Exercise: Too Much of a Good Thing?
When it comes to exercise, I have the zealotry of the converted. As a kid, I faked asthma attacks to get out of the Presidential Physical Fitness Test, once missed my heat at a swim meet because I was in the locker room studying for a calculus test, and as a softball player, truly earned the nickname of Hardly Homerun Hobson. Then, in my early 20s, I discovered running, and soon you couldn't shut me up about the virtues of prolonged exercise. I started running marathons. When that got old, I took up triathlons and have now competed in several Ironman races. For years, I've insisted to everyone who questions whether 12 straight hours of exercise can possibly be good for me, that of course it is. How can it not be?
Except that sometimes, during the last 10K of a marathon, for instance, when I start bargaining with my quads like an atheist in a foxhole, I wonder whether that much e xercise can possibly be good. And a number of recent studies suggest that my exercise regimen could be doing damage to my heart, immune system, and the rest of my bod.
So I called Arthur Siegel, chief of internal medicine at the Harvard-affiliated McLean Hospital. For years, he has been studying nonelite Boston Marathon runners, and he runs the things, too, so I assumed he'd be a rabidly kindred spirit. He agrees that getting a moderate amount of exercise is one of the best things you can do for your health. Not so racing 26.2 miles. "Marathon running is an overdose of a good thing," he says.
That was not what I expected to hear. But Siegel has studied two phenomena that occur in marathonsnot commonly but enough to kill a handful of people every year. First is a heart attack. A few years ago, he tested 60 marathon runners before and after a race, looking at their heart rhythms and their blood for signs of damage that might indicate a heart attack. After the race, 40 percent showed enough evidence of blood markers to indicate heart damage, though the damage reversed itself within a few days. (The runners who trained the least had the most damage, suggesting proper conditioning is protective.)
Stressed out. The toll of running that long and that fast has a host of effects, including systemic inflammation and the promotion of blood clotting, both of which can lead to midrace heart attacks in people with some level of previously silent heart disease (and at a certain age, all of us probably have plaque in our vessels). "I'm not saying don't do it," he says. "It's a great way to expand your knowledge of yourself and test your limits. But if you're a middle-aged person at risk for coronary problems, you should probably do the training and skip the race."
Siegel has also studied hyponatremia, the potentially deadly condition that occurs when people in long endurance events (say marathoners who take more than four hours to finish or adventure racers) take in too much water or sports drinks. In its extreme cases, it can lead to brain swelling, seizures, and death.
Enthusiasm dampened somewhat, I consoled myself with the fact that I am not a middle-aged man and that in my last few big races I've gotten the hang of balancing my fluid intake. Like other racers, though, I've noticed that in the week following a big race I immediately come down with a bug. And last season, I seemed to have a chronic low-grade sore throat, mild fever, and fatiguenot to mention chronically crummy race results.
None of this is uncommon, I learned. David Nieman, in the department of health and exercise science at Appalachian State University, years ago abandoned marathons for working on his farm (and says he feels much better for making the switch). He says that while immunity goes up when you work out for less than about 90 minutes, after a marathon, runners are about six times as likely to get sick as folks who didn't race. The long-term consequences of this immune-system suppression aren't clear.
As for my fatigue last season, I was probably flirting with overtraining, I concluded after talking with Jack Raglin, who does research in kinesiology and sports psychology at Indiana University. This isn't the same as exercise addiction, where people take multiple classes a day at the gym and compulsively work out even when they're injured. Overtraining syndrome is defined by its symptoms: changes in mood, appetite, and sleep patterns, perhaps a series of colds or bugs, and a decline in performance. It's common in endurance sports like running or swimming or in other sports that require intense off-season conditioning. The more training you do, the worse it gets. (This sounds suspiciously familiar.) And the only way to break the cycle, Raglin says, is to rest.
I long ago reached the point of getting diminishing returns from my workouts. "I tell everyone to walk vigorously 30 minutes a day," says Paul Thompson, a cardiologist at Hartford Hospital in Connecticut. Researchers know that it's good for you; while exercise does raise the odds of a heart attack in that short time while you're working out, if you do it consistently, it drastically cuts your chances of heart problems over the long termnot to mention providing a host of other health benefits, from staving off obesity to preventing osteoporosis and possibly cancer. Quadrupling or quintupling Thompson's daily prescription isn't going to similarly increase my chances of better health and, if I'm not very careful, may put me at risk for other problems.
That said, there's no way I'm giving up my two-hour runs and six-hour bike rides. Some people climb mountains or meditate to achieve mental and emotional clarity or to cope with stress and other hazards of modern living. I run, bike, and swim long distances. Rather than drastically reducing my training, which would have the side effect of making me extremely unpleasant to be around, I've decided that I'll make a concerted effort to maintain balance in my life: to occasionally sleep in rather than head to the pool at 6 a.m., to spend an hour with friends or family for every one I spend on my bike, and to generally put my training in the larger perspective of my life. Of course, I will still try to kick ass in my next race.
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