Side stitches are not a running problem. They happen during swimming, cycling, horseback riding, aerobics, and even activities as simple as brisk walking or bending at the waist. Researchers call them exercise-related transient abdominal pain, or ETAP, and surveys of athletes find they occur across virtually every sport that involves torso movement. The sharp, stabbing sensation under your ribs can also show up in situations that have nothing to do with exercise, which makes the experience confusing and sometimes alarming.
What a Side Stitch Actually Is
Despite decades of study, scientists still debate the exact mechanism behind side stitches. Several theories have been proposed, including reduced blood flow to the diaphragm, stress on the ligaments that suspend abdominal organs, cramping of the abdominal wall muscles, and compression of the celiac artery. The explanation that currently fits the evidence best is irritation of the parietal peritoneum, the thin membrane lining the inside of your abdominal cavity.1PubMed Central. Exercise-related transient abdominal pain (ETAP) When this membrane gets rubbed, stretched, or compressed during movement, the friction generates that familiar localized pain, usually on the right side just below the ribcage.
The peritoneal theory explains why running is not uniquely guilty. Any activity that jostles, rotates, or compresses the torso can create the same friction on the abdominal lining. It also explains why eating or drinking before activity makes the pain worse: a fuller stomach presses more firmly against surrounding tissues and increases the mechanical irritation.
Activities That Trigger Side Stitches Besides Running
A survey of nearly a thousand regular sporting participants found striking numbers. About 75% of swimmers reported a side stitch within the past year, compared to 69% of runners. Horseback riders came in at 62%, aerobics participants at 52%, basketball players at 47%, and cyclists at 32%.2PubMed. Characteristics and etiology of exercise-related transient abdominal pain The pattern that emerged was clear: ETAP is most common in activities that involve repetitive up-and-down movement of the torso or rotation through the trunk.
When researchers controlled for other variables, running and horseback riding were each roughly ten times more likely to produce a stitch than cycling.3PubMed. Factors influencing exercise-related transient abdominal pain Cycling keeps your torso relatively stable, which seems to spare the peritoneum. Swimming, despite not having much vertical bouncing, involves constant trunk rotation and changes in breathing pressure, which may explain its surprisingly high stitch rate.
This also explains why you might get a stitch doing something that doesn’t feel like “real exercise.” Vigorous housework, playing with children, even laughing hard or coughing repeatedly involves enough torso movement to irritate the abdominal lining in susceptible people. If you have ever felt that familiar twinge while doing yard work or hauling groceries, the mechanism is the same one that hits runners mid-stride.
Why Eating and Drinking Make It Worse
One of the most reliable triggers for a side stitch, with or without running, is eating or drinking too close to physical activity. Research investigating fluid intake before exercise found that all tested beverages provoked stitches during the initial bouts of running. The type of fluid mattered less than the simple fact that there was something in the stomach.4PubMed Central. Investigation of the side pain “stitch” induced by running after fluid ingestion A full stomach is heavier, pushes against surrounding tissues more aggressively, and amplifies the mechanical irritation of the peritoneum with each movement.
This is why side stitches sometimes catch people off guard during non-running activities. You might never get one while jogging on an empty stomach, then feel a sharp stab while walking the dog after dinner. The combination of a recent meal and even moderate torso movement can be enough. High-sugar or high-fat drinks and foods seem to empty from the stomach more slowly, prolonging the window of vulnerability. If you keep getting stitches during mild activity, timing your meals to leave a gap of at least an hour or two before movement is the simplest fix.
Quick Relief Techniques
When a stitch hits, you do not need to stop everything and lie down. Research on relief maneuvers found that bending forward while tightening the abdominal muscles, tightening a belt around the waist, or breathing through pursed lips with increased lung volume all alleviated stitch pain within seconds.4PubMed Central. Investigation of the side pain “stitch” induced by running after fluid ingestion Interestingly, trying to relax the abdominal muscles or increasing the impact of foot strikes did not help.
The fact that tightening the core works but relaxing it does not is consistent with the peritoneal irritation theory. When you brace your abdominal muscles, you stabilize the contents of the abdomen and reduce the sloshing and friction against the peritoneal lining. Pursed-lip breathing with expanded lungs likely pushes the diaphragm down in a more controlled way, reducing the tugging and shifting that provokes pain. These are worth trying whether you are mid-jog, mid-swim, or just walking briskly after lunch.
