Too Much of a Good Thing

By Jim McVeagh 19/06/2010

Until this morning, I did not know who Peter Snell was. I was, therefore, somewhat surprised to see a large front page spread in the Weekend Herald getting all excited about a 71-year-old man having heart disease. It seemed to me to be somewhat reminiscent of the famous “cat stuck in tree” line. I was only slightly enlightened to see that this was yet another famous New Zealander I have never heard of. This is no reflection on the achievements of Mr. Snell. The MacDoctor is notoriously bad at remembering sports celebrities due to his almost militant lack of interest in sport of any shape or form. Regular readers will no doubt have noticed the dearth of sports-related posts on MacDoctor.

I am only vaguely aware that South Africa, in which I lived for more than 20 years, is hosting the soccer world cup. Apparently, New Zealand drew their first game and this is somehow a good thing? I thought the plan was to score more goals than your opponent, but clearly I know nothing.

Back to Peter Snell and his dicky heart. While it is no surprise to me that a 71-year-old man has heart disease, it is even less of a surprise that a competitive athlete has serious heart disease. I clearly recall a study done in South Africa 20 years ago in which the investigators took blood from Comrades marathon runners after the event (the Comrades marathon is a 90km ultra-marathon run between Durban and Pietermaritzburg every year). Every participant in the small study had significantly elevated heart enzymes – the same ones we use to diagnose heart attacks. It is thought that this was caused by diffuse hypoxic damage (heart cells dying from lack of oxygen all over the heart). Call me chicken if you like, but that news extinguished any desire to do any long-distance running. Admittedly, there wasn’t a great deal of desire there in the first place.

That early South African study has been backed up many times. There is little doubt that athletes who train intensely are at increased risk of sudden cardiac death immediately after their training (I cite only one article here, there are plenty of others). There is also some evidence that the increased amount of oxidative stress (free radical production) caused by intensive exercise does cause long-term damage to the arteries, resulting in additional plaque formation (I am not aware of any particular definitive study on this, though).

Moderate exercise is good for you. The body apparently easily copes with the additional oxidative stress, producing higher levels of anti-oxidants. These higher levels of anti-oxidants are then useful for mopping up the extra free radicals we produce from eating junk and being generally stressed out of our minds. At least, that’s the theory. But competition-level athletes pay a price for their extreme conditioning, both in physical form, with injuries, and in physiological form with potential heart damage (and possible other organ damage – particularly kidneys).

Once again the old adage is true – too much of a good thing is bad for you.


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