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Sheryl Kraft

Sheryl Kraft, a freelance writer and breast cancer survivor, was born in Long Beach, New York. She currently lives in Connecticut with her husband Alan and dog Chloe, where her nest is empty of her two sons Jonathan. Sheryl writes articles and essays on breast cancer and contributes to a variety of publications and websites where she writes on general health and wellness issues. She earned her MFA in writing from Sarah Lawrence College in 2005.

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Exercise and Immunity: What's the Connection?

Nutrition & Movement

My children used to laugh at me when I gave them my best advice for treating a cold.

Go exercise, I'd insist. Works like a charm!

They'd look at me with blank stares, pick up their tissues and walk away.

But now they're in their 20s. And if you have older kids, you know what happens. Eventually they start to listen. Now when they have colds, they take their tissues along to the gym.

READ MORE: Is It OK to Exercise With a Cold?

Granted, a cold may be severe enough to deplete you of any available energy. You may just want to keep your miserable body safe and warm under the covers. And naturally, to put yourself around people when you're spewing germs is inconsiderate and just not wise.

But, if you're feeling up to it—and your symptoms are all "above the neck" (meaning a case of the sniffles, a stuffy nose, sneezing or scratchy throat)—exercise may actually do you some good.

Exercise can not only make you feel better when you have a cold by opening up your nasal passages and relieving congestion, but it can also boost your immune system by fighting off simple bacterial and viral infections. And, as is common knowledge, it can also decrease your chances of developing heart disease, osteoporosis and cancer.

Although experts don't know the exact mechanisms behind exercise's magic in increasing your immunity to several illnesses, some theories are out there:

  • It helps by flushing bacteria out of the lungs, thus decreasing your chances of catching a cold, flu or other airborne illness.
  • It may flush out cancer-causing cells (or carcinogens) by increasing the output of wastes (like urine and sweat).
  • It speeds the rate of antibodies and white blood cells circulating through your body. While circulating more rapidly, these defense cells could detect illnesses earlier than they might have done normally.
  • It increases the rate of circulating blood, which may also trigger valuable hormones that send a warning to your immune cells that says, "Danger ahead! Be on the lookout out for nasty bacteria or viruses!"
  • It temporarily raises your body temperature, which may prevent bacterial growth, allowing the body to fight infection more effectively—similar to what happens when you have a fever.
  • It slows the release of stress-related hormones. And when you're in a state of stress, your immune system is suppressed, thus making you more vulnerable to illness.

READ MORE: Natural Ways to Prevent and Manage the Flu

If you're feeling a bit under the weather and willing to exercise, it's likely you'll have to pare down your normal routine. I learned that recently when I returned to the gym after almost a week's absence. I had to decrease the speed, intensity and length of my workout considerably. But I'm happy to report that after a few days, I was able to work back up to my normal routine.

And if you are motivated to use exercise as a way to boost your immunity and not get sick in the first place, be cautious: more is not necessarily better. Studies have shown that heavy, long-term exercise (like marathon running and intense gym training) could actually have the opposite effect and decrease the number of disease-fighting white cells and increase those unwanted stress-related hormones.

READ MORE: More Reasons to Love Exercise

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