Itchy legs are a common experience for runners.
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If you've experienced itchy legs and redness while running at some time -- usually when first starting a running program or after returning from a rest period from regular running -- you're not alone. This is your body's natural response to the increased blood flow demanded during cardiovascular exercise, which expands blood vessels that have grown smaller during times of less activity. Extreme temperatures, skin irritants and failure to warm up and cool down before and after running can also cause itchy legs.
Expanding Blood Vessels
Itching is often felt during running because it is an intense cardio exercise that increases blood flow to up to 15 to 20 times greater than during resting. This dramatic blood flow increase also greatly expands blood vessels, causing them to impact nerves in skin, which then trigger a need-to-itch response from the brain. Often, this also causes the skin to turn pink or red. With regular running and improved fitness, the blood vessels will remain in a more expanded size, and this type of itchiness will decrease.
The Weather Outside is Frightful
In extreme cold temperatures, your extremities will be cold at the beginning of your run as your body pumps more blood to your internal organs to preserve heat. Even if you are in good shape, once you begin running and your legs and arms warm up, the increased blood flow that results can cause itching. If itching in cold weather is too much to cope with, try running indoors, warming up indoors before going outside or investing in high-quality cold weather running pants and long shirts.
When Something Rubs You the Wrong Way
Your itching could be caused by something irritating your skin, such as the constant rubbing during running of tight clothing or fabric. Try wearing loose-fitting, natural-fiber running pants or shorts to alleviate this type of itching. Your itching could also be caused by body lotion or other bath products that trigger an allergic reaction from the increased heat and rubbing on the skin caused by running. Hypoallergenic bath products can alleviate itching from lotions or soaps that are causing irritation. See your doctor if you experience the signs of a serious allergic reaction, which include a rash, nausea or shortness of breath.
The Importance of Warming Up
Itchy legs are often the price you pay for skipping a warm-up before running. At the start of exercise, muscles demand increased blood flow, which is routed from the skin and internal organs. Once the muscles are fully warmed up and pumping, they return blood flow outward to the skin. This process causes a dramatic expansion of the skin's blood vessels as they first contract to provide blood to the muscles and then expand to receive blood once the muscles are warmed up. Stretching and walking before running activates muscles and allows blood vessels to expand gradually. This eliminates the shock to your nerves of rapidly contracted and then expanded blood vessels that happens when you take your body from zero to top speed in less than a minute.