Too much exercise can be bad for the heart

Upper limit of physical activity - sports only in moderation sense

05/19/2014

Sufficient exercise is generally attributed to a preventive effect against diseases of the cardiovascular system such as hypertension or a heart attack. However, a recent study by the German Cancer Research Center (DKFZ) in Heidelberg makes it clear that only moderate exercise is suitable for cardiac patients. An excess of exercise and physical stress, however, shows adverse effects.

In their study, the scientists of the German Cancer Research Center have investigated how much sport offers the best protection against heart attacks and strokes. They stated, „That moderate effort has the cheapest effect two to four times a week“, while „less or no sport associated with significantly higher risk“ is the message of the DKFZ. However, it was also shown that subjects who trained daily were more at risk than a moderately active patient. This opens up a new discussion about the right amount of movement, because it obviously exists „an upper limit beyond which more sport brings no health benefit“, explained Professor Hermann Brenner from the German Cancer Research Center.

Study participants watched over ten years
To evaluate the long-term effects of physical activity, researchers have Ute Mons and Professor Hermann Brenner of the German Cancer Research Center according to own data „For over ten years, more than a thousand patients who had undergone clinical rehabilitation for coronary heart disease (myocardial infarction or acute coronary syndrome).“ Surveys after one, three, six, eight and ten years determined the athlete's activity. Accompanying was a documentation of the newly occurring cardiovascular complications (infarction, stroke). On the basis of the available data, the scientists determined a reference group of study participants, the „according to self-disclosure, exercising two to four times a week and thus representing the average level of activity.“

Daily exercise doubles the risk of serious cardiovascular events
Compared to the reference group, not only patients with no or very little exercise showed a significantly increased disease risk, but also „Even in patients who exercise daily, severe cardiovascular events were about twice as common as in the reference group“, reports the DKFZ. This non-linear relationship has become particularly clear if only the infarctions and strokes with fatal outcome were considered. However, the causes of this increase in risk among the most physically active patients remain unclear, as the exact circumstances of death were not documented in the study and therefore there is no information as to whether the fatal events may have occurred during or immediately after a physical exercise, the report said of the DKFZ.

Revise prevention recommendations
The scientists conclude that there are no doubts about the health benefits of exercise, but there seems to be a limit beyond which further physical activity may be detrimental. Professor Brenner emphasized that „the clinical recommendations for the secondary prevention of cardiovascular diseases take this into account accordingly“ should. However, the recommendation for moderate physical activity, as expressed for example by the German Hypertension League or the German Stroke Help Foundation for the prevention and treatment of hypertension, remains unaffected. In a recent press release, the prevention expert of the German Stroke Aid, dr. Bettina Begerow, once again reaffirms the importance of a minimum level of exercise for high blood pressure patients. Here, for example, a dog can help against hypertension, since the owners have to go for a walk with him several times a day.

Increasingly fatal cardiovascular events due to lack of exercise
Regardless of where the upper limit of exercise is, the study comes to the clear conclusion that the risk of fatal cardiovascular events is highest in patients who never or rarely move. About four times more cardiovascular deaths than in the reference group were observed here. However, the analysis may overestimate „the risk of patients from the most physically inactive group, because who is already sick and weakened, does not do sports“, explained Professor Brenner. Also, given the sample composition, it should be noted that the results of the study are by no means representative of the general population. Because all study participants suffered from a previous disease of the cardiovascular system and the average age was 61 years. (Fp)