Whether you're a running newbie or have logged hundreds of miles, no one is immune to the sudden, debilitating, painful cramp in your side. Sometimes referred to as a side stitch, we asked experts to tell us what causes them and, more importantly, what you can do during a run to stop a cramp fast.

What Causes a Side Stitch When Running?

A side stitch occurs when the diaphragm is in spasm, explained Kate Mihevc-Edwards, OCS, a doctor of physical therapy, with a focus on treating runners and triathletes. She said that the diaphragm is an important muscle for runners because it's integral in posture, core stability, and is responsible for breathing. It is a domed-shaped muscle located under your rib cage that expands as you inhale and contracts as you exhale. "Like any other muscle, the diaphragm fatigues. When the diaphragm is under stress or fatigued, it may go into spasm, causing a side stitch," Kate explained.

How Do You Stop a Side Stitch When Running?

There are several strategies you can try to relieve a side stomach cramp when running.

• Breathe slower: Slow your breathing down and focus on long exhalations, Kate advised. This will decrease the rate of contraction as well as tap into the parasympathetic nervous system, which helps regulate your breathing.
• Breathe in through your nose: "What I tell clients to do, and this strategy works for me as well, is to continue running but breathe in through your nose (as you should be doing during your run anyway), but then breathe out through your mouth," advised ACE-certified trainer Lyuda Bouzinova. She added to make sure you take deep breaths and on the exhale, breathe all the air out of your lungs. Continue to do this until the cramp goes away, which should take a few cycles of breath, in and out. With this technique, you can continue running and not have to stop.
• Connect your breath with your steps: "My favourite remedy is to breathe out hard when you step with the foot on the side of your cramp (e.g. if the cramp is on your right side, every time you put your right foot down, breathe out hard)," said Stephanie Blozy, MS, an exercise science expert and owner of Fleet Feet [1] in West Hartford, Connecticut in the US.
• Do belly breathing: "Starting to belly breath is a great way to get rid of a stomach cramp. Slow down your breathing, focus on relaxing your abs and letting your belly expand as you breath in instead of breathing through your chest," recommended Jesse Lewis, DPT, who's also a NSCA-certified personal trainer and a weightlifting coach through USAW.
• Stretch it out: "Reach both hands above your head as you slowly inhale to help stretch out the muscle," Kate said. If that doesn't help, after a few breaths, you can also take one hand above the head and bend to the opposite side to stretch, focusing your breathing into the area you're stretching. Then repeat on the other side.
• Slow down: Try decreasing the intensity of your run, Kate said. Breathing too fast or too hard can cause a stomach cramp, and slowing down can help you regulate your breathing and allow the diaphragm to relax.
• Walk it out: If these strategies don't help, stop running and walk for a couple of minutes, advised ISSA-certified personal trainer Jamie Hickey. "Concentrate on your breathing and making sure to take deep full breaths."

How Do I Prevent a Side Stitch When Running?

Aside from breathing too hard, cramps can also be caused by eating too much before a run, not being properly hydrated, or having an electrolyte imbalance, said Matt Kite, CSCS, with D1 Training [2]. Although you want to ensure you're properly hydrated before a run, "some people get a side stitch when they drink too much water before a run," warned ACSM-certified exercise physiologist Melissa Morris. So try to spread out water consumption all day and avoid drinking too much directly before a run.