Why am I always tired?
Last reviewed: 14 September 2026
There is a useful distinction hiding in this question. Feeling sleepy and feeling tired are not the same thing, and they point at different causes — one of which is not about sleep at all.
Tired and sleepy are different problems
If you sleep seven to nine hours and still feel exhausted, the cause is usually not sleep quantity. It is either the quality of that sleep, or something medical that has nothing to do with sleep at all.
That distinction is the useful first step. Sleepy means you would fall asleep given the chance. Tired means you lack energy but could not necessarily sleep. They point in different directions.
Start with the obvious three
- Are you actually sleeping enough? Not time in bed — time asleep. Adults need 7 to 9 hours. Many people who describe themselves as mysteriously tired are sleeping six and a quarter and counting it as seven.
- Is your sleep broken? Eight fragmented hours is not eight consolidated hours, and you will not remember the brief awakenings that caused it.
- Is your timing all over the place? Sleeping 11:00 PM–7:00 AM on weekdays and 2:00 AM–10:00 AM at weekends is a permanent mild jet lag even though both are eight hours.
If all three are fine, move on to the list below.
What the NHS lists as causes of persistent tiredness
Lifestyle
- Not enough sleep, or insomnia
- An unhealthy diet and not much exercise — being inactive is genuinely tiring, which is counter-intuitive but well established
- Alcohol, which degrades sleep quality even when it does not shorten it
Psychological
- Stress, and dealing with difficult life events including bereavement
- Depression — fatigue is one of its most common physical symptoms, and sometimes the first one people notice
- Caring for a baby or young children
Medical
These are the conditions the NHS specifically names in connection with persistent tiredness:
| Cause | What else you might notice |
|---|---|
| Sleep apnoea | Loud snoring, gasping or choking in your sleep, waking with a dry mouth or headache, sleepiness despite adequate hours. Commonly missed. |
| Iron deficiency anaemia | Breathlessness, pale skin, palpitations. One of the commonest causes, and very treatable. |
| Underactive or overactive thyroid | Weight change, feeling cold or hot, changes in mood or heart rate. |
| Diabetes | Excessive thirst, passing urine more often, unexplained weight loss. |
| ME / chronic fatigue syndrome | Exhaustion that is markedly worse after exertion and not relieved by rest. |
| Hormonal changes | Puberty, pregnancy and the menopause all commonly cause fatigue. |
| Infections and their aftermath | Glandular fever and COVID-19 both cause fatigue that can persist well after the illness. |
| Medication | Many medicines list fatigue as a side effect. Worth reviewing with a doctor or pharmacist rather than stopping anything. |
This list is here so you know what a GP will be thinking about, not so you can diagnose yourself. Several of these are identified with a simple blood test.
"Why am I always tired and have no energy?"
This is one of the most-searched versions of the question, often asked specifically by women, and there are reasons it comes up more often. Iron deficiency anaemia is considerably more common in women, particularly with heavy periods, in pregnancy, and in the years around the menopause. Thyroid disorders are also more common in women. Perimenopause causes fatigue both directly and through disrupted sleep.
All of which is to say: persistent unexplained tiredness in a woman of any age is worth a GP appointment and a blood test, not a resolution to try harder.
When to see a GP or doctor
The NHS says to see a GP or doctor if:
- you have been tired for a few weeks and are not sure why;
- the tiredness is affecting your daily life;
- it comes with other symptoms such as weight loss or changes in mood; or
- someone has noticed you gasping, snorting or choking in your sleep.
Fatigue is a symptom, not a personal failing, and "I'm just tired all the time" is a perfectly good reason to book an appointment.
What to do in the meantime
- Fix the wake-up time first, seven days a week. Irregular timing produces fatigue that looks exactly like a medical problem.
- Get outside in the morning.
- Move, even when you do not want to. Exercise reliably reduces fatigue in people who are inactive, which feels backwards and is well supported.
- Cut the evening alcohol for two weeks and see what changes.
- Track your actual sleep for a week. Not time in bed — the times the light went off and you got up. The gap surprises most people.
Sources. Self-help advice follows NHS guidance on insomnia, sleep and tiredness, alongside the American Academy of Sleep Medicine's recommendations. Cognitive behavioural therapy for insomnia (CBT-I) is the treatment the NHS recommends for persistent insomnia. This page is general wellbeing information, not medical advice — see a GP or doctor if sleep problems have lasted months or are affecting your daily life.
Common questions
Why am I always tired and have no energy?
The commonest explanations are not enough sleep, fragmented sleep, irregular sleep timing, stress or depression. Medical causes the NHS names include sleep apnoea, iron deficiency anaemia, thyroid problems, diabetes and ME/chronic fatigue syndrome. Several are found with a simple blood test, so persistent unexplained tiredness is worth a doctor's appointment.
Why am I so tired all the time even though I sleep enough?
If the hours are adequate, look at quality and timing: fragmented sleep, untreated sleep apnoea, alcohol, or a sleep schedule that varies a lot between weekdays and weekends. If those are fine too, it is worth seeing a GP or doctor, since fatigue is a common symptom of anaemia, thyroid disorders and depression.
When should I see a doctor about being tired?
The NHS advises seeing a GP or doctor if you have been tired for a few weeks without knowing why, if it is affecting your daily life, if it comes with other symptoms such as weight loss or mood changes, or if someone has noticed you gasping, snorting or choking in your sleep.
What is the difference between being tired and being sleepy?
Sleepy means you would fall asleep given the opportunity, which points at not enough sleep or a sleep disorder. Tired means low energy without necessarily being able to sleep, which points more towards medical causes, mood, or inactivity.
Can anxiety or stress make you tired?
Yes. Both are common causes of persistent fatigue, partly directly and partly through the disturbed sleep they cause. Depression in particular commonly presents as physical exhaustion.
Why am I tired but can't sleep?
Usually a body clock out of step with your bedtime, or the arousal that comes with stress and with worrying about sleep itself. Fatigue from a long day does not automatically come with the sleep pressure needed to fall asleep.