Just as regular exercise can reduce the risk of a heart attack, physical activity also may help prevent "brain attack"--more commonly known as stroke. In its recently released guidelines, the Prevention Advisory Board of the National Stroke Assn. recommends taking "a brisk walk for as little as 30 minutes a day" as one of 10 strategies to help prevent stroke, America's leading cause of adult disability.
"Exercise is so important to cardiovascular health in general and to reducing the risk of coronary heart disease that we've long suspected it might protect against stroke as well," says Philip B. Gorelick, professor of neurology at Chicago's Rush Medical College and chairman of the National Stoke Assn. panel. "Now we have the evidence to say that physical activity is an exceedingly important factor."
A stroke occurs when blood circulation to the brain fails, most often as a result of blockage of a blood vessel in the brain or neck. In recent years, some experts have begun calling this condition a brain attack to reflect its similarity to heart attack and to increase awareness of its urgent nature.
Stroke is the third leading cause of death in the United States after heart disease and cancer. It takes 160,00 lives each year. About 731,000 Americans have strokes annually, according to the association.
"Although stroke remains a leading cause of death, disability and health care expenditures, it can be prevented," according to the new guidelines, which were published in Marchin the Journal of the American Medical Assn.
The guidelines, which constitute the first-ever national expert consensus on stroke prevention, cite six risk factors: hypertension, history of heart attack, elevated cholesterol levels, atrial fibrillation (a type of abnormal heart rhythm), diabetes mellitus and asymptomatic carotid artery disease.
The guidelines also highlight several lifestyle factors that can contribute to stroke risk, including smoking, excessive alcohol consumption and a diet high in fat and sodium. Regular exercise may help prevent strokes, the recommendations note, in part because physical activity positively affects many risk factors.
"Physical activity can help control blood pressure, and that's the leading risk factor for stroke," notes Edgar J. Kenton, professor of clinical neurology at Thomas Jefferson University in Philadelphia and a member of the executive committee of the American Heart Assn.'s Stroke Council. "Physical activity improves cardiovascular conditioning and helps keep the heart in shape, which is a major risk factor."
Exercise also can improve cholesterol ratios and reduce the risk of diabetes. Also, Kenton says, "people who exercise are more health-conscious and are more likely to have healthy behaviors such as not smoking or drinking to excess and having a good diet."
Recent research has helped strengthen the link between physical activity and stroke prevention. People who exercise for an hour a day cut their risk for stroke nearly in half, according to a study of 11,130 Harvard University alumni, published in the fall in Stroke: Journal of the American Heart Assn.
Researchers found that people who expended 2,000 kilocalories each week--the equivalent of a one-hour brisk walk five days a week, had a 46% lower risk of stroke than those who did little to no exercise. People who expended 1,000 kilocalories a week--the equivalent of walking briskly for 30 minutes a day, five days a week--had about a 24% reduction in stroke risk.
"Walking, stair-climbing and participating in moderately intense activities such as dancing, bicycling and gardening were shown to reduce the risk of stroke," says the study's lead author, I-Min Lee, an assistant professor of epidemiology at the Harvard School of Public Health.
While it's generally not necessary to get a physician's approval to go out for a walk, sedentary people who want to begin a program of vigorous exercise should consult a doctor first. Getting regular checkups is essential to stroke prevention, since knowing health measures such as blood pressure and cholesterol levels are important in reducing risk of the disease.
In addition to getting regular exercise, the National Stroke Assn.'s prevention guidelines recommend:
* Knowing your blood pressure and having it checked as least once a year.
* Finding out whether your have atrial fibrillation or high cholesterol.
* Quitting smoking, drinking in moderation, if at all, and eating a diet lower in fat and salt.
* Asking your doctor if you have circulation problems, following your doctor's recommendations if you are diabetic and seeking immediate medical attention if you experience any stroke symptoms. Stroke symptoms include sudden numbness or weakness of face, arm or leg; sudden confusion; trouble speaking or understanding; sudden trouble seeing or walking; and dizziness or sudden severe headache with no known cause.