Diarrhea and fatigue: what should you know?

Loose stools can remove water and salts, while nausea or cramping may make eating and drinking difficult. The resulting dehydration can cause thirst, headache, dizziness, dark urine, and low energy. An infection may make you feel washed out even after bowel symptoms begin improving. If diarrhea lasts or keeps returning, other conditions may need consideration, including coeliac disease, anaemia, chronic kidney disease, or COVID-19. Fatigue can also reflect burnout, alcohol-related health problems, or chronic fatigue syndrome; the combination does not prove any one diagnosis.

Sip fluids regularly, using an oral rehydration solution when stools are frequent or you are losing more fluid than usual. Eat small, simple meals as tolerated and rest. Avoid alcohol and strenuous exercise until your energy and urine output are returning to normal. Keep a brief record of stool frequency, fever, pain, weight change, urine, recent travel, new medicines, and foods that seem to trigger symptoms.

Arrange urgent assessment for fainting, confusion, severe weakness, inability to keep fluids down, very little urine, blood or black stool, severe pain, or breathing difficulty. Contact a clinician promptly if fatigue is worsening, diarrhea continues beyond a short illness, symptoms repeatedly return, or you have kidney disease, diabetes, pregnancy, or a weakened immune system. Children and older adults may dehydrate quickly.

Ask whether you need an examination, stool testing, or blood tests for anaemia, kidney function, or inflammation. Ask how much fluid to take, whether any medicine could be causing diarrhea, and when ongoing fatigue should be reassessed.