Core Strength and Long-Term Prevention
People who experience side stitches frequently sometimes assume they are just unlucky or doing something wrong in the moment. But there is a structural component. A study examining the relationship between trunk muscles and stitch frequency found that participants with stronger trunk muscles and a larger resting transversus abdominis experienced ETAP less often.5PubMed. The effect of transversus abdominis activation on exercise-related transient abdominal pain
The transversus abdominis is the deepest layer of abdominal muscle, wrapping around the torso like a corset. When it is well-developed, it provides a natural brace for the abdominal contents, reducing the kind of internal movement that irritates the peritoneum. This may be one reason why elite athletes tend to report fewer stitches than recreational exercisers, and why stitches are more common in younger people (who often have less-developed core musculature relative to their activity level). If you get stitches regularly during everyday activities, targeted core strengthening over weeks and months can reduce their frequency. Exercises that engage the deep stabilizers, like planks, dead bugs, and Pallof presses, are more relevant here than sit-ups or crunches, which primarily work the superficial abdominal layers.
Age and Fitness Level
Side stitches become less common as you get older, which sounds like a silver lining but is actually a bit of a puzzle. Survey data consistently shows that younger athletes report ETAP at higher rates than older ones.2PubMed. Characteristics and etiology of exercise-related transient abdominal pain One possibility is that the peritoneum becomes less sensitive with age. Another is that older adults have generally developed stronger core musculature from years of activity, or have learned to avoid the food-timing triggers without thinking about it. Fitness level itself plays a role too: deconditioned individuals tend to report more stitches when they start a new exercise program, which partly explains why people who are “getting back into shape” find them frustratingly common.
The pattern is worth knowing because it reassures people who suddenly start getting stitches after a period of inactivity. If you took a few months off and are now getting them during relatively easy walks or light gym work, the stitches are likely to decrease as your conditioning improves, especially your deep core strength.
When It Might Not Be a Stitch
The casual label “side stitch” gets applied to any sharp, transient pain in the torso, but several other conditions can mimic the sensation and are worth knowing about, especially if your pain keeps coming back when you are not exercising at all.
Precordial Catch Syndrome
This is an extremely common and completely benign cause of sudden, sharp chest or side pain, especially in adolescents and young adults. The pain typically appears at rest, often when slouching or taking a deep breath, and lasts from a few seconds to a couple of minutes before vanishing entirely. Pediatricians report that precordial catch syndrome accounts for the vast majority of non-traumatic chest discomfort in young people.6Cardiovascular and Cardiometabolic Journal (CCJ). Precordial Catch Syndrome: Unveiling a Benign Yet Noteworthy Cause of Chest Pain in the Young It requires no treatment and is not dangerous, though the intensity of the pain understandably causes alarm. If your “side stitch” happens while sitting still, is very brief, and goes away on its own without any residual discomfort, this is a likely explanation.
Slipping Rib Syndrome
A much less well-known condition, slipping rib syndrome involves hypermobility of the lower ribs, which are not directly attached to the breastbone. When the cartilage connecting these ribs shifts out of place, it can trap the intercostal nerve, producing burning or sharp pain in the lower chest and upper abdomen.7PubMed Central. A new sign of the slipping rib syndrome? The pain can be intermittent, flaring with certain movements, and it is often mistaken for a chronic side stitch, a muscle strain, or even a gallbladder problem.8PubMed Central. Treatment of Chronic Pain Due to Slipping Rib Syndrome Using Ultrasound-Guided Intercostal Cryoneurolysis: A Case Report
Slipping rib syndrome primarily affects the 8th, 9th, and 10th ribs, and it is significantly underdiagnosed because many clinicians do not think to check for it.9Journal of Pulmonology and Intensive Care. Awareness and management of slipping rib syndrome If you have recurring pain in the lower rib or upper abdominal area that worsens with twisting, bending, or reaching, and it does not follow the typical stitch pattern of appearing only during exertion, this is worth mentioning to your doctor. A simple physical exam called the “hooking maneuver,” where the clinician curls their fingers under the lower rib margin and gently pulls outward, can reproduce the pain and help confirm the diagnosis.
Gallbladder Pain
Pain from the gallbladder, particularly biliary colic from gallstones, is classically felt in the right upper abdomen, exactly where most side stitches land. The key differences are timing and duration. Biliary colic typically comes on after fatty meals, builds to a steady ache or cramp (rather than a sharp stab), and lasts anywhere from 30 minutes to several hours. It can radiate to the back or the right shoulder blade.10PubMed Central. ABC of the upper gastrointestinal tract. Upper abdominal pain: Gall bladder If your “stitches” keep appearing after meals but not during exercise, persist for longer than a few minutes, and are accompanied by nausea, gallbladder disease is a more likely culprit than ETAP.
