Smokers whose hearts don’t race when they exercise may have an extra reason to kick the habit, say researchers.
A study of 3,000 people published in Circulation, the journal of the American Heart Association, found that smokers whose hearts don’t speed up during exercise may be five times more likely to suffer a heart attack than non-smokers with normal heart rate reactions.
The theory is that nicotine stimulates autonomic nerve activity in a way that mimics the hormone epinephrine. With time, a person’s system may become dulled to the stimulation so that when epinephrine tries to speed the heartbeat, it has little effect.
“While everybody who smokes should quit, people who smoke and have an impaired heart-rate response to exercise are at really high risk,” said Dr. Michael Lauer, of the Cleveland Clinic, who wrote the study. “We should strongly counsel these people to stop smoking.”
