That sharp, cramping pain in your side during a walk is almost always a side stitch, formally called exercise-related transient abdominal pain, or ETAP. It strikes somewhere between your lower ribs and your hip, usually on the right, and it tends to ease up when you slow down or stop. Surveys of active people find that roughly six in ten have experienced a side stitch within the past year, and walking is vigorous enough to trigger one, especially if you are out of practice or moving at a brisk pace.1PubMed Central. Exercise-Related Transient Abdominal Pain (ETAP) While the stitch itself is harmless and temporary, side pain during walking can occasionally point to something else worth investigating.
How Common Side Stitches Really Are
If you have ever felt embarrassed by a side stitch on what seemed like a mild walk, you are in large company. A survey of nearly a thousand participants across six sports found that 61 percent had experienced ETAP in the previous year, and the rates varied by activity. Running provoked it in about 69 percent of respondents, horse riding in 62 percent, and cycling in only 32 percent. Running and horse riding were roughly ten times more likely to cause a stitch than cycling after researchers controlled for personal characteristics like age and fitness level.1PubMed Central. Exercise-Related Transient Abdominal Pain (ETAP) Walking was not broken out separately in that study, but the pattern tells you something useful: activities that involve more vertical bouncing of the torso are bigger stitch triggers than smooth, seated movement like cycling. A brisk walk sits somewhere in the middle of that spectrum, and a hilly route or uneven terrain bumps it closer to running’s territory.
Even within a single running event, anywhere from 17 to 27 percent of participants report a stitch. That means the pain is genuinely common during moderate exercise, not a sign that something is wrong with you in particular.
What Is Actually Happening Inside Your Body
Researchers have debated the mechanism behind side stitches for decades, and the honest answer is that no single explanation has been proven beyond doubt. Several plausible theories exist, and the pain probably has more than one trigger depending on the person and the circumstances.
The leading current theory involves the peritoneum, the thin two-layered membrane that lines the inside of your abdominal wall and wraps around your organs. Movement during exercise can cause friction or tugging between those layers, especially when the space between them is less well-lubricated. That irritation produces a localized, sharp or stabbing pain, often on one side. Research in the early 2000s shifted attention toward this peritoneal-irritation model after finding that older explanations did not hold up well under scrutiny.2Medicine & Science in Sports & Exercise. Characteristics and etiology of exercise-related transient abdominal pain
One of those older explanations blamed the diaphragm. The idea was that exercise diverted blood away from the diaphragm, causing it to cramp. It is a neat story, but it does not explain why side stitches happen during swimming, where the diaphragm works differently, or why the pain is usually felt well below the diaphragm. Another historical theory proposed that organs like the liver and spleen swell with blood during exercise and pull on ligaments that suspend them. That idea dates back to at least the 1920s and was for a long time the standard textbook explanation.3JAMA Network (Archives of Internal Medicine). CAUSE OF THE SO-CALLED SIDE ACHE THAT OCCURS IN NORMAL PERSONS: PERSONAL OBSERVATIONS The visceral-ligament hypothesis has not been definitively ruled out, but it struggles to explain many of the clinical features of stitches, including the fact that they happen in non-upright activities and can occur on either side.
Muscle cramping in the abdominal wall itself is yet another possibility. Your core muscles work harder than you might expect during walking, especially on uneven ground or at a fast pace, and a localized cramp could produce a sharp side pain that resolves with rest. This mechanism and the peritoneal-irritation theory are not mutually exclusive; both may contribute in different episodes.
Blood Flow Gets Rerouted When You Move
Your body has a limited supply of blood, and during exercise it makes tough choices about where to send it. Working muscles demand more, so flow to the gut and abdominal organs gets dialed back. During fasting cycling exercise, blood flow to the splanchnic region (the organs served by the major abdominal arteries) drops by roughly 43 percent, with the blood supply to the liver and spleen area falling by about half.4PubMed Central. Mesenteric, coeliac and splanchnic blood flow in humans during exercise That redistribution is a normal physiological response, not something dangerous, but it helps explain why your gut can feel uneasy during exercise and why eating shortly before activity tends to make stitches worse. A full stomach means more blood is needed for digestion at exactly the moment the body wants to send it elsewhere, creating a tug-of-war in your abdomen.
This blood-flow shift also contributes to the broader category of exercise-related gastrointestinal symptoms, things like nausea, cramping, and bloating during a walk or run. If you find that your side pain comes with an upset stomach or an urge to find a bathroom, reduced gut blood flow during movement is a likely contributor.
