Similarly, a second Swedish study in the same journal suggests that young men who undertake a regime of endurance exercise for more than 5 hours a week may increase their risk of developing irregular heart rhythm ( atrial fibrillation) – a known risk factor for stroke.
In the German study, the researchers tracked the frequency and intensity of physical activity and the survival of 1,038 people with stable coronary artery heart disease for 10 years.
All the participants, most of whom were over 60 years old, had attended a cardiac rehabilitation programme to help them exercise regularly and ward off a further heart attack or stroke. Most were male, overweight, current or former smokers, and with a history of heart attacks and high blood pressure.
Around 40% were physically active 2 to 4 times each week; 30% did more; 30% did less. Overall, around 1 in 10 said they rarely or never did any exercise.
Heart attack and stroke
After taking account of other factors, the researchers found that the most physically inactive were around twice as likely to have a heart attack or stroke as those who took regular exercise. Also, they were around 4 times as likely to die of cardiovascular and all other causes.
However, somewhat surprisingly, those who did the most strenuous daily exercise were also more than twice as likely to die of a heart attack or stroke, the findings show.
Commenting on the findings in a statement, Julie Ward, senior cardiac nurse at the British Heart Foundation, says: "Being physically active is good for your heart. However, what this research confirms is that the risk to our health comes from doing too much or too little exercise.
"That’s why guidelines recommend moderate intensity exercise as the best way forward. These are activities that get you breathing a little harder, get your heart rate a little higher and get you feeling a little warmer."
Experts recommend that adults should do at least 30 minutes of moderate intensity exercise on at least 5 days a week to reap general health benefits.
"It is worth remembering though that if you have been diagnosed or had treatment for coronary heart disease in the past it’s important to discuss your exercise plan with your GP," Julie Ward adds.
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