Heart rates during rest and exercise can indicate the risk of sudden death from a heart attack, showed a French study carried in the New England Journal of Medicine to be published on Thursday.
The study found the risk of sudden heart death was four times higher than normal for the people who had heart rates of more than 75 beats per minute during rest, or whose heart rates increased less than 89 beats per minute during exercise.
For those people whose heart rates decreased less than 25 beats in the minute after the end of exercise, the risk was twice the normal level.
The French study examined data from stress tests during physical exams between 1967-72 of 5,713 French men aged 42-53 who clinically had no heart problems. During a 23-year follow-up period, 81 of the people surveyed died of sudden heart death.
This is the first study that relates heart rate pattern during exercise with the risk of sudden death in healthy men, according to lead author Dr. Xavier Jouven, associate professor of cardiology and epidemiology at European Georges Pompidou Hospital in Paris.
According to the researchers, abnormal heart rate patterns during exercise and recovery from exercise indicate malfunction of the sympathetic and vagal nervous systems that are responsible for mediating the changes in heart rate.
Alterations in the neural control of cardiac function contribute to the risk of sudden death, they said.
(Xinhua News Agency May 12, 2005)
