Fatigue
By the AllHealth UK editorial teamLast reviewed Next review due Compiled from published NHS and NICE guidance. Not reviewed by a clinician.
Key facts
Fatigue is more than just feeling tired — it's a persistent feeling of exhaustion that doesn't improve with sleep. It can be physical, mental, or both, and affects your ability to function normally day to day.
Most often affects:New parentsShift workersPeople with chronic conditionsAdults 30–50
What commonly causes fatigue
- Poor sleep quality or insufficient sleep
- Stress, anxiety, and depression
- Iron deficiency anaemia — especially common in women
- An underactive or overactive thyroid
- Sedentary lifestyle — counterintuitively, less activity = more fatigue
- Dehydration and poor nutrition
- Chronic fatigue syndrome (ME/CFS)
- Undiagnosed diabetes — tiredness with extra thirst, peeing more often (especially at night) and weight loss
- Sleep apnoea — tiredness in the day because breathing stops and starts at night; you may snore loudly or make gasping noises
What helps at home
- Aim for 7–9 hours of quality sleep — consistency matters more than duration
- Exercise regularly — even a 20-minute daily walk boosts energy
- Eat a healthy balanced diet — but if you're tired all the time and don't know why, see a GP rather than assuming it's low iron; the NHS says not to self-diagnose.
- Stay hydrated — even mild dehydration causes fatigue
- Avoid caffeine and alcohol in the 6 hours before bed — NHS advice, and later than most people expect
- Practice stress management — meditation, journaling, or breathing exercises
- Do not smoke, and do not drink too much alcohol
When to get help
These three levels are different. Getting the level right is the single most useful thing this page can do for you.
Non-urgent advice: see a GP if
- Fatigue has lasted more than 4 weeks despite better sleep and routine
- You have lost or gained weight without trying
- You have heavy periods alongside the tiredness
- You feel low in mood as well as tired
- You snore heavily and wake unrefreshed
Urgent advice: ask for an urgent GP appointment or call 111 if
- You are very thirsty, passing urine far more than usual, and losing weight
- You are breathless or your heart races when you do very little
- You have become exhausted over just a few days and feel unwell with it
- You feel faint, or you have nearly passed out
Immediate action required: call 999 or go to A&E if
- Sudden extreme fatigue with chest pain or difficulty breathing
- Fatigue with confusion, slurred speech, or weakness on one side
What to do next
Not sure whether fatigue needs a doctor? These are your options, cheapest and fastest first.
Questions people ask about fatigue
Reducing the chance of it coming back
- Establish a consistent sleep schedule — same time every day, including weekends
- Get 150 minutes of moderate exercise per week
- Limit screen time before bed — blue light disrupts melatonin
Conditions this can be part of
Listed alphabetically, not by likelihood — this page does not tell you which one you have.
- Anaemia
- Chronic fatigue syndrome
- Depression
- Hypothyroidism
Sources and further reading
This page was written from the following published guidance. All links checked 26 August 2026.
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