Exercise When Sick

Guidelines

With athletes, it is well established that the ability to compete is reduced during sickness. Also, several case histories have shown that sudden and unexplained downturns in athletic performance can sometimes be traced to a recent bout of sickness. In some athletes, exercising when ill can lead to a severely debilitating state known as “postviral fatigue syndrome.” The symptoms can persist for several months and include weakness, inability to train hard, easy fatigability, frequent infections, and depression.

Concerning exercising when sick, most clinical authorities in the area of exercise immunology recommend the following:

• If one has common cold symptoms (e.g., runny nose and sore throat without fever or general body aches and pains), intensive exercise training may be safely resumed a few days after the resolution of symptoms.
• Mild to moderate exercise (e.g., walking) when sick with the common cold does not appear to be harmful. In 2 studies using nasal sprays of a rhinovirus leading to common cold symptoms, participants were able to engage in exercise during the course of the illness without any negative effects on severity of symptoms or performance capability. However, it should be cautioned that rhinoviruses account for only 40% of common colds, and further research is needed with other pathogens to determine their relationship to exercise.
• With symptoms of fever, extreme tiredness, muscle aches, and swollen lymph glands, 2 to 4 weeks should probably be allowed before resumption of intensive training.

For example, when one is sick with the flu, the safest approach is to avoid all exercise until the symptoms are completely gone. The individual should slowly return to a normal regimen of exercise and avoid pushing too hard too fast. Studies with animals show that intense exercise during the flu makes the illness more severe and long lasting. The individual should never attempt to sweat out a feverish illness with intense exercise. In the military, forced exercise by recruits who were very sick has led to some reported deaths. In animal studies, forced exercise during certain types of viral illnesses has caused damage to the heart muscle.

Whether one gets sick with a cold after a sufficient amount of the virus has entered the body depends on many factors. These include physical activity, nutrition, age, cigarette smoking, mental stress, and lack of sleep. Avoiding illness is the best strategy. Based on current understanding, individuals interested in maintaining immunity and decreasing the risk of getting sick should exercise moderately on most days of the week, eat a [Page 444]well-balanced diet, obtain adequate sleep, keep other life stresses to a minimum, avoid pushing too hard during training, and space vigorous workouts as far apart as possible.

Immune system function may be suppressed during periods of rapid weight loss, so when necessary, fitness enthusiasts and athletes should lose weight slowly. Cold viruses are spread by both personal contact and breathing the air near sick people. Therefore, if at all possible, athletes in particular should avoid being around sick people before and after important race events. Flu shots are recommended for all children and adults, but especially for older individuals or athletes who train heavily and compete during the flu season.

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