For those who get a rush from endurance sports, the deaths in 2007 were sobering.
In June last year, 17-year-old triathlete Thaddeus Cheong died from heart failure after he finished third in a selection trial for the South-east Asia Games.
Just two months later, Captain Ho Si Qiu, a 25-year-old platoon commander from the Singapore Armed Forces Officer Cadet School, died after completing a half-marathon.
Given the rising interest in endurance sports, and particularly, in the marathon, fitness enthusiasts should take care. Once considered a loopy stunt attempted by only a few weirdos, the marathon is now a rite of passage for many men, the coolest test out there of fitness and health.
While the benefits of regular exercise are clear, evidence has begun to mount lately that running the race may be anything but good for your health.
The physical effects of running a marathon, say researchers, include changes in the immune system and kidney function. But the main damage is done to the muscles, which leak injury-signalling enzymes into the blood.
The result is that the body's internal balance is deeply affected."Your body doesn't know whether you've run a marathon or been hit by a truck," says Dr Arthur Siegel, director of internal medicine at Harvard's McLean Hospital in the US.
And the heart is among the muscles subjected to this stress. After a marathon, the heart shows changes associated with heart attacks, according to a 2001 study by Dr Siegel and his colleagues.
Another study, done in 2006 and published in the journal, Circulation, showed that some marathon runners' hearts had trouble refilling chambers after a race.
Thankfully, there is good news from the Circulation study - proper training protects against heart injury during the race. Those who averaged at least 72km a week in training were significantly less likely to suffer heart damage than those who ran 56km a week or less.
The other good news is that the heart damage does not seem to be permanent, even among undertrained runners. All 60 marathon finishers in the Circulation study showed relatively normal cardiac function within a month.
But still, the relative risk of a heart attack increases during the race, even if proper training reduces your overall risk of heart trouble.
So runner be warned. Know the risks and prepare yourself properly before a marathon.
For the full story and running tips, get your copy of the December issue of Men's Health Singapore now.
