the loss of function that often accompanies aging. A fit, active way of life increases not only longevity, but also quality of life. You've heard it before, but it's true: "Exercise adds years to your life and life to your years."

My Advice: Stay Balanced

I advise exercisers to engage in at least one aerobic activity and do some resistance exercise for musculoskeletal fitness, along with stretching to maintain joint flexibility. If there's one routine you like to do again and again in each category, that's OK. If you like to do different aerobic and musculoskeletal exercises at different times, all the better.

What really counts is to find the exercise program you like enough to stick with over time. Keep it up, and you'll reap the incredible benefits that come from a fit, active way of life.

About the Author: Susan Rutter -- Publisher, Nutritionist, and Instructor who assists patients and the public make healthy choices and changes in their lives. Web Site: Healthy YOUbbies. http://www.geocities.com/healthyoubbies/