Running News Daily

Why Do My Legs Itch When I Run?-Consider it growing pains for pounding the pavement.

When I first started running, an unexpected question popped to mind at the end of my first few workouts: Why do my legs itch when I run?

I knew I’d feel breathless, sweat profusely, and check my watch every 30 seconds in the hopes that five minutes had gone by since I last checked. What I didn’t expect was that I’d end my runs with actual red scratch marks down my thighs, thanks to the harder-than-I-meant-to scratching to ease the itch that kicked in just as I began to wrap things up.

Within a couple of weeks, the annoying itching that accompanied my runs stopped, and I forgot all about it. Then recently, I heard others anecdotally mention it, which made me think maybe it was not just a weird quirk with my body—maybe there’s actually something about starting running that really makes your legs itch.

Turns out, there’s a pretty reasonable physiological adaptation that could easily explain the itching. And in most cases—like mine—it’ll stop soon after your body gets used to the new exercise. But in some cases, there might be something more going on.

With many people starting running (or getting back into running) as a way to get in some exercise—or simply get a change of scenery—with gyms still closed due to the coronavirus, it’s a problem that lots of people may begin to experience. And if you’re one of them, you don’t need to freak out. Here’s everything you need to know about why your legs itch while you run.

Why do my legs itch when I run?

First, it helps to understand what happens to your body when you start a new aerobic activity. When you exercise hard enough to increase your heart rate for a sustained period of time, your muscles require more oxygen to help you get the job done. And you need greater blood flow to help deliver it.

“One of your body’s initial responses to running if you’ve never done it before is called vasodilation, where your blood vessels open up or expand to let more [blood] come through,” Geoff Burns, Ph.D., a researcher at the Michigan Performance Research Laboratory at the University of Michigan and competitive ultrarunner, tells SELF.

When you first start running, though, your body isn’t used to the increased demand on your blood vessels.

“If you think of the blood vessels in your muscles like city roads, when you start to run, you’re going to have more traffic on the road—it’s going to get congested,” he says. “These vessels aren’t mechanically used to expanding like that, and that might put pressure on some of the nerve tissue in the muscles or other mechanoreceptors there. That can give you that itchy sensation.”

That itchy feeling tends to be centered primarily in your legs, since your lower-body muscles are doing the most work when you run—meaning they’re going to require the most oxygen and thus greatest blood flow, he says. And it’s possible that you feel it more when you end your workout, because when you stop running, your blood pools briefly.

Can itchy legs while running be something else?

If your legs itching while running is caused by that physiological adaptation, it should only last a few weeks, says Burns—which was pretty much the case for me. After that time, your body should get used to that increased pressure in your blood vessels. Plus, your body helps the process along with other adaptations, like with the remodeling of existing blood vessels and the formation of new capillaries, which helps relieve some of that congestion.