A German study too much high-intensity exercise could increase the risk of death from a heart attack or stroke.
Another Swedish study found young men who participate in endurance exercise for more than five hours per week could increase their risk of experiencing an irregular heartbeat down the road, a BMJ-British Medical Journal news release reported.
The German study tracked the frequency and intensity of more than 1,000 people's workouts. All of the participants had stable coronary artery disease for a decade.
All of the participants were in their 60s and had been in a cardiac rehabilitation program to help encourage them to exercise more often.
Heart disease patients are recommended to participate in up to an hour of moderate intensity aerobics at least five times per week.
The study found 40 percent of the participants were physically active between two and four times per week, 30 percent exercised more often than that and another 30 percent exercised less often. One in 10 of the participants admitted to never exercising.
After taking into account outside factors the team found the most physically inactive were twice as likely to suffer a heart attack or stroke and four times more likely to die from any cause than those who were more active.
Those who did the most rigorous daily exercise were also twice as likely to die from a heart attack as those who stayed within the recommendations.
In the Swedish study the researchers interviewed more than 44,000 men between the ages of 45 and 79 about their exercise patterns over almost their entire lives. The participants' heart health was also tracked over a 12 year period.
The team found that men who had participated in intensive exercise for more than five hours per week at the age of 30 but did less at the age of 60 had a 49 percent higher risk of suffering the medical events.
"The benefits of exercise are definitely not to be questioned; on the contrary, they should be reinforced. The studies reviewed here, and future studies, will serve to [maximize] benefits obtained by regular exercise while preventing undesirable effects-just like all other drugs and therapies," the researchers said in the news release.
