What should you know about very low energy?

Fatigue is more than feeling sleepy after a late night. It may feel like having too little physical or mental energy for everyday tasks, even after resting. The pattern matters: note when it began, whether it comes and goes, and how it affects work, driving, exercise or caring for yourself.

Short-lived fatigue can occur during recovery from an infection, after poor sleep, with inadequate fluids or during a demanding period. Low energy can also accompany conditions such as anaemia, coeliac disease, chronic kidney disease or COVID-19. Long-lasting exhaustion with symptoms that worsen after activity may need assessment for chronic fatigue syndrome. Mood, stress, alcohol use and some medicines can also affect energy and sleep.

The aim of an appointment is not to assume one cause. A clinician can consider your symptoms, daily routine, medicines and relevant examination or tests together.

For a few days, keep a simple record of sleep, meals, fluids, activity, stress and symptoms such as fever, pain, breathlessness, dizziness, weight change or bowel changes. This can make a consultation more useful. Keep regular meals and fluids where possible, and choose gentle activity only if it does not leave you feeling markedly worse afterward.

Avoid using alcohol as a sleep aid or energy reset, as it can disturb sleep and worsen tiredness. Do not stop prescribed medicine without advice; bring a full list of medicines, supplements and herbal products to your appointment.

Arrange a medical appointment if low energy persists, keeps returning, interferes with usual life, or comes with new symptoms you cannot explain. Seek urgent care for chest pain, severe trouble breathing, fainting, confusion, sudden weakness, coughing blood, black stools, or thoughts of harming yourself. These symptoms need prompt assessment regardless of the possible cause of fatigue.

Ask what features of your history point toward sleep, infection, nutrition, stress, medicine effects or another health condition. You can also ask whether examination or blood and urine tests are appropriate, what changes should prompt earlier review, and how to pace daily activities while the cause is being investigated.