Excess exercise 'hurts the heart' and cause dangerous long-term harm, say scientists

Extreme exercise such as marathons may permanently damage the heart and trigger rhythm abnormalities, warn researchers.
They say the safe ‘upper limit’ for heart health is a maximum of an hour a day - after which there is little benefit to the individual.
A review of research evidence by US physicians says intensive training schedules and extreme endurance competitions can cause long-term harm to people’s hearts.

Activities such as marathons, iron man distance triathlons, and very long distance bicycle races may cause structural changes to the heart and large arteries, leading to lasting injury.
Lead author Dr James O’Keefe, of Saint Luke’s Hospital of Kansas City, said exercise was generally beneficial for health but could tip into becoming harmful when taken to excessive lengths.

He said ‘Physical exercise, though not a drug, possesses many traits of a powerful pharmacologic agent.
A routine of daily physical activity can be highly effective for prevention and treatment of many diseases, including coronary heart disease, hypertension, heart failure, and obesity.

However, as with any pharmacologic agent, a safe upper dose limit potentially exists, beyond which the adverse effects of physical exercise, such as musculoskeletal trauma and cardiovascular stress, may outweigh its benefits.’

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