VOA常速英语:Sporadic Physical Activity Increases Risk of Heart Attack

Doctors the world over tell their patients to exercise for better health. But people who seldom or never exercise need to be extra cautious about engaging in strenuous physical activity. A new study shows that for these people, a sudden burst of activity, like jogging or sex, can be deadly.

You hear this often: "Check with your doctor before you start a new exercise program." A new study shows the wisdom of that advice.

Each year, millions of people find themselves in the emergency room after a heart attack because they overdid it during an exercise routine, or a bout of love-making.

Regular cardiovascular exercise reduces the risk of heart problems. But for the couch potatoes of the world - people who are sedentary - suddenly launching into a cardio program or having sex can lead to a heart attack.

Doctors at Tufts University Medical Center in Boston studied the problem and found a direct link between exercise and heart attack for these patients. Doctors Jessica Paulus and Issa Dahabreh reviewed 14 studies of the exercise-heart attack connection, mostly involving men between the ages of 55 and 64.

"For those individuals who were unaccustomed to regular physical activity or who did not typically exercise, this risk was much higher than for those individuals who were regular exercisers," said Paulus.

The study showed the greatest risk is during the activity and for up to two hours afterward. Should anyone interpret this as an excuse not to exercise, however, Paulus said they should think again.

"If they are unaccustomed to exercising but they’d like to start becoming more physically active, they should do so very gradually and under the care and supervision of a physician."

Dr. Dahabreh also pointed out that regular exercise is good even for people who have a higher risk for heart attack, because it conditions the heart to beat more slowly during a strenuous workout or sexual activity.

"People who exercise frequently, regularly, several times per week, will then have a much smaller increase (in heart rate) while they are involved in these specific activities," said Dahabreh.

The study appears in the Journal of the American Medical Association.