Running is good for you, but not always good for your skin.
Developing a rash when you run can make you think twice about lacing up your shoes. Rashes can develop while running due to several causes, many of which are preventable if you take proper precautions when choosing clothing and getting ready to hit the road. Some rashes, however, can require medical intervention.
Causes of Rashes
Most rashes that occur during running develop because of friction -- your clothes rubbing against areas of bare skin -- or sweating. It doesn't take a great deal of friction to create a rash when running. A small seam that rubs your skin can cause hours of misery afterward. Clothes that are too tight or made from the wrong type of material can cause sweat to stick to your skin rather than wicking away from it. Wetness and friction create the perfect storm as far as rashes go. Running in the heat or running for longer durations increases sweating and your chances of developing a rash.
Choosing the Right Fabrics
Although cotton is soft and comfortable, it is a poor material for exercise clothing. Cotton doesn't breathe and absorbs moisture, so once it gets wet, it stays wet. Synthetic fabrics used for exercise clothing, on the other hand, wick moisture away from your skin, which lessens the chance of developing heat or chafing rashes from friction. Synthetic clothing can also help prevent jock itch, a fungal infection, by keeping the area dry.
Dressing for Success
Certain skin areas have a higher likelihood of developing a runner's rash, such as around the armpits, nipples on men, and the groin. For women, the underarms are prone to chafing because of bra rub. Look for sports bras with covered or flat seams. If your thighs rub together when you run, keep them separated by wearing long, tight-fitting compression shorts made of material such as Lycra or Spandex, which prevents skin-to-skin rubbing.
Lubricating or Covering Problem Areas
Lubrication helps prevent the friction and heat that cause rashes. You can lubricate with plain petroleum jelly or buy lubricators marketed especially for athletes. These come in a tube so you can roll the lubricant around your armpits, groin or buttocks before you leave for a run. Covering problematic areas with bandages can also prevent friction. For men, covering nipples with bandages or nipple guards during runs might be necessary.
Hives present a different problem than rashes caused by friction, although a rise in temperature can be the cause. Exercise-induced hives, medically termed cholinergic urticaria, occur in some people as they exercise. This type of hive can be related to a rise in temperature. Exercised-induced hives are small 1- to 4-millimeter itchy raised lesions. In some cases, systemic symptoms such as headache, wheezing or fainting can occur. Because of this, it is better not to run alone if you have this condition, DermNet NZ advises. Talk to your doctor if you develop hives while running.