Most people have experienced a side ache at some point while exercising. That cramp, ache or pain in the abdomen is commonly referred to as a stitch and is technically called an exercise-related transient abdominal pain.

Side aches are most likely experienced during distance running, swimming, cycling, horseback riding and team sports, according to an article from UpToDate.com, a resource for clinicians. They’re more likely to occur on the lower right side, according to the article.

“You can get a side ache from any activity especially if you are newer to it and (are) a younger athlete,” said Julie Downing, a professor of health and human performance at Central Oregon Community College.

There are different theories about what causes side aches, and no single, absolute explanation of their origins.

Here, with information provided by Downing and Eric Dildine, a physician assistant in the pulmonary department at St. Charles Bend, we overview what’s known about side aches.

Causes

Studies have suggested that abdominal cramping could come from inadequate blood supply (ischemia) to the diaphragm. During exercise, blood is diverted away from the diaphragm to the working muscles, reducing blood- oxygen supply to the abdominal organs, potentially creating an ischemic pain.

The pain also could be from stress to the ligaments that support abdominal organs, according to research cited in UpToDate.com.

The diaphragm pushes abdominal organs down and forward while lifting the ribs up during exercise, Downing said.

Add the jarring motion of running while breathing in and out, and it might stretch ligaments that connect the diaphragm to the internal organs, particularly the liver, she said. It seems, Downing said, when runners exhale as their right foot hits the ground it puts greater force on the liver, which is on the right side just below the rib cage. As the liver is coming down, the diaphragm is rising on the exhale, and ligaments get stretched. “This repeated stretching (in running) may lead to spasms in the diaphragm which can cause pain,” she said.

Aches could also be related to eating before exercising. Or, Downing said, drinking highly concentrated sport drinks or juices that contain a lot of carbohydrates just before or during exercise can often trigger a side ache. “When a fluid-engorged stomach tugs on visceral ligaments attached to the diaphragm, the pulling causes pain,” she said.

Prevention

Several studies suggest the best way to prevent stitches is to gradually increase one’s level of fitness.

“The more your body gets used to exercising, the less likely you will get side stitches,” Downing said.

Try to keep your breath regular and foot strikes light, especially when running downhill, she added.

Experts also advise avoiding fatty or high-caloric meals for three hours before exercise, as well as reconstituted fruit juices and beverages that are extremely concentrated with carbohydrates.

“When drinking during exercise, take small amounts frequently rather than a single large drink at a rest stop or aid station,” she said.

Relieving

Exercise-related side aches usually resolve themselves if you simply stop what you’re doing or at least slow down.

There might be some things you can do to help relieve the pain.

Some small studies have demonstrated breathing through pursed lips after deep inhalation or bending forward while tightening abdominal muscles might work. Downing expanded on that: Press on the site of the pain with your hand, bend forward to stretch the diaphragm and tighten the abdominal muscles.

“Breathe deeper to move air into the lungs at the beginning of each breath but don’t force more air out at the end of each breath,” she said.

Stretching tall might help, too. Raise the right arm straight up and lean toward the left, hold for 30 seconds, and then stretch the other side.