Dancing provides excellent benefits, as does tai chi, which integrates aerobic, strengthening, stretching and balance. (Fotolia / February 19, 2014)

You don't have to be an athlete to make your heart stronger. Engaging in as little as 15 minutes of exercise per day can benefit your heart and even extend your life span.

In one study, exercising 15 minutes a day for eight years reduced all-cause mortality by 14 percent and increased life expectancy by three years. Every additional 15 minutes of exercise a day lowered mortality during the study period by an additional 4 percent.

"Exercise produces significant benefit by lowering levels of damaging inflammation that affects heart and artery health," says Dr. Daniel Forman, a cardiologist and geriatrician at Harvard-affiliated Brigham and Women's Hospital, Boston, Mass. Dr. Forman has a special interest in how exercise training can improve cardiovascular health and well-being in seniors.

Exercise also helps by improving the body's ability to fight oxidative stress, a chemical byproduct of cellular energy generation. Oxidants damage cells and change the way our bodies function, increasing our vulnerability to illness.

"Exercise lowers your vulnerability to heart attacks, heart failure, peripheral artery disease, and arrhythmias. Not only do you feel better, but also you function better," says Dr. Forman.

PRESCRIPTION FOR EXERCISE

The most well-known path to cardiovascular strength is aerobic exercise. This type of exercise makes your heart stronger and able to use oxygen better. It also improves circulation and lowers blood pressure.

"Exercise doesn't have to be rigorous. Low-intensity exercise can be beneficial. Just start easily and build up gradually," says Dr. Forman. "The important thing is to commit yourself to doing it regularly."

Daily aerobic exercise is recommended. Other types of exercise that complement aerobic exercise and add to its heart-building benefit include strength training and stretching. Each should be done two or three times a week.

"Strength training is especially important, since it builds up strength in muscles and bone, which helps with walking, daily activity, and metabolism. Stretching strengthens joints and improves stability," Dr. Forman explains.

Slow aerobic exercise at the start and end of activity--so-called warm-ups and cool-downs--are particularly important for elderly individuals. Warm-ups provide gradual increases in heart and breathing rates and blood flow in the limbs, which make more vigorous exercise much safer. A cool-down after exercise helps avoid dizziness and falls as the heart slows down.

Dr. Lawrence P. Cahalin, professor of physical therapy at the University of Miami's Miller School of Medicine, conducts research on exercise and heart disease with Dr. Forman. The two experts offer a simple prescription for exercise that almost anyone can follow. The key is to start gently and move gradually.

"If the thought of exercise holds you back, don't call it exercise; call it physical activity," Dr. Forman recommends. "Pick the activity you like doing, because you're more likely to do it."

If you need motivation, join a gym. Many people find the camaraderie good incentive. Many gyms have recumbent bikes that provide an excellent aerobic workout in comfortable position. Gyms also have trainers who will be happy to show you how to use hand weights safely.

There are many alternatives to traditional exercise, too.

"Dancing provides excellent benefits. So does tai chi, which integrates aerobic, strengthening, stretching, and balance," says Dr. Cahalin.

It shouldn't take long before you develop the capacity to exercise comfortably for 15 minutes or longer. When you reach this point, don't stop: longer durations and higher intensities provide even greater cardiovascular and musculoskeletal benefits. Just remember to keep doing it. It also doesn't take long to lose the benefits you've gained.

GOOD CHOICES

1. Aerobic exercise