Energy & Circulation

Why am I always tired? The common causes, and where blood pressure fits.

Tiredness rarely has a single cause. Here are the ones the NHS names, in the order it makes sense to check them, plus whether blood pressure is likely to be behind it and how to tell when it’s time to see someone.

NK Medically reviewed by Dr Nouman Kazmi, MBBS FCPS ·7 min read

Key Takeaways

Tiredness usually has more than one cause. The NHS lists sleep problems, stress, depression, hormonal changes, some illnesses and some medicines.
We’d check sleep first. The NHS suggests aiming for 6 to 9 hours, at the same times each day.
Some causes can be checked with a blood test, including anaemia, an underactive thyroid and diabetes.
High blood pressure does not usually cause symptoms, so how tired you feel says very little about your blood pressure. A cuff says a lot more.
See a GP if you’ve been tired for a few weeks and don’t know why, if it affects your daily life, or if you have other symptoms.

In This Article

Start with sleep
Stress, mood and hormones
Causes a blood test can find
Heart and circulation
Does high blood pressure make you tired?
How to work out which it is
When to see a GP
Frequently asked questions
The bottom line

Start with sleep

The NHS’s list runs from not enough sleep or trouble getting to sleep to stress, depression, hormonal changes, some illnesses and some medicines, along with lifestyle habits. Sleep is where we’d start, because it costs nothing to check.

The basics are unglamorous. Aim for 6 to 9 hours of sleep and stick to the same sleep times. Relax for a couple of hours beforehand, and avoid eating, caffeine and exercise in that window. Leave screens alone for the hour before bed, and don’t smoke or drink too much alcohol. Give that a couple of weeks before you conclude that sleep isn’t the problem.

If you’re sleeping plenty and still tired, look at what happens once you’re asleep. The NHS lists tiredness in the day together with waking at night, gasping, snorting or choking noises and loud snoring as signs of sleep apnoea. That’s one to raise with a GP, not to fix with a better pillow.

6 to 9

hours of sleep is the range the NHS suggests aiming for, at the same times each day. It’s the first thing to rule out before looking further.

Stress, mood and hormones

The NHS names stress, depression and life challenges such as bereavement or looking after a new baby as causes of tiredness, and hormonal changes too, including pregnancy and the menopause. None of those is your fault.

Menopause and perimenopause can be part of this. The NHS says trouble getting to sleep or staying asleep can leave you irritable, stressed and anxious, and that symptoms may feel worse if you’re very tired. It advises contacting your GP if you think you have symptoms and want to know your options.

If your tiredness began around a bereavement, a new baby, a big change at work or the first signs of perimenopause, say so. It’s as useful to a GP as any symptom.

Causes a blood test can find

If tiredness has gone on for weeks, a GP can check for some causes with a blood test, and no number of early nights fixes a cause that isn’t sleep. Those tests can look for anaemia, diabetes or thyroid problems.

Iron deficiency anaemia. The NHS lists tiredness and lack of energy alongside shortness of breath, noticeable heartbeats, paler skin than usual and headaches. A GP confirms it with a full blood count, which checks whether your red blood cells are in the normal range.

An underactive thyroid. Feeling extremely tired and feeling cold more than usual are among the signs, with weight gain, constipation, trouble concentrating and low mood. A GP may use blood tests that check how much thyroid-stimulating hormone and thyroxine is in your blood.

Diabetes. Feeling very thirsty and peeing more often than usual are among the symptoms to watch for alongside tiredness.

If any of those sounds like you, it’s worth a conversation with a GP.

Heart and circulation

Tiredness can sometimes be a symptom of heart failure, so it helps to know what else to look for. The NHS lists feeling weak, light-headed or very tired, particularly after moving or doing physical activity, among the symptoms, alongside feeling out of breath during everyday activities or lying down, and swelling.

Being tired on its own isn’t a reason to assume heart failure. Tiredness that comes with breathlessness or swelling is a reason to see a GP rather than wait it out.

For breathlessness when lying down or from everyday activity, coughing up frothy pink phlegm or sudden weight gain, the NHS says to ask for an urgent GP appointment or get help from NHS 111. It says to call 999 for severe difficulty breathing (gasping, choking or not able to get words out), for pale, blue or grey lips or skin, or if someone has passed out and isn’t responding normally.

Does high blood pressure make you tired?

Probably not directly, and you can’t tell by how you feel. The NHS says high blood pressure does not usually cause any symptoms, and that many people have it without realising. Rarely, it can cause headaches, blurred vision or chest pain. The only way to know is a test, which means a cuff on your upper arm.

So being tired isn’t evidence that your blood pressure is high, and feeling fine isn’t evidence that it’s normal. If your blood pressure is one of the things you’re wondering about, measure it, because how the afternoon feels won’t tell you. The reason to know your number is a different one: the NHS lists long-term strain on the heart from high blood pressure as one way heart failure can develop. