How the Heart Benefits from Exercise

Keeping Weight Down, Blood Vessels Open and Heartbeats Steady

Scientists are still discovering different ways the heart benefits from regular exercise. But there’s no question that it does. By the early 2000s, researchers had established that people who vigorously exercised on a regular basis -- either by jogging, swimming or participating in another aerobic activity -- lowered their heart disease risk by 20%.

Even lower-intensity exercise, such as walking briskly for three miles or longer several times weekly, results in a 10% risk reduction. And when placed against heart disease’s fearsome role as America’s number-one killer, these lowered odds add up to many lives saved and improved. About 860,000 U.S. residents suffer a heart attack each year, and nearly a half-million die from cardiac problems.

But how does exercise produce cardiovascular benefits? The answer is multi-pronged, with physical activity not only strengthening the heart muscle itself but enhancing blood vessel function and even promoting the ability of the central nervous system to regulate heart rhythm.

Opening Blood Vessels

Forced to beat faster during exercise to keep up with the body’s oxygen demands, the heart muscle over time will assume a lower resting pulse -- an important sign of its strength. But the arteries surrounding the heart benefit as well, with exercise increasing their flexibility and reducing the stiffness normally associated with aging blood vessels among the sedentary. These more flexible blood vessels are better able to dilate, lowering the chance of high blood pressure -- an important risk factor for heart disease.

Other risk factors include age, gender, smoking, high cholesterol and family history. Until the age of 65 -- when risk evens out --- men have a greater chance of developing heart problems than women. And African-Americans suffer higher rates of cardiac disease than Caucasians at least partly because of greater levels of associated conditions, such as diabetes, that contribute to heart disease.

Steadying Heartbeats

Regular exercise, noted a 2008 article in the Journal of Applied Physiology, also appears to boost the autonomic nervous system, which controls involuntary functions such as breathing and heartbeat, helping to reduce irregularities in the heart's rhythm that can result in sudden cardiac arrest. Physical activity also improves or negates other heart disease risk factors, including obesity and high cholesterol.

“The mechanisms underlying the benefit of exercise, however, require further study,” writes Anthony S. Leicht, the article’s lead author.

What isn’t ambiguous is that aerobic activity is clearly the best kind of exercise for those who want to reduce their cardiac disease risk. Aerobic activity -- which increases the pulse to between 50% and 85% of a person’s maximum heart rate -- produces better results than more sedentary activities, such as gardening or a leisurely walk (though doctors insist that any exercise is better than none for heart health).

A 2008 study in the American Journal of Physiology -- Regulatory, Integrative and Comparative Physiology reported that short, intense bursts of aerobic activity three times per week offered the same cardiac benefits as longer endurance exercises (brisk walking, cycling) five times per week. Fitness specialists also recommend interval training, which alternates intense exercise with less-intense periods; an example would be to alternate brisk walking for two minutes with periods of sprinting for 30 seconds at a time.

Other forms of aerobic activity, which should be done at least three times per week for 40 to 60 minutes for maximum cardiac benefit, include rowing, stair climbing, bike riding, jumping rope, dancing and cross-country skiing.

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