Runners deal with many common injuries and discomforts, and itching muscles is a commonly experienced but poorly understood complaint. This condition most often occurs in the legs. The multitude of possible causes is numerous, some environmental and others related to the runner's fitness and health.
The runner may experience the sensation of itching on the skin or underneath the skin. It may feel like the muscles themselves are itching, and scratching may or may not provide relief. Often the itching does not begin until you have exerted yourself. Itching can also occur after running.
Extremes in temperature can increase the likelihood of itching as the circulatory system must work harder to pump blood to warm the body. Blood is taken away from the muscles and pumped to the body's organs when it is cold. Therefore, your arms, hands, legs and feet may become colder than the rest of your body. This can lead to itching as the body warms back up and the blood comes back to the arms and legs. Exercise-induced vasculitis, another cause of itching, is more common in hot weather. Clothing, lotion or other irritants may also cause itching against the skin, since running produces friction.
One cause for itching while running is simply being undertrained. If you exercise less frequently or have a lower fitness level, there is more likelihood of this problem because your circulatory system may not have a trained response to intense exercise. As the capillaries expand to accept increased blood flow during exercise, an itchy sensation may result. Runners often report that once they improve their fitness levels, this sensation decreases.
When to Call Doctor
If you experience a rash, wheezing, nausea or diarrhea in addition to the itching, it is best to seek medical advice. Exercise-induced anaphylaxis is a rare condition that can cause itching and can lead to more severe problems. This is sometimes associated with intake of particular foods, where, in combination with exercise, an allergic reaction occurs. Exercise-induced urticaria refers to a milder allergic reaction including itching and hives.
Because there are so many possible causes of itching while running, it is important to figure out what is behind the itch. Warming up properly, easing into a running routine, and wearing weather-appropriate clothing can help prevent and relieve some forms of itching. If an allergy is suspected, your doctor may prescribe an antihistamine. For emergency situations, people who have exercise-induced anaphylaxis should carry epinephrine.