Why You Get A Side Stitch While Running

modeled by Ann Christine Velaquez; photographed by Caroline Tompkins; produced by Julie Borowsky; produced by Lorenna Gomez-Sanchez; produced by Yuki Mizuma.
Getting a side stitch while you're running is kind of like when you're playing Mario Kart and someone hits you with the "lightning bolt" item: out of nowhere, you feel like you momentarily get zapped, and you have to slow down, but eventually it wears off and you can go back to your normal speed. If you've never played Mario Kart before, this analogy might not make a ton of sense, but chances are you've experienced the unique discomfort of "exercise-related transient abdominal pain," aka a side stitch, before.
Usually, these aching pains occur on one side of your torso (the right side is the most common location), and feel like a cramp, a pinch, or a jolt that goes away when you bend over or stop moving. It's really normal to experience a side stitch while running, and 70% of runners report getting them. But as common as they are, experts aren't entirely sure why they happen, although there are a few likely theories.
Basically, a side stitch is a cramp in the muscle that controls breathing, says Sabrina Strickland, MD, a sports medicine doctor at the Hospital for Special Surgery. Your diaphragm is the dome-shaped muscle beneath your lungs controls your breathing. During cardio exercise, or if you abruptly start an intense workout, the diaphragm can cramp up and cause a side stitch, she says.
Side stitches are a literal pain to deal, but they're not the end of the world, and there are actually a few ways you can prevent them. Ahead are some questions you may have about this mysterious, all too familiar running woe.
What typically brings on a side stitch?
While most people associate side stitches with running, they can happen during any activity that involves twisting motions of the torso, like swimming, cycling, basketball, and horseback riding. Additionally, lots of people find that they get side stitches when they eat before exercise, Dr. Strickland says. "Food in the stomach diverts blood flow to the GI tract, and away from other muscles, putting them at risk for cramping," she says. So, if you work out before letting your food digest, your diaphragm can cramp.
Does getting a side stitch mean you're out of shape?
Not necessarily — even elite athletes get side stitches sometimes. Studies have shown that people who exercise frequently tend to get fewer side stitches, but their side stitches are just as intense as the ones that less-conditioned people get. Other studies have looked at whether having a higher body mass index (BMI) can increase your likelihood of getting a side stitch, but it turns out there's no real link (not to mention, BMI doesn't give you any indication of a person's physical fitness). If you are new to exercise, your best bet is to progressively increase the intensity of your workouts rather than jump into something over your head, Dr. Strickland says.
How can you stop them from happening?
In the moment, most people feel better when they're able to bend over, or when they stop moving altogether — and that's pretty much all you can do. Dr. Strickland says she usually tells people to walk briskly and take some very deliberate, deep breaths when one strikes.
In terms of prevention, some studies have shown that strengthening your trunk and core (specifically your transverse abdominals, the deep layer of muscles that help control breathing) can lead to fewer side stitches. It's also wise to make sure you're hydrated and are getting enough electrolytes for the type of exercise you're doing, Dr. Strickland says. "I always tell patients who suffer from muscle cramps to eat bananas or drink orange juice," she says. Other than that, make sure you give yourself adequate time to warm up before jumping on the treadmill — and, you know, look out for any lightning zaps.

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