I haven't been seriously sick since early 2010, but right before the New Year my flu number came up. It started in the stomach. A day later, the head cold hit. The day after that, I awoke with a low fever and that groggy, achy, run-down feeling. "Shit," I thought. "This is just beginning."
It was during these early days of the flu—before the high fever and crazy chest cold clobbered me—that I had to choose: head to the gym to work out or skip it and stay home?
In high school, if I wasn't contagious, my swim coach swore that a tough practice in the pool would help—that I could, essentially, sweat it out. But my doctors have always called bullshit on this notion, their logic being: Your body is busy fighting something and you need to give it as much rest (and fluids) as possible.
Well, both are wrong.
First, working out super-hard for more than 90 minutes has been shown to weaken your immune system for up to two weeks, so that advanced Cross Fit class is out. Should you just ride the couch like the doc says, or can you do something less intense, like a short run?
Some respectable news outlets and health sites (the Mayo Clinic's included) and even the National Institute of Health love to cite this position paper, which says moderately working out when you have issues "above the neck," like a head cold or a mild fever, won't hurt you and may actually help, as opposed to "below the neck" symptoms like stomach aches or bronchitis. But there's one problem: This very legit paper is based on studies of elite, crazy-in-shape college athletes who work out an average of six days a week, not normal dudes in their late twenties and early thirties who hit the gym only a handful of times every week.
We non-athletes should brave a moderate sweat session, but only when the very first signs of the flu strike (a sniffle, a queasy stomach)—not when fever has set in. According to one study, getting up and moving around a little in the beginning may boost your immune system. It won't cure you, but it can ease your symptoms and shorten the duration of your sickness.
—Mike Dawson is a magazine writer and editor and a regular contributor to Details.
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