Exercise-induced itching is a fairly common phenomenon, and the culprit is heat.

Explanation: Physical exertion creates heat in the hard-working muscles. This heat spreads, raising your internal temperature. The body needs to get rid of this extra core heat, so it sends more blood—which normally has a temperature of about 98.6º—to the relatively cooler skin, which is typically 80º to 90º. This excess heat makes the skin “think” that it is being injured. In self-defense, special skin cells release histamine, which in turn triggers itching, Dr. Schultz explained. Sweating exacerbates the problem because, even though perspiring is a body-cooling mechanism, the sweat itself further irritates the skin.

Though the itch can arise anywhere, it most often affects the face, scalp and neck. These areas contain a rich network of blood vessels and thus receive a lot of blood flow. In addition, your hair traps heat and increases sweating on the scalp. Contrary to what you may have heard, yeast on the skin is a not a factor in exercise-induced itching.

What helps: To minimize itching during workouts, try to keep your body relatively cool and dry while you’re exercising. For instance…

• Wear clothing that breathes and wicks away wetness. Good fabrics for workout wear include moisture-wicking synthetics and cotton/polyester blends (100% cotton breathes but won’t wick). Avoid 100% nylon, which traps moisture and restricts airflow.

• Wear a cooling neck wrap, following product instructions for chilling. Many such products are sold online for about $10 (for instance, at www.PolarBreezeBandanas.com).

• Keep a fresh towel handy to wipe away sweat before it has a chance to irritate skin.

• Lower the room temperature if possible—you’re less likely to itch in a cool room.

• Turn on a fan. The moving air helps to cool and dry your skin.

• If you exercise outdoors when it’s warm, shift your workout time to a cooler hour of the day.

• The more intense the workout, the itchier you are likely to feel—so consider reducing your exercise intensity.

• If the problem persists, try taking a nonsedating over-the-counter antihistamine, such as 60 mg of fexofenadine (Allegra), one hour before you work out. Dr. Schultz did not recommend putting a topical antihistamine on your skin.

For more info: See Dr. Schultz’s video at www.DermTV.com/prevent-exercise-itching.