Who Gets Side Stitches More Often
Younger people are substantially more prone to side stitches than older adults. The reason is not entirely clear, but it may relate to differences in peritoneal sensitivity, core stability, or simply the intensity of exercise relative to fitness level. In the large surveys that tracked ETAP, the decline with age was consistent and significant.
Fitness level matters too, though not in the direction you might expect. While deconditioned people tend to get more stitches when they start a walking program, well-trained athletes are not immune. Runners who train regularly still report stitches at high rates. The differentiator seems to be less about aerobic fitness and more about how accustomed your trunk is to the specific pattern of movement. Someone who walks daily but takes up jogging may get a stitch on the first few jogs despite being plenty fit for walking.
Eating and drinking before exercise is one of the most reliable triggers. Large meals, sugary or high-osmolality drinks, and carbonated beverages within an hour or two of exercise all increase stitch risk. The mechanism ties back to that blood-flow competition described above: a full gut demands blood that the body wants to redirect to muscles, and a distended stomach may press against or pull on the surrounding peritoneum.
The Surprising Link Between Stress and Side Pain
There is an intriguing connection between psychological stress and the likelihood of getting a side stitch. A study of runners found that those who reported ETAP had meaningfully higher scores on validated measures of both perceived stress and anxiety compared with runners who did not get stitches. After adjusting for age and running experience, the stitch-prone group scored about 4 points higher on a standard perceived-stress scale and about 3.4 points higher on a combined cognitive and somatic anxiety inventory.5Clinical Journal of Sport Medicine. Thorn in Your Side or Thorn in Your Head? Anxiety and Stress as Correlates of Exercise-Related Transient Abdominal Pain
The stitch-prone runners also reported more gastrointestinal symptoms at rest, suggesting that the gut-brain axis plays a role. Anxiety increases muscle tension and alters gut motility, both of which could prime the abdominal area for pain during movement. The correlation between anxiety scores and stitch frequency was modest but statistically meaningful. This does not mean a side stitch is “all in your head,” but it does suggest that managing stress might reduce how often it happens, particularly if you notice stitches tend to flare up during anxious periods or high-pressure events.
How to Stop a Side Stitch Mid-Walk
When a stitch hits, most people instinctively slow down, and that is the right call. Reducing your pace or stopping briefly almost always helps, because it reduces the repetitive mechanical stress on your abdomen and lets blood flow normalize. Beyond slowing down, a few specific maneuvers tend to speed relief:
- Deep belly breathing: Take slow, deliberate breaths that expand your belly rather than your chest. This relaxes the diaphragm and the abdominal wall simultaneously.
- Press and lean: Push your fingers gently into the site of the pain while bending slightly toward the painful side, then slowly lean away from it. The pressure seems to reduce peritoneal irritation, and the stretch may relieve a localized cramp.
- Exhale on the opposite foot strike: If you are walking fast enough for a clear stride pattern, try breathing out as the foot opposite the painful side hits the ground. This shifts the timing of diaphragmatic and abdominal muscle contractions and can break the cycle.
- Tighten a belt or waistband: Some people find that firm compression around the lower ribs helps, likely for the same reason that pressing into the area works.
None of these techniques have been tested in large randomized trials, so the evidence is largely anecdotal and clinical experience. But they are low-risk and widely reported to help.
Preventing Stitches Before They Start
Prevention is more effective than mid-stitch remedies, and the strategies are straightforward. Avoid eating a large meal within two hours of your walk. If you need fuel beforehand, keep it small and low in fat and fiber. Sip water rather than gulping large amounts, and skip carbonated or heavily sweetened drinks before heading out.
Warming up matters more than many walkers realize. If you launch into a brisk walk from sitting at a desk, your body has to make abrupt cardiovascular adjustments, including that gut-blood-flow diversion. Starting at an easy pace for five to ten minutes gives your circulatory system time to redistribute blood gradually rather than all at once.
Core strengthening may help over the longer term. A stronger trunk is better equipped to absorb the repetitive impact of walking without the peritoneal tugging or muscle cramping that seems to cause stitches. Exercises that challenge rotational stability, like planks with arm reaches or Pallof presses, are more relevant than traditional crunches, because walking involves rotation more than forward flexion.
If you tend to walk hunched forward, that posture could be a contributing factor. People with a more flexed trunk posture during walking show different neuromuscular activation patterns in their abdominal and back muscles.6PLOS ONE. Effects of sudden walking perturbations on neuromuscular reflex activity and three-dimensional motion of the trunk in healthy controls and back pain symptomatic subjects While that study looked at back-pain populations rather than stitches specifically, the connection is plausible: altered trunk mechanics change how forces are distributed across your abdominal contents, and that redistribution could make peritoneal irritation more likely.
