Too much of a good thing?
High- calibre athletes may have ignored warning signs of health problems such as dizziness, breathlessness, extreme fatigue
When a high- profile athlete dies of a heart attack, couch potatoes everywhere feel a little less guilty about their sedentary ways. Can too much exercise be bad for you?
When a high- profile athlete dies of a heart attack, couch potatoes everywhere feel a little less guilty about their sedentary ways. After all, if the fittest of the fit can’t outrun heart disease, then what’s the motivation to put down the remote and get moving?
So when autopsy results for ultramarathoner ( and subject of the bestselling book Born to Run) Micah True showed evidence of heart disease, exercise naysayers had a bit more ammunition to back their belief that when it comes to increased longevity, the role of exercise is overstated.
It doesn’t help that True — who died in March — isn’t the only athlete who has recently made the headlines by collapsing during strenuous exercise. Professional soccer players Piermario Morosini and Fabrice Muamba both suffered heart attacks on the playing field this year. ( Morosini died; Muamba recovered.)
Then there are the perennial headlinemaking deaths of marathoners who have been felled by heart attacks during any of the numerous 42- kilometre races across the globe. They, too, are examples that exercise has a dark side.
So what is the truth? Is exercise the heart- healthy activity it’s made out to be, or is there a threshold where it morphs from being helpful to harmful?
“Exercise is good for your system,” assures Michel White, professor of medicine at University of Montreal and a cardiologist at the Montreal Heart Institute. “It’s protective [ against] heart disease and produces chronic changes to the heart muscle.”
Regular exercise strengthens the heart, making it work more efficiently. And in the case of athletes who regularly train at high volumes and intensity, exercise can actually enlarge the organ, which is casually referred to as an “athlete’s heart.”
Researchers estimate that about 15 per cent of exercisers have hearts that are larger and whose walls are thicker than average. White says the most significant changes in size occur among athletes who combine endurance and power, like cyclists and rowers, as opposed to athletes who rely on endurance only, like runners.
Usually the extra size, weight and thickness don’t result in any additional health risks. But recently several studies have suggested that endurance athletes who push their hearts too hard for too long can actually cause damage, which fortunately is reversible — provided the heart is given adequate time to rest and recover.
There have been suggestions that True, who was 58 when he died, was one of those athletes who taxed the heart beyond its capacity. Years of ultra- marathon races, combined with too little recovery, tipped the scales in the wrong direction.
And while True’s autopsy revealed that his heart was indeed oversized, the wall was thinner, not thicker, than normal. That, combined with mild dehydration and strenuous activity — he was out on a 19- kilometre training run — could have caused the heart to fail.
As for young athletes, like Morosini and Muamba, their deaths are more likely to occur due to undetected heart defects that have been present since birth. So, while vigorous exercise is the trigger, it’s not the actual cause of death.
As tragic as these deaths are, they are also quite rare. Stats are scarce, but a survey of Minnesota high schools reported sudden cardiac death occurred in one of 200,000 high school athletes a year.
The third kind of heart attack that makes headlines among exercisers is one that occurs during marathons. Typically, autopsies reveal these runners had coronary atherosclerosis, a form of heart disease that occurs in greater numbers among middle- aged and older men. Statistics also indicate that the majority of these heart attacks are fatal and occur within 1.6 kilometres of the finish line.
As to why the heart gives out during the marathon and not on any of the training workouts leading up to it, White suggests the high level of anxiety and excitement that surrounds the race — combined with the high physiological demand of running 42 kilometres - creates a unique set of circumstances that ramp up stress to the heart.
Does that mean middle- aged runners should avoid marathons?
Donald Redelmeier and Ari Greenwald, of the department of medicine at the University of Toronto, reviewed available statistics and determined the risk of sudden death during a marathon to be quite small. Their estimates suggest that a sudden death occurs with a frequency of 0.8 for every 100,000 exercisers — the equivalent of about two deaths per million hours of exercise.
They went on to compare those numbers to traffic fatalities, and found that for every marathoner who died from sudden cardiac death, almost two lives were saved from fatal crashes that would have otherwise occurred on the same streets during the same time interval on non- marathon days.
In other words, marathoners are safer running the streets than travelling them by car.
While it’s often stated that exerciserelated heart attacks occur suddenly and without warning, White says he’s convinced that in most cases warning signs were present but ignored. Symptoms like dizziness, extreme fatigue and breathlessness, or a gradual but persistent decline in performance, are signs that the heart is malfunctioning.
Unfortunately, most athletes mistakenly attribute such warning signs to more benign causes, like lack of sleep, a poorly timed meal or just an “off” day. White suggests that athletes listen to their body and seek medical attention should any such symptoms occur. He also warns distance athletes to remember that a healthy lifestyle isn’t defined by exercise alone. Learning to balance high- intensity, high- volume exercise with plenty of rest and a healthy diet is good for the heart, the mind and the body.