Your doctor recommends that you get active and exercise more. But you're concerned about the impact of exercise on your bones, joints and muscles. Perhaps you have arthritis, or you're sedentary and overweight. You have a hard time believing you can exercise at all, no less in the water. But that's what your doctor suggests: water workouts.

Done correctly, water workouts can give you gains similar to those on land, including aerobic fitness, muscular strength and endurance, flexibility and better balance. Doctors recommend aquatic exercise because:

• Water's buoyancy supports your weight. When you're submersed up to your neck, the water cancels out about 90 percent of your body weight, significantly reducing stress on your weight-bearing joints, bones and muscles. Instead of landing on a hard surface with your full weight jarring you, you land with only 10 percent of your body's weight. This reduces your risk of injury.
• When you're submerged in water, your circulation may increase, improving your cardiovascular health.
• The pressure of the water on your body can reduce swelling if you have painful injuries.
• Water offers resistance, which strengthens your muscles as you push against it.
• Since the effects of gravity diminish in water, you can do stretching exercises that you may not be able to do on land.

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Everyone can benefit from aquatic exercise. But it's a prime option for someone who:

• Has arthritis or other joint problems
• Is overweight or obese
• Is sedentary and wants to ease into an exercise program
• Is recovering from an injury or surgery and has his or her doctor's permission
• Has a back problem
• Has weak leg muscles
• Is pregnant
• Is older

Think aquatic exercise is for you? Before you ease into the water:

• Talk with your doctor. If you're over 40 and live with a chronic health condition such as asthma, diabetes or heart disease, ask your doctor if aquatic exercise is OK, considering your overall health.
• Sign up for a class. You can learn all the right moves by starting with a class. Call a health club, university fitness center, or public sports and recreation center in your area to see if aquatic exercise classes are available. If they are, drop in on a class or two. Stay after class to talk with the instructor or someone in the class to get your questions answered before you sign up.
• Ask about the instructor's credentials. Look for an instructor who's certified in cardiopulmonary resuscitation (CPR) and trained in water safety instruction by organizations such as the U.S. Water Fitness Association or the Aquatic Exercise Association.
• Check out the latest equipment. Shoes made to be worn in the water provide you with better traction on the bottom of the pool. Flotation devices keep you on top of the water during deep-water exercises.
• Alert your instructor. Before your first class, let your instructor know about any special conditions, such as arthritis, that might affect your workout.
• Enjoy yourself. Besides the obvious fitness benefits, working out in the water can be fun. You'll meet new people and make new friends. And many classes include music and dance.

Water workouts can help you reach your fitness goals without pain or injury. They can add cross-training variety to your existing exercise routine or offer a safe and fun way to start an exercise program. So jump on in — the water's fine.