There are just a few culprits, right here. First up: Whenever you train, your coronary heart pumps extra blood to your arduous working muscle tissues. This momentum then causes your capillaries to expand, and as they accomplish that, they stimulate the encompassing nerve cells in your physique—and your mind interprets that sign as an itch. “This can be a extra seemingly state of affairs for the physique versus the face,” says board-certified dermatologist Deanne Mraz Robinson, M.D., FAAD, co-founder of Modern Dermatology and assistant scientific professor of dermatology at Yale New Haven Hospital, (since your bigger muscle teams are powering the toughest, and thus require extra blood circulate), “However the identical science applies.” 

Or, if you happen to’re vulnerable to flushing while working out, itch can definitely observe. “Train results in dilation of your blood vessels to reinforce circulation to your pores and skin and muscle tissues,” says board-certified dermatologist Joshua Zeichner, M.D. That is typically a very good factor—in any case, it’s elevated circulation that delivers vitamins to the cells and lends the beloved “post-workout glow.” However for some folks (particularly these with honest to medium pores and skin tones, delicate pores and skin, or circumstances like rosacea), it could actually result in irritation, which can lead to flushing, bumps, and, sure, itching.

In some instances, that prickly sensation may also characterize a kind of warmth rash, referred to as miliaria rubra. “This can be a situation the place there are blockages inside the sweat glands, resulting in tiny, pink bumps and a prickly or itchy feeling,” says Zeichner. “This develops when sweat is trapped within the glands due to points like non-breathable, moist exercise clothes sticking to the pores and skin.” It’s additionally way more frequent in sizzling, humid climate—say, if you happen to’re jogging exterior noon within the throes of summer season. 

And, lastly, folks can simply react to their very own sweat. Whereas sweat can effectively clear pores, some people could also be hypersensitive to its contents. “Moisture, warmth, and sweat can all trigger irritation of the pores and skin,” says Mraz Robinson. Easy as that.