Diarrhoea after exercise

Running and other vigorous activity can jostle the bowel and speed contractions. Blood is also directed toward working muscles, which may make digestion feel unsettled. A large meal close to training, very sweet drinks, caffeine, heat, or dehydration can worsen urgency. Symptoms that happen only during demanding sessions may differ from diarrhoea that continues at rest. Recurrent symptoms can also overlap with Food Intolerance or Irritable Bowel Syndrome; persistent diarrhoea needs assessment for conditions such as Coeliac Disease, Crohn's Disease, or Hyperthyroidism. An infection such as Gastroenteritis or Food Poisoning can occur independently of exercise.

Stop or reduce the session if you feel weak, dizzy, overheated, or unable to replace fluids. Sip water regularly and consider oral rehydration solution after substantial fluid loss. Allow time for digestion before intense exercise, and test changes to meal size, fibre, caffeine, and sports drinks one at a time. Avoid training while feverish or vomiting. Clean hands and shared equipment if an infection is possible. Write down the activity, heat, food, drinks, symptoms, and recovery time so patterns are clear.

Seek urgent care for collapse, confusion, severe weakness, severe abdominal pain, blood or black stool, repeated vomiting, or signs of serious dehydration. Book medical advice if episodes recur, occur with gentle activity, persist after exercise stops, or come with fever, weight loss, night-time symptoms, or reduced urine. A clinician can review training, medicines, and bowel symptoms together.

Could my hydration plan, sports drink, or medicine be contributing? Should I alter training while this is investigated? What symptoms would make exercise unsafe for me?