When the Pain Is Not a Stitch
A classic side stitch is predictable, brief, and tied clearly to activity. It comes on during exercise, stays in roughly the same spot, and fades within minutes of slowing down. If your side pain does not fit that description, it is worth considering other explanations.
Musculoskeletal causes are common and frequently overlooked. A strained oblique muscle, a rib stress reaction, or referred pain from the thoracic spine can all produce side pain that gets worse with walking. The giveaway is usually that the pain can be reproduced by pressing on a specific spot or by twisting your trunk in a particular direction, even when you are not exercising.
Gastrointestinal conditions can mimic a stitch. Trapped gas in the colon, particularly at the splenic flexure on the left side, produces a sharp localized pain that can feel identical to a stitch. Irritable bowel syndrome, constipation, and even mild food intolerances can all cause abdominal pain that worsens with movement because walking jostles the gut.
Kidney stones are another consideration, especially if the pain is in your flank or slightly toward your back, comes in waves, and does not respond to the usual stitch-relief techniques. Urinary tract infections can produce a similar location of pain, usually with additional symptoms like burning with urination or fever.
For women, reproductive-system conditions including ovarian cysts, endometriosis, and, rarely, ectopic pregnancy can cause one-sided abdominal or pelvic pain that becomes more noticeable during walking. A systematic review of abdominal pain presentations found that lateralized or flank pain has diagnostic relevance when evaluating for ectopic pregnancy, underscoring that the location of pain gives clinicians meaningful information.7PubMed Central. Signs and symptoms of serious illness in adults with acute abdominal pain presenting to ambulatory care: a systematic review
Red Flags That Warrant a Doctor Visit
Most side pain during walking is benign, but certain features should prompt you to see a healthcare provider rather than assuming you have a stitch:
- Pain that persists after rest: A true stitch resolves within minutes of stopping activity. Pain that lingers for hours or is still there the next day points to a different cause.
- Fever or chills: These suggest infection or inflammation, not a mechanical stitch.
- Blood in urine or stool: This needs investigation regardless of timing.
- Sudden severe pain: A stitch usually builds gradually. An abrupt, intense onset can indicate something like a kidney stone, an ovarian cyst rupture, or, in rare cases, a splenic or hepatic problem.
- Pain that worsens over days: A stitch does not get progressively worse over multiple walks. Escalating pain suggests an underlying condition.
- Unexplained weight loss or night sweats: These systemic symptoms combined with abdominal pain require medical evaluation.
If you are over 50 and experiencing new-onset side pain during walking that you have never had before, it is especially worth getting checked out. New gastrointestinal symptoms in that age range deserve at least a conversation with your doctor, even if the pain fits the pattern of a stitch.
Why the Right Side Gets Hit More Than the Left
People report side stitches on the right about twice as often as on the left. The liver sits on the right side of the abdomen, and it is the heaviest single organ in the torso. During walking and running, the liver bounces with each stride, and the connective tissue attaching it to the diaphragm and abdominal wall transmits that motion. The mechanical load on the right side is simply greater, which fits both the peritoneal-irritation and the visceral-ligament hypotheses for stitches.
Left-sided stitches do happen, though, and when they do, they are more often associated with eating before exercise. The stomach and splenic flexure of the colon sit on the left, and a full stomach adds weight and distension on that side specifically. If your stitches are consistently left-sided, pay extra attention to meal timing before your walks.
Side Pain on a Walk Versus a Run
You might assume that walking is gentle enough to avoid stitches entirely, but the threshold is lower than many people think. A brisk walk at 4 miles per hour generates meaningful vertical oscillation of the torso, especially on hard surfaces. Add an incline, a loaded backpack, or shoes with poor cushioning, and the forces on your abdominal contents increase further.
That said, stitches are genuinely less common during walking than running. The reduced impact and slower pace mean less peritoneal jostling and a smaller blood-flow redistribution. If you are getting stitches every time you walk at a moderate pace, that pattern is unusual enough to consider whether something other than a simple stitch might be going on, or whether a modifiable factor like pre-walk eating, shallow breathing, or a very hunched posture is the real culprit.
For people returning to exercise after a long break, the first few weeks often bring the most stitches. Your trunk muscles and peritoneal tissues adapt to the mechanical demands of walking over time, much like your cardiovascular system adapts to the aerobic demand. The stitches tend to become less frequent and less severe with consistent activity, which is both reassuring and a good reason not to let a few early stitches derail a new walking habit.