Heart palpitations with diarrhoea and fatigue

Diarrhoea removes fluid and salts, which can make the pulse faster and cause tiredness, dizziness, or a dry mouth. An infection may produce a similar combination, especially with fever. Other possibilities include low blood sugar, anaemia, an overactive thyroid, anxiety, or an irregular rhythm such as atrial fibrillation. The symptoms do not identify one cause on their own, so their timing and severity are useful.

Rest and take frequent small sips of water or oral rehydration fluid. Eat simple foods when able, and avoid alcohol, caffeine, and heavy exercise until the diarrhoea and palpitations settle. Keep track of stool frequency, urine output, fever, pulse sensations, and medicines. Contact a clinician if symptoms continue, return, or make it difficult to drink or carry out normal activities.

Seek emergency help for fainting, chest pain, severe breathlessness, confusion, collapse, or a heartbeat that stays very fast or irregular. Get prompt medical advice for blood in the stool, severe abdominal pain, signs of significant dehydration, or inability to keep fluids down. Older adults and people with heart or kidney conditions may need earlier advice.

Ask whether you need an ECG, blood count, thyroid testing, or checks of salts and kidney function. Mention recent travel, sick contacts, new medicines, and whether the palpitations began before or after the diarrhoea.