Lateral abdominal pain, often described as a pain in your side or flank, is a common experience ranging from fleeting irritation during physical activity to a sign of a more significant underlying issue. This discomfort occurs specifically in the area between the ribs and the hip bone and is either caused by or noticeably worsened by the motion of walking. Pinpointing the origin requires distinguishing between sources that are muscular, digestive, or related to internal organs. While many instances are benign and linked to movement, understanding the specific characteristics of the pain helps determine its true cause and the appropriate course of action.
Understanding the Common Exercise-Related Pain
The most frequent cause of temporary side discomfort during movement, particularly walking or running, is Exercise-related Transient Abdominal Pain (ETAP), commonly known as a side stitch. This pain is typically localized in the lateral mid-abdomen, often along the lower edge of the rib cage. It is usually described as a sharp, stabbing sensation when severe, or a cramping, aching feeling when less intense.
The precise mechanism for ETAP remains under investigation, but the leading hypothesis involves the irritation of the parietal peritoneum, a membrane lining the abdominal cavity. Repetitive jarring movements may cause strain on the ligaments connecting the diaphragm to internal abdominal organs, such as the stomach and spleen. Another theory suggests the diaphragm muscle experiences a temporary reduction in blood flow as blood is redirected to the working leg muscles during exercise.
Consuming large volumes of food or beverages, especially those high in sugar, within one to two hours before exercise increases the likelihood of ETAP. To manage a stitch immediately, slow down the activity and focus on deep, diaphragmatic breathing. Applying gentle pressure to the painful area while bending forward slightly may also offer rapid relief, often allowing the pain to subside within minutes.
Musculoskeletal and Postural Contributors
Pain in the side that is structural rather than visceral often originates from the muscles, bones, or nerves of the torso and is directly aggravated by the mechanical stresses of walking.
Muscle Strain and Posture
The oblique abdominal muscles are frequently involved because they are responsible for the twisting and stabilizing motions required with every step. An oblique muscle strain, or “side strain,” presents as sharp pain on the side of the abdomen that worsens with twisting, coughing, or moving from seated to standing. Poor posture during walking can also lead to chronic muscular pain by placing uneven stress on the trunk.
A slumped upper back restricts the mobility of the rib cage and thoracic spine, forcing core muscles to compensate. This imbalance can contribute to costochondritis, an inflammation of the cartilage connecting the ribs to the breastbone, causing sharp pain that radiates to the side and is exacerbated by deep breaths.
Nerve and Spinal Issues
Another mechanical cause is intercostal neuralgia, which is pain arising from the nerves running between the ribs. Movement can compress or irritate these nerves, resulting in a sharp, burning, or shooting pain that wraps around the side of the body. Pain from spinal issues, such as a herniated disc or spinal arthritis, can also radiate outward to the flank area. The jarring motion of a normal gait often intensifies this nerve impingement.
Internal Organ and Digestive System Causes
When side pain persists beyond exercise or is accompanied by other symptoms, it may indicate an issue with an internal organ, where the pain is aggravated by the motion of walking.
Digestive System
Digestive issues are a common culprit, as body movement can jostle the intestines and move trapped gas. Gas accumulation, particularly in the bends of the colon (splenic flexure on the left or hepatic flexure on the right), can cause intense, cramping pain.
Right Side Organs
Pain localized to the right side may be linked to the gallbladder, which sits beneath the liver. Gallstones or inflammation (cholecystitis) cause sudden, severe pain in the upper right abdomen that sometimes radiates to the back or flank. Liver conditions, such as inflammation or enlargement, can also produce a dull, aching discomfort in the upper right quadrant.
Left Side and Flank Organs
For pain felt high up under the left ribs, concerns related to the spleen may be considered. An enlarged spleen, often due to infection, causes discomfort and tenderness intensified by the jarring motion of walking. Pain in the flank area, on either side, is often a sign of a kidney issue, as the kidneys sit in the mid-back area just under the ribs. Kidney stones or a kidney infection (pyelonephritis) produce severe, radiating pain aggravated by movement, sometimes accompanied by changes in urination.
Identifying Warning Signs and When to Seek Medical Help
While most side pain during walking is temporary and harmless, certain accompanying symptoms signal that the issue is not a simple stitch or muscle strain and requires immediate medical evaluation.
Seek immediate medical attention if you experience:
- Sudden and severe pain, difficulty breathing, or chest tightness.
- A high fever or chills alongside the side pain, suggesting an infection like pyelonephritis or diverticulitis.
You should consult a doctor if the pain is accompanied by other concerning signs:
- Blood in the urine or stool, persistent vomiting, or jaundice (yellowing of the skin or eyes).
- Pain severe enough to wake you from sleep or that persists for several days without improvement.
- An acute, new bulge in the abdomen or groin area, which may suggest a hernia.
- Pain that radiates to the shoulder or groin.