Why You Get 'Runner's Itch' During Cardio Workouts

Find out the common causes behind runner's itch and who's most likely to feel the urge to scratch halfway through a sweaty workout.

Embarking on your initial high-intensity jog after a long hiatus, you anticipate encountering several less than comfortable physiological reactions: Sweat dripping in your eyes, trembling muscles in your legs, or perhaps a sensation of breathlessness. However, one unexpected side effect might be profoundly itchy legs. This peculiar condition is commonly referred to as runner's itch, and many people experience it. In the following discourse, a physical therapist provides insight into why one feels an intense itching sensation during a run. Furthermore, suggestions on treating and preventing runner's itch are discussed.

Runner's Itch Causes

While the term 'runner's itch' might suggest a condition exclusive to runners, it is in fact a reaction that can be triggered by any form of intense exercise, according to Rena Eleázar, a New York-based Certified Specialist in Sports Physical Therapy and co-founder of Match Fit Performance. This happens because your muscles need more oxygen when you're working out, leading to dilation of blood vessels to facilitate increased blood supply. This dilation results in swelling of capillaries and arteries, activating certain nerve endings that cause the itching sensation, explains Eleázar. Another factor contributing to 'runner's itch' is the release of histamine - a chemical typically released in response to allergens. Notably, research suggests that histamine secretion may also occur during aerobic exercises, adds Eleázar. "When you work out, it triggers your sympathetic nervous system, leading to release of histamine to inhibit fatigue," she elucidates. Histamine further causes dilation of blood vessels, explaining why one might feel intensely itchy post a sprinting session, shares Eleázar. Additionally, skin sensitivities could exacerbate the feelings of itchiness. Allergic reactions to detergents or irritation from sweat droplets on skin or perspiration-soaked clothing can enhance itchiness. If you're already experiencing 'runner's itch', such factors might intensify your symptoms, warns Eleázar.

Runner's Itch Symptoms

Runner's itch most commonly develops on the lower torso and legs — an area to which blood rushes when you're sprinting — though it can occur anywhere on the body, says Eleázar. Along with itchiness, you may also develop redness or a feeling of warmth in the affected areas, but these symptoms will gradually go away once your blood flow returns to a resting level, she adds. And currently, there aren't any known long-term health risks associated with runner's itch, she adds.

Who Is at Risk for Developing Runner's Itch

If you have recently joined a High-Intensity Interval Training (HIIT) session or sprinted on a treadmill, rest assured runner's itch is not necessarily in your future, as noted by fitness expert Eleázar. "This condition does not affect everyone," she clarifies. However, those who've been leading a relatively inactive lifestyle may be more susceptible. "Runner's itch mostly occurs in individuals who have been less active," explains Eleázar. "Their bodies aren’t accustomed to the sudden increase in blood flow nor the need for capillary expansion to accommodate the high demand of blood in the muscles, especially during strenuous activities like running. It practically sends their body into a state of shock." For instance, individuals who have recently taken up running or those who return to it after a significant break and rush into high-intensity sessions may experience this unbearable urge to scratch.

How to Treat Runner's Itch

If a strong itch is preventing you from enjoying your run, the ideal way to mitigate this sensation is by reducing your workout intensity (for instance, walk instead of jog) or even halting your exercise routine completely, suggests Eleázar. "The itching is triggered by the body's need for increased blood circulation in the area, so if you decrease the demand for intensified blood flow to your lower limbs and possibly your arms, it will typically diminish," she explains. If the urge to scratch persists, applying an anti-itch cream can also bring relief, she adds. However, if your symptoms persist beyond a few hours, or if you're regularly experiencing runner's itch (for example, after every workout), Eleázar advocates that you consult with a healthcare professional to identify the underlying cause of your itchiness and receive appropriate treatment.

How to Prevent Runner's Itch

In order to avoid the discomfort of runner's itch, it's crucial that you take certain preventative measures. One such step involves wearing garments made from moisture-wicking material and ensuring they are cleaned with a mild detergent. This should help keep your skin irritation-free and dry. Another effective approach is following a consistent workout routine that gradually increases in intensity. You may find it beneficial to consult a running coach for creating a tailored plan that suits your fitness level. If your body is reacting adversely to your current workout intensity, it might be an indication that you're pushing yourself too hard. Try interspersing walks within your running sessions, reduce the duration or decrease the overall intensity of your workouts. This would enable your body to adapt better to the increased blood flow, preventing fatigue. Like all things, going from one extreme to another can be detrimental to your body. Hence, providing it with adequate stress and allowing sufficient recovery time is key to overcoming runner's itch.