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Ask Us Anything: What causes side stitches when you exercise?

Is your head constantly spinning with outlandish, mind-burning questions? If you’ve ever wondered what the universe is made of, what would happen if you fell into a black hole, or even why not everyone can touch their toes, then you should be sure to listen and subscribe to Ask Us Anything, a brand new podcast from the editors of Popular Science. Ask Us Anything hits Apple, Anchor, Spotify, and everywhere else you listen to podcasts every Tuesday and Thursday. Each episode takes a deep dive into a single query we know you’ll want to stick around for.


The sharp pain while exercising is dreaded and all too common. Despite our best efforts to stay well-hydrated, warm-up, and take it easy when needed, side-stitches still plague as many as two in three runners each year. And the stabbing ache doesn’t just plague joggers, but nearly every exerciser from swimmers to horseback riders. And though many may experience it, the science behind it isn’t well understood. 

Researchers have a handful of theories they’ve been bouncing around for the past few decades, at least, to attempt to explain the physiological underpinnings of the humble side stitch. Still the stitch endures, and remains somewhat of a mystery. Listen to this week’s episode to hear how close scientists are to solving the mystery of the side stitch and what you might be able to do to prevent yourself from getting one.

Claire Maldarelli

Claire Maldarelliis the Science Editor at Popular Science. She has a particular interest in brain science, the microbiome, and human physiology. In addition to Popular Science, her work has appeared in The New York Times, Scientific American, and Scholastic’s Science World and Super Science magazines, among others. She has a bachelor’s degree in neurobiology from the University of California, Davis and a master’s in science journalism from New York University’s Science, Health, and Environmental Reporting Program. Contact the author here.