Tired all the time despite sleeping: causes, red flags and when to get it checked

Fatigue is a nonspecific symptom with physical, psychological and lifestyle contributors. Being tired despite sleeping suggests that sleep is not restorative, that the body is short of something it needs, or that mood or illness is draining energy. Rarely it signals a serious condition, so assessment focuses on common treatable causes while watching for red flags.

• Lifestyle: irregular sleep, shift work, excess screens, caffeine, alcohol, poor diet and overwork.

• Depression, anxiety and stress, often with low motivation and early waking.

• Obstructive sleep apnoea: snoring, gasping, morning headache and daytime sleepiness.

• Iron deficiency and anaemia, vitamin B12 or folate deficiency, and low vitamin D.

• Underactive thyroid, diabetes and menopause or perimenopause.

• Medicines: antihistamines, beta blockers, sedatives, opioids and some antidepressants.

• Post-viral fatigue, long COVID and chronic fatigue syndrome (ME/CFS).

• Coeliac disease, kidney, liver or heart disease, infections such as glandular fever or HIV, and cancers including lymphoma.

Unexplained weight loss, fevers, drenching night sweats, breathlessness, chest pain, persistent cough, blood in stool or urine, swollen glands, yellowing of skin, severe headaches, symptoms lasting over months with rapid worsening, and thoughts of self-harm warrant prompt attention.

• Call 999 or Samaritans on 116 123 (free, 24 hours) or go to A&E: thoughts of ending your life, or fatigue with chest pain, severe breathlessness or collapse.

• GP within days: tiredness with weight loss, fevers, night sweats, lumps or bleeding.

• GP within weeks: unexplained tiredness lasting more than two to four weeks.

• Routine: tiredness after a busy period that improves with rest.

The doctor asks about onset, sleep pattern, snoring, mood, stress, diet, alcohol, caffeine, drugs, periods, menopause, weight change, bowel symptoms, medicines, recent illness and workload. They examine for anaemia, thyroid enlargement, lymph nodes, heart, lungs and abdomen, and screen for depression and sleep apnoea.

• Blood tests: full blood count, ferritin, B12, folate, vitamin D, thyroid function, HbA1c, kidney, liver and calcium, with CRP and coeliac screen where indicated.

• Sleep study: if sleep apnoea is suspected.

• Depression and anxiety questionnaires.

• Further tests (HIV, glandular fever, cortisol, imaging) guided by findings.

• Many people have normal tests, which can be reassuring and shifts focus to sleep, mood and lifestyle.

Keep regular sleep and wake times, get daylight and moderate exercise, limit caffeine after midday and alcohol, eat regularly and pace activities. Talk to someone if mood is low. Avoid unproven "adrenal fatigue" tests and expensive supplement regimes. Treat any cause that is found.

The NHS route is a GP and blood tests, with sleep, endocrinology or fatigue services as needed. Private GP and screening services can arrange broad blood panels, but interpretation matters more than the number of tests.