This time of year, you can throw a rock and hit somebody who’s sick. There’s coughing and sneezing everywhere! Additionally, this ‘home stretch of the year’ between Thanksgiving and New Years is probably the most stressful time of the year for all of us. It’s well-known that exercise can dissipate feelings of stress, help us to expend nervous energy, and keep muscles toned and hearts and bones strong. But what if we’re sick? Should we exercise anyway, or cool it for a while? I’d like to provide some general guidelines to this question this week.
If you have a temperature of 99.5 degrees Fahrenheit or above, don’t exercise. Body temperatures can rise to critical levels when working out with a fever, and you’re risking the development of heat stroke. (See a prior Insight for more information on the warning signs.) Fever is one of our body’s indicators that an infection is present; the internal ‘war’ of the immune system generates heat. Additionally, fever increases the body’s use of fluids, so the risk of dehydration and additional complications to the original illness also increase proportionately. At all times, and especially during times of illness, drink plenty of fluids before, during, and after exercise to avoid dehydration. Remember, too, that your body is ‘working overtime’ when you’re ill and have a fever. Combating illness demands calories, and your body is burning more calories than usual–even at rest. So, if you need to curtail your regular exercise regimen for a few days while you’re running a fever, don’t cut back on your calorie consumption to compensate. If you do, you’re only depriving your body of the calories needed to get you well, and up and on the run again.
Speaking of the runs, what if you have diarrhea and/or nausea and vomiting as your illness of choice? Once again, dehydration is quite possible from the illness alone. So, adding the sweating and fluid loss of exercise only compounds this phenomenon. Electrolyte imbalances and possible fatal arrhythmias of the heart can occur in such conditions. So, the bottom line on diarrhea. . .rest until it’s gone. . .no butts about it! If you know your usual resting pulse, it can provide a very helpful guideline to recovery. If your resting heart beat is ten beats per minute or more above normal, postpone your exercise until it’s back to your baseline. Your body will thank you, and you won’t look like a whimp with premature panting in your usual routines.
What if you have a cold but no fever? Recent research into the physiology of exercise has demonstrated that lung capacity of students infected with rhinovirus (the common cold virus) and healthy students was the same when they ran on a treadmill. In fact, the sick students reported that exercising didn’t feel any more strenuous than usual. Of course, one must remember that these were college students and therefore looking forward to the meager remuneration of such experiments–regardless of outcome!
What if your muscles hurt? Such symptoms are technically termed myalgias, and they indicate that your muscles are inflamed by the infection in your body. It’s not wise to irritate them further with exercise. Remember, one very important muscle in our bodies is the heart; it, too, can be inflamed by infections that attack/irritate muscle tissue. So, muscle up to the ibuprofen, aspirin, or acetaminophen instead. . .and wait it out–instead of weighting it out!
If you have a protracted cough and/or sputum production from your lungs as symptoms of your illness, you’re better off contemplating New Year’s resolutions and/or writing Christmas cards rather than working out to the Buns of Steel exercise video. Such symptoms are clear indicators that your airways are already infected/inflamed. . .and they don’t need the extra stress of huffing and puffing right now.
Though some studies show indicators of immune system depression with intense physical training, it’s not clear whether these changes are clinically important. Also, researchers point out that decreased immunity observed in some intensely training competitive athletes may be attributable more to the emotional stress of such training rather than the physical stress. At the very least, changes in one’s immune system with exercise are multifactorial, and probably not significant except at the highest levels of training.
One caveat to the above thinking. . .even if exercise does not increase susceptibility to illness by depressing our immune systems, it often makes us more sensitive to symptoms. Minor symptoms such as a stuffy nose and stopped up ears may seem minor to a couch potato but be quite annoying to a runner.
Ultimately, “listen to your body.” If you feel puny, you probably are. . .and your body knows best. It takes energy to heal your body from any illness, so a baseline fatigue or listlessness is a realistic barometer in this regard. Definitely, do not attempt a new activity, or a harder or longer workout when you’re not feeling well or immediately after resuming exercise. In general, wait at least one full week before such changes. You’ll decrease your risk of injuries significantly, and you’ll be better prepared physically for the additional challenges.
As a generality, if your symptoms are ‘above the neck’ such as stuffy nose, scratchy throat, watering eyes, and sneezing, then moderate activity may not be harmful. However, if symptoms occur below the neck such as coughing, fever, muscle aches or digestive symptoms, it’s best to postpone exercise and nurture your body. Remember, too, that your companion exercisers appreciate your absence when you come across as Typhoid Mary. They have their own holiday agendas. . .and don’t need to incubate your illness as an additional stress.
Stephen L. Hines, M.D.