Celiac Artery Compression
In rare cases, the median arcuate ligament of the diaphragm compresses the celiac artery, restricting blood flow to the upper abdominal organs. This can cause recurring postprandial abdominal pain that some people describe as stitch-like.11PubMed Central. Celiac Artery Compression Syndrome as an Uncommon Cause of Intractable Postprandial Abdominal Pain: A Case Report The pain tends to be more severe and persistent than a normal stitch, and it may be accompanied by weight loss, nausea, or vomiting.12Pain Medicine Case Reports. Resolution of Celiac Artery Compression Syndrome Following Spinal Cord Stimulation: A Case Report This condition is uncommon, but it is relevant because compression of the celiac artery is actually one of the proposed mechanisms for ordinary exercise stitches. In most people, the compression is mild and transient during exertion. In a small number of people, the anatomy creates a more persistent problem.
Stress, Gut Sensitivity, and Stitches at Rest
Some people experience stitch-like sensations without any physical activity at all, sometimes while sitting at a desk or lying in bed. If structural causes like slipping rib syndrome and gallbladder issues have been ruled out, visceral hypersensitivity may play a role. Chronic stress is known to facilitate pain perception in the gut and abdominal organs, sensitizing the neural pathways that process visceral signals.13PubMed Central. Stress-Induced Chronic Visceral Pain of Gastrointestinal Origin People with conditions like irritable bowel syndrome often report heightened sensitivity to abdominal sensations that most people would not notice.
This does not mean the pain is imaginary. The peritoneal lining and surrounding structures are genuinely producing signals; the nervous system is just amplifying them beyond what the stimulus would normally warrant. If you are going through a high-stress period and notice more frequent unexplained abdominal twinges, the connection may be real. Addressing the stress itself, through sleep, exercise, or whatever works for you, can gradually dial down the sensitivity.
The Breathing Connection
Shallow, rapid breathing is often blamed for side stitches, and while it is not the root cause, breathing mechanics do matter. The diaphragm sits directly above the abdominal organs and below the lungs. When you breathe shallowly during exertion, the diaphragm stays in a relatively high, tensed position, which limits its ability to act as a buffer between the lungs and the abdominal contents. Researchers have noted that diaphragmatic ischemia (reduced blood flow to the diaphragm muscle) remains one of the competing explanations for ETAP, even though the peritoneal theory has more overall support.14PubMed. Stitch in the side: causes, workup, and solutions
The practical takeaway is that conscious diaphragmatic breathing during activity, inhaling deeply enough that your belly expands rather than just your chest, can reduce stitch frequency. This is not about following a rigid breathing pattern timed to your footfalls (a common but largely unsupported piece of advice). It is about making sure the diaphragm moves through its full range rather than staying locked high. The pursed-lip breathing technique that researchers found effective for acute relief works on a similar principle: it forces a slower, deeper exhalation that resets diaphragm position.
Why Side Stitches Almost Always Favor the Right Side
Most people report side stitches on the right, and the anatomy offers a straightforward explanation. The liver, the heaviest abdominal organ, sits on the right side just below the diaphragm. During vertical bouncing (running, horseback riding, jumping), the liver’s weight tugs on the ligaments and peritoneal attachments that hold it in place, creating more mechanical stress on the right than the left. Left-sided stitches do happen, and they are more commonly associated with the stomach and spleen, but they are reported less frequently in surveys.
People who consistently get left-sided pain, especially after eating, may be experiencing gastric distension rather than classic ETAP. A full stomach on the left side can produce very similar symptoms, which is part of why the pre-exercise meal timing advice is so effective: it addresses both the right-sided liver-tugging mechanism and the left-sided stomach-distension mechanism at once.
When to Talk to a Doctor
A standard side stitch resolves within minutes, does not leave lingering soreness, and can be clearly linked to some kind of physical activity or recent eating. Situations that warrant medical attention look different:
- Pain lasting hours: True ETAP is transient. Pain that persists beyond 10 to 15 minutes after you stop moving, or that comes on at rest and lasts for an extended time, suggests something else is going on.
- Associated symptoms: Nausea, vomiting, fever, changes in bowel habits, or unexplained weight loss alongside recurring abdominal pain point toward gastrointestinal or vascular conditions rather than a stitch.
- Reproducible with a specific maneuver: If you can trigger the pain by pressing on a rib or twisting in a particular direction even when resting, slipping rib syndrome or a musculoskeletal issue is more likely.
- Progressive worsening: Side stitches from exercise tend to improve with conditioning over time. Pain that gets worse over weeks or months, or that starts requiring less and less activity to trigger, deserves investigation.
Most people who search “why do I have a side stitch without running” are experiencing one of two things: ordinary ETAP triggered by non-running activity they did not realize counts, or a mimic condition that feels similar but has a different origin. The first group benefits from meal timing and core work. The second group benefits from getting the right diagnosis, which often requires specifically asking a clinician to check for conditions like slipping rib syndrome that tend to fly under the radar.