Filed under: Illness
Is it safe to exercise when I’m sick? This is a common question, especially from people who have strict workout schedules and aren’t likely to let the sniffles get in the way of their physical fitness. Benefits of exercise include weight control, improved mood, more energy, and better sleep. What’s more, just 30 minutes of regular exercise three or four times per week can boost your immune system and improve overall health, helping to keep those colds at bay.
Moderate exercise while you’re sick can be safe and in certain cases may actually improve symptoms (such as relieving congestion and increasing energy). But first you need to determine “how sick is sick.” You can figure this out by using the “neck rule.” If you have symptoms above the neck—including sore throat, nasal congestion, sneezing, or watery eyes—then moderate workouts can continue. If symptoms are below the neck—including cough, fever, fatigue, or body aches—then rest is in order until the symptoms are gone. You can also use your temperature to determine whether exercising is okay. If you have a temperature of 101°F or higher, moderate or vigorous exercise is not wise because of the risk of heat-related illnesses and dehydration.
Ultimately, the decision to exercise when you’re sick is up to you. If you’re too weak and fatigued to get out of bed, exercising may not be the best thing to do at that time. However, if you have symptoms of a cold and your temperature is below 101°F, light to moderate exercise may be beneficial. You should consider seeing a doctor if your symptoms don’t improve or get worse.
An important part of HPRC’s mission of fostering Warfighter resilience and optimizing Warfighter performance is informing you about the potential hazards associated with dietary supplements. But that’s a two-way street—we need your help too. An April 2014 article in The New England Journal of Medicine points out a major problem: Government agencies don’t get information about adverse effects of dietary supplements quickly enough from the public and healthcare professionals.
HPRC offers an easy way for you to directly report side effects you believe are associated with dietary supplements through the Natural Medicines Comprehensive Database (NMCD). Just go to our NMCD page and click on the icon for Natural Medicines Watch. You don’t even need an NMCD account; it’s free for everyone and easy to use. NMCD will make sure the information reaches FDA’s MedWatch.
Don’t hesitate to report something—you’ll be helping others avoid potentially serious health problems. Not sure about your symptoms? Read HPRC’s article about how to know if you’ve had an adverse event.
Performing physical activity—whether exercise or mission demands—at moderate (4,000–7,900 ft or 1,200–2,400 m) and high (7,900–13,000 ft or 2,400–4,000 m) altitudes can be challenging. At high altitude, oxygen pressure is lower, which results in less oxygen in the blood and muscle tissues. And as altitude increases, there’s a decrease in air temperature (about 2°F for every 500 ft or 150 m), less moisture (resulting in drier air), and increased solar radiation. Use sunscreen, drink plenty of water, and watch out for the signs of acute mountain sickness: headache, nausea, shortness of breath, and impaired cognition and balance.
To learn more about altitude sickness, read the article “The Invisible Enemy of the Afghanistan Mountains” on the United States Army Research Institute of Environmental Medicine (USARIEM) website. And learn more about performance at altitude in the Altitude section of HPRC's Environment domain.
With current and future military operations in mountainous regions, the issue of acute mountain sickness (AMS) is a significant medical concern. AMS can affect anyone, military or civilian, who is unacclimatized and/or ascends too rapidly to high altitudes. Symptoms of AMS can include headache, nausea, fatigue, dizziness, and sleep disturbances. Recently, researchers at USARIEM were able to predict the severity and prevalence of AMS after rapid ascent to various altitudes. What they found was that for every thousand-meter increase in elevation over 2,000 m, a person was over four times more likely to develop AMS. In addition, the severity of sickness doubled, and the odds that the AMS would worsen increased almost five-fold. AMS appeared to peak at 18 to 22 hours of exposure to altitude and then went away after 42 to 48 hours. The severity of sickness is greatest above 4,000 meters and may require evacuation to lower altitude or immediate medical attention. It also appears that men are more likely than women to get AMS and more likely for it to be severe. For both men and women, the more active they were at altitude, the longer it took to recover. These findings support current recommendation to limit activity as much as possible in the first 24 hours at altitude to decrease the risk for AMS.
This information should help military leaders manage and perhaps prevent AMS among troops by knowing the elevation, types of activities, and lengths of stay at altitudes.
In order to reduce the risk for AMS, acclimate to moderate elevations (2,000 – 3,000 m) if/when possible. In addition, stay hydrated and try to limit your physical activity at altitude for the first 24 hours. Read more about the effects of altitude on performance and how to minimize your risk for AMS.
It's true that exercise can help prevent the common cold by strengthening your immune system, but you should be cautious if you are considering an intense workout when you do fall sick. Some recommendations from the American College of Sports Medicine (ACSM) are to:
- Exercise moderately when the cold symptoms are confined to your head,
- Stay in bed if illness spreads beyond your head - don’t “sweat out” your illness, and
- Resume your exercise program slowly as you recover.
Check out ACSM’s guide, Clearing the Air on Exercise and the Common Cold for more information.
An article published in ScienceDaily reports on a study which shows that regular exercisers are less likely to fall sick with a cold or flu. The study participants who exercised more were less likely to report a cold or flu in the fall and winter seasons, and if they did get sick, they had fewer symptoms with shorter duration. Click here for more information on this study.