*Exertion during illness will likely make you sicker. The solution: Take a
By Jeannine Stein
September 14, 2009
Far be it for die-hard fitness buffs to let a little fever stop them from
doing their regular workout -- or for driven Pop Warner football players to
miss a practice. But it's not actually laudable to laugh in the face of an
illness such as the H1N1 virus.
"The best information we have says complete bed rest is best," says David
Nieman, director of the human performance lab at Appalachian State
University in Boone, N.C. And forget the idea you can sweat out the flu
through intense exercise: "That's a myth," he says. "A *big* myth."
Working out, especially at a vigorous pace for a long stretch, may do more
harm than good.
"We know that heavy exertion causes a transient downturn in immune function
that can last from a few hours to a day," says Nieman, a professor of health
and exercise science. During heavy, prolonged physical exertion, he adds,
stress hormone levels such as cortisol rise, causing immune cells to
function less efficiently. "During this downturn, if you have a virus, it
will multiply at a higher rate and make you sick."
In research published in the journals Sports Medicine and Medicine & Science
in Sports & Exercise, Nieman has found that immune function is compromised
among marathoners after a long race. They're simply not as effective as
people who haven't overexerted themselves at fighting off invading viruses.
Although much of the data in the area of exercise and viruses have been done
on animals, Nieman says even those show that -- when dealing with a systemic
virus with symptoms of general fatigue, aches and pains -- rest is necessary. "If any level of exercise is engaged in," he says, "you risk making the illness more severe."
*The fever factor*
Raising body temperature may be chancy as well, he adds. "It makes
physiological sense. If your core temperature is already up and you dare to
add to it, you have to keep in mind that viruses like to multiply with
higher body temperatures. Everything is multi-factorial, and that may be one
Common sense is always a good rule to follow when it comes to being sick,
but not everyone subscribes to that. Nieman says he was training for a
marathon when he got a mild flu. The day after his fever broke, he ran, only to be slammed with symptoms again. "I completely relapsed," he says. "It was
dumb. I knew all this stuff, but that's what drives a lot of athletes, that
need to get back into the race."
Dr. Peter Katona isn't completely anti-exercise for those who may be dealing
with a virus but cautions regular exercisers to heed what their bodies are
telling them. "If you feel up to it, you can do some light working out, like
stretching," says the associate professor of clinical medicine at UCLA who
specializes in infectious diseases. "Do things that aren't going to give you
a lot of sweat and fatigue. Don't push yourself, but let your body be your
guide." And stay home -- don't go to the gym to exercise and spread the
The article goes on to talk about the possible benefits of exercise on the
immune system when not sick.
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