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Monday, March 26, 2007

Exercise and cancer - is too much exercise bad for you?

"She won the New York City Marathon from 1978-80, 1982-86 and 1988, the London Marathon twice (1983, 1986), was world marathon champion in 1983, a five-time world cross-country champion and won silver in the marathon at the 1984 Olympics.
So now Waitz has been diagnosed with cancer. Not too different than Lance Armstrong, one of the most talented endurance athletes of all time who came down with testicular cancer.
Exercise is absolutely necessary for high-level wellness, but if you exercise too much it is clearly harmful and cancer seems to be a possible adverse outcome. My guess is that one's antioxidant threshold is exceeded or micronutrients are consumed at a level that cannot be easily replaced. Either way, they both add up to a major problem."

Quoted from an article by Dr J Mercola in response to the news that runner, Grete Waitz, is undergoing treatment for an unspecified form of cancer.
Gary Moller comments:
While much disease is still "luck of the draw", there is still a lot that we can do to reduce controllable risk factors so that the odds of the draw are more in our favour. Too much exercise is not good for us. Having spent most of my life in sporting circles I have been well aware that exercise does not necessarily make one healthier.

Longterm studies such as the Framingham Study, show that moderate exercise improves life expectancy; whereas excessive exercise reduces it. Excessive, exhaustive exercise can deplete immune function and increase the risk of colds (This can be countered to some extent by taking additional antioxidants, principally vitamin C) Please refer to my earlier article about this.

The first defense against disease, including cancer, is a strong immune system that is bolstered by dietary antioxidants derived from foods such as berries and brightly coloured fruit and vegetables. Adequate vitamin D derived mostly from sunlight is essential for a robust immune system.

We need to reduce exposure to toxins such as environmental pollutants and numerous chemicals in products like cleaners; burned, stale and rancid foods, food additives and even excess alcohol and various medications. As sports people we should not ignore the cancer risks of anabolic steroid abuse which is popularised by high profile athletes and celebrities (Refer my article about Arnold Schwarzeneggar).

One of the best predictors of future ill-health is stress and that includes events like getting married, divorced, changing jobs, a promotion/demotion, travel and running a marathon. We sure can do a lot about exercise; but what about the people who overdo it and do so year after year?

As many doctors know, an obsessive-compulsive addiction to exercise is one of the most difficult sports medicine problems to deal with. There are numerous examples of compulsive exercisers who continue to exercise to excess, despite badly worn joints. A doctor's advice to "rest up" is seldom heeded.
Refer to my earlier article about excessive exercise here. In such cases, a combination of referral to counselling services and being placed under the caring wing of a knowledgeable sports coach may be the best course of action.

While exercise is good for you, too much of a good thing is not. Maintaining good health is all about balance in life and moderation of all things good while minimising all things bad.


Ridodirected said...

Thanks for the article about "Exercise and cancer - is too much exercise bad for you?". I read your artile and it makes more guilty now because I am also a marathon runner and I do too much exercise during weekend. Thanks for giving me the idea

Gary Moller said...

Please do not feel guilty - this is not good for you!

Edward Sargisson said...

Goodness - it'd be nice if Dr Mercola provided some evidence. He went from one great marathoner getting cancer, included a great cyclist who got cancer before he was a great cyclist and concluded, "but if you exercise too much it is clearly harmful and cancer seems to be a possible adverse outcome."

That's a sample size of precisely 2 and not even random. Sounds like the black swan syndrome to me (you never expect to see black swan until you see one - and then you expect to see them everywhere).

Overtraining is an identified condition but I'd like to see some evidence before claiming it causes cancer.

Gary Moller said...

At ease Sarge!

Yes, a sample of just 2 is not much at all; I think he was just using a couple of high profile examples to show illustrate that super athletes are not bullet-proof.

We can not ignore the ample research that shows extreme exercise habits decreases life expectancy whereas moderate exercise improves it.

There are many examples I know of very fit people dying prematurely or falling seriously ill from all number of ailments that are similarly suffered by the general populace. There are higher rates of melanoma among distance runners and triathletes, I wonder about the prevalence of nervous system diseases like Parkinsons among athletes and even the fittest aerobic athlete has been known to drop dead. I have written several articles and e-pub about sudden death among the seriously fit.

You are right to challenge that it may not be the overtraining as Mercola suggests. Too much sun, eating all the wrong foods, not looking while crossing the road, riding a bike at speed in Wellington, not going to the doctor and so on and so on. It may be as much to do with lifestyle and attitude and the fact that many excessive exercisers are obsessive compulsive types who are headed for an early grave no matter what!

I think the message remains unchallenged: all things in moderation. Incidentally, some people would accuse me of ignorinhg this message by being excessive when it comes to the exercise thing! There will be more to say about this matter later.

Wayne said...

compared to other top athletes waitz didnt train that much, she hated long training runs. and prefered shorter faster workouts, she didnt run much over 100k a week on a heavy week, most top athletes would train more than her, there could be an argument of is intense exercise worse for you than lower intensity exercise because it generates far more toxins in the body that need to be dealt with. arthur lydiard ran phenomenal miles running up to 300km a week, he didnt eat a spsecial diet if anythingg by the standards of todays athletes it was sub standard yet he didnt die of cancer, there are so many factors that cause cancer not related to exercise you cant point the finger at exercise as teh main cause, research by Dr Peter Snell shows that in general and within reason the more intensely elderly people exercise the better it is for their health. cancer can also be caused by environmental toxins, genetic faults, poor diet, poor lifestyle choices, excessive stress. infectious deiseases.
how do you prove intense exercise contributes to cancer and degenerative diseases decades later? possibly it does, but more sound scientific evidence has to be presented than jsut a few famous people getting degenerative diseases, one in three people will be seriously affected by cancer and a significant number of those will die from it. so at least one third of well known athletes are likely to be part of those statistics. At some point we have to stop all this supposition, Healthy options magazine posted a cover on ruapehu erupting coinciding with nuclear testing in Mururoa, if they had have consulted VUlcanologists they would have been told there was a zero percent chance of the two being linked rather than scare mongering with supposition, this is a debate and there isnt enough evidence presented to be conclusive on the verdict. waitz didnt even race that much, its just that she tended to win just about every big event she raced by modern standards she hardly raced at all,
Anne Audain had a far more prolific record of racing than grete waitz and she probably trained harder, i havent heard of her getting cancer, Lorraine moller and Alison Roe are of the same vintage as well as Waitz, no word of them getting cancer but the odds are one of them will get cancer becaues of the statistics i mentioned above

Wayne said...

we can go back even further in history, how many of lydiards athletes have had cancer. one that i know of of half a dozen vrey famous athletes and they all trained harder than waitsz runnign up to over 200k a week without special diets and again by todays athletes standards a sub standard diet for a high performance athlete

Gary Moller said...

I continue to agree with Sarge and Wayne about the lack of evidence of a direct link, but we can not ignore that intense exercise may reduce overall life expectancy. As to cause, these are many ranging from accidents to melanoma to heart attack - and just plain wearing out prematurely. There may also be an association with the kinds of personalities that excessively exercise - driven types and obsessive-compulsives of this world who would be doing something else to excess if it was not exercise!

We know that intense exercise floods the body with massive amounts of free radicals (and Grete Waitz sure did a lot of that over an extended period of time)and we know that free radicals damage DNA unless quickly neutralised. Doesn't look too good to me!

Wayne said...

compared to other athletes, i dont think waitz did that much more than most, Lorraine Moller was at the height of her powers around that time and she had a far longer career than waitz. Anne Audain was racing constantly for years. there are stories of athltes who tarained far more, Lydiard would run up to 300km a week, plenty of athletes would clock up 200km a week for years and have gotten through without debilitating medical conditions, although most were generaly worse for wear through injury and illness