Exercise And The Common Cold

winter-runningSome things never come our way, no matter how hard we try. Wouldn’t it be really cool if you could win the trillion dollar lottery at least once? Or maybe twice? On the other hand, some things do come to us without trying, like the in-laws at holiday time, the IRS in April, and the common cold, also known as coryza. If you’re an adult—and if you’re reading this you probably are—you’ll get about two to four such viral infections a year. Your kids will get more than a half dozen. Then, again, you might be one of the fortunate few who get none. Collectively, colds, the flu and other upper respiratory infections are classed as influenza-like illnesses.

Some science people hold that viruses are not actually living things because they cannot reproduce on their own. They can’t go through cell division because they are acellular, not made of cells. That means they have to use your cellular material to make copies of themselves, and that means they have to get inside one of your cells, where they disguise themselves as part of the gang.  That’s when they start to sneak around, fooling other cells to accept them as friends, and then cloning themselves repeatedly. If your immune system is awake and on the job, it’ll recognize this fraud and take steps to halt it.  If it isn’t, you’ll get sick for as long a time as it takes to recoup your resources.

The rhinovirus is the most studied of the pathogens that cause upper respiratory infections (URI).  There are more than a hundred, and are most infectious in the first three days after the onset of symptoms. One of the things that separate a cold from the flu is that cold symptoms show up a couple of days after infection; with the flu, it’ll be sudden onset with extreme fatigue.  (Eccles. 2005)  Exposure to the cold weather has little to do with catching a cold, although it might compromise the immune system. Staying indoors and being in close proximity to other people is a more likely cause. All you have to do is to touch a doorknob turned by a sneeze-covered hand, or to breathe in the particles that already erupted from somebody’s nose or throat, and bingo, you’ve got it. Makes you want to stay home, doesn’t it?

There is not one thing on the market that can get rid of a cold. Nada. Nothing. Zip. You might be able to control symptoms, though, and for most of us, that’s enough. Vapor rubs for the chest, antihistamines for the runny nose, analgesics for physical discomfort, and chicken soup for the soul, which, by the way, might just be the last word in cold medicine. It’s kind of frustrating to find out that medical books don’t really address colds (at more than a few hundred dollars each), but that granny does. (Ibid.)

Whatever you do, don’t ask for an antibiotic. You can’t kill things that aren’t alive in the first place, but you can disrupt the whole immune system machinery and get the nasty side effects.  If you really and truly want to do something about your cold, exercise it away. Sounds goofy, especially because you don’t feel like it.

People who exercise seem to have fewer and milder colds, says a report from the Appalachian State University in North Carolina. Dr. David Nieman and colleagues collected data from more than a thousand subjects, ages 18 to 85, and tracked the number of URI’s they suffered.  Among the data were reports of the kinds and frequency of exercise, personal fitness evaluations, and dietary habits and lifestyle. It was found that those who exercised five or more days a week experienced 41% fewer days’ worth of cold symptoms. Also, colds were milder for those in better shape than for those who were sedentary. Dr. Nieman explained that exercise mobilizes the immune system at a higher rate than normal and causes immune cells to attack viruses. (Nieman. 2011)

As opposed to intense, strenuous workouts, moderate exercise reduces the number and severity of colds. Prolonged strenuous exercise opens a window for viral attack by exhausting the first responders of the immune system. Investigators at the Department of Exercise Science of the University of South Carolina learned of increased susceptibility to respiratory viral attack following exercise stress in lab animals that ran a treadmill to the point of fatigue. The animals subjected to such rigors were more likely to succumb to administered viruses than those that rested or were less taxed.  (Murphy. 2008)

When a geriatric populace was examined under the hypothesis that moderate exercise could promote resistance to upper respiratory tract infections, Polish researchers found that, not only was susceptibility to infection reduced, but also that symptoms of depression were ameliorated. In this cohort, there was a distinct negative association between physical activity and sickness.  (Kostka. 2007)

T-cells are a major source of messenger cytokines responsible for the biological effects of the immune system. They have antigen-specific receptors on their cell surfaces to allow them to identify invaders. Th1 cytokines produce the pro-inflammatory response that kills intracellular parasites and perpetuates autoimmune responses. Interferon gamma is the star player. If this gets out of hand, there can be excessive tissue damage, so there is a balancing mechanism in Th2 cytokines, which include interleukins 4, 5, and 13. These promote the IgE responses that are common to skin and mucus membranes. Interleukin 10, also a Th2, is seriously anti-inflammatory.  In the best case scenario, Th1 and Th2 will be balanced at the exact ratio needed to face an immune challenge. It was discovered at the University of Illinois that moderate exercise (pay attention to the word “moderate”) would shift immune response from the pro-inflammatory Th1 to the anti-inflammatory Th2 cytokines, thereby reducing lung pathology and influenza protein expression, thus improving survival after virus infection. (Lowder. 2006)

Current study is examining nutritional supplements as countermeasures to exercise-induced immune changes and infection risk.  Quercetin, beta-glucan, and curcumin are cited as being able to reduce the magnitude of such immune system insult and resultant risk of URI.  (Nieman.  2008)

Now we have another reason to get up from the couch and leave the remote behind.

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Lowder T, Padgett DA, Woods JA. Moderate exercise early after influenza virus infection reduces the Th1 inflammatory response in lungs of mice. Exerc Immunol Rev. 2006;12:97-111.

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Murphy EA, Davis JM, Carmichael MD, Gangemi JD, Ghaffar A, Mayer EP. Exercise stress increases susceptibility to influenza infection. Brain Behav Immun. 2008 Nov;22(8):1152-5. Epub 2008 Jun 21.

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David C Nieman, Dru A Henson, Melanie D Austin, Wei Sha Upper respiratory tract infection is reduced in physically fit and active adults Br J Sports Med. 2011 Sep;45(12):987-92. Epub 2010 Nov 1.

Woods JA, Keylock KT, Lowder T, Vieira VJ, Zelkovich W, Dumich S, Colantuano K, Lyons K, Leifheit K, Cook M, Chapman-Novakofski K, McAuley E. Cardiovascular exercise training extends influenza vaccine seroprotection in sedentary older adults: the immune function intervention trial. J Am Geriatr Soc. 2009 Dec;57(12):2183-91.

Wright PA, Innes KE, Alton J, Bovbjerg VE, Owens JE. A pilot study of qigong practice and upper respiratory illness in elite swimmers. Am J Chin Med. 2011;39(3):461-75.

*These statements have not been evaluated by the FDA. These products are not intended to treat, diagnose, cure, or prevent any disease.