Senin, 04 Juni 2012

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

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

By Jenny Hope

PUBLISHED: 23:39 EST, 3 June 2012 | UPDATED: 23:39 EST, 3 June 2012


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.

Damage: Excessive endurance exercise can do long-term harm to the cardiovascular system, U.S. scientists say

Damage: Excessive endurance exercise can do long-term harm to the cardiovascular system, U.S. scientists say

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.’

Dangers: Too much physical exercise can cause musculoskeletal trauma and cardiovascular stress

Dangers: Too much physical exercise can cause musculoskeletal trauma and cardiovascular stress

A review published in the medical journal Mayo Clinic Proceedings (must credit) looked at studies detailing the mechanisms, pathophysiology, and clinical manifestations of cardiovascular injury from excessive endurance exercise.

Dr O’Keefe and colleagues said research suggests that extreme endurance training can cause transient structural cardiovascular changes and elevations of cardiac biomarkers, all of which return to normal within one week.

But for some individuals, over months and years of repetitive injury, this process can lead to the development of patchy scarring of certain areas of the heart, and abnormal heart rhythms.

In one study, approximately 12 per cent of apparently healthy marathon runners showed evidence for patchy myocardial scarring, and the coronary heart disease event rate during a two-year follow up was significantly higher in marathon runners than in runners not doing marathons.

The review said it had been known that elite -level athletes commonly develop abnormal electrocardiogram readings.

However, studies now show that changes to the heart triggered by excessive exercise can lead to rhythm abnormalities.

Endurance sports such as ultramarathon running or professional cycling have been associated with as much as a five-fold increase in the prevalence of atrial fibrillation, or abnormal heart rhythms.

Chronic excessive sustained exercise may also be associated with other heart problems including artery wall stiffening.

Dr O’Keefe said lifelong vigorous exercisers generally have lower death and disability rates compared with non-exercisers, but it was becoming important to detect intense exercisers whose regime might put them at risk.

The phenomenon has been dubbed Phidippides cardiomyopathy - after the fatal heart damage suffered by the original marathon runner.

Suffering: Massive physical efforts like those delivered by professional cyclist can be harmful, scientists say

Suffering: Massive physical efforts like those delivered by professional cyclist can be harmful, scientists say

The young Greek messenger in 490BC died suddenly after running 175 miles in two days, with the last leg of 26.2 miles from Marathon to Athens.

His death was the first report of a sudden cardiac death of a long distance runner.

Dr O’Keefe stressed the review findings should not undermine the message that physical exercise was good for most people.

He said ‘Physically active people are much healthier than their sedentary counterparts. Exercise is one of the most important things you need to do on a daily basis.

‘But what this paper points out is that a lot of people do not understand that the lion’s share of health benefits accrue at a relatively modest level.

‘Extreme exercise is not really conducive to great cardiovascular health. Beyond 30-60 minutes per day, you reach a point of diminishing returns’ he added.

Government guidelines recommend adults take aerobic exercise five times a week for 30 minutes or more for maximum he alth benefits.

Children should have at least 60 minutes of moderate to vigorous exercise a day, including taking part in sports, brisk walking and running.

Aerobic exercise is achieved through sports such as jogging, running, cycling, tennis and swimming.

The level of aerobic exertion should be enough to raise the heart rate to 120 beats a minute or higher, which includes a brisk walk and swimming. But taking a stroll or even gardening is also regarded as healthy activity.


 

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And lack of excercise and poor diet will cause a heart attack, right? ....You can never win. lol.

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It's "TOO" not "TO" ...

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Naturally too much wear and tear leads to damage. When use becomes abuse there is bound to be damage.

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He said ‘Physical exercise, though not a drug, possesses many traits of a powerful pharmacologic agent. and that powerfull agent is???? Anandamide LOL very old news Im afraid....

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Oh for goodness sake, just replace all the medical headlines with "life is out to end you"

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Interesting how nutrition isn't mentioned. Conventional wisdom tells you to load yourself up on carbohydrates in order to fuel your body. This invariably leads to high consumption of processed carbohydrates and energy drinks. The common denominator of these is sugar and sugar is the biggest inflammatory substance in our diet. This increased inflammation is then exacerbated by chronic cardio exercises such as long distance running and cycling with injury an almost inevitable outcome.

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I saw a stat published in a fitness mag that suggested athletes live shorter lives than average Joe does, by about nine years I think. Considering that includes the entire population of lard bellies it's quite a sobering thought! This research adds strength to that. A friend of mine is always doing triathlons, I think he does it to counter the beer he drinks! I've never known anyone to suffer from so many aches, pains and injuries. I'll carry on doing my 20 minute (body weight) sessions 4 times a week. After combining that with eating natural foods (meat, eggs, plenty of natural fat, fish, veg, fruit and nuts) I've lost over 4 stone and now maintain the perfect weight for my age/height effortlessly.

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Too much of anything is bad for you, duh . . . Stop trying to give lazy/fat people another excuse to throw up on their wall of 'reasons why I'm fat and it's ok'.

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I always theorized that the heart is a mechanical device and has a certain number of beats before it quits...the more you exercise the quicker you will reach that limit.

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The Olympic should come with a health warning: "TOO MUCH EXERCISE MAY KILL YOU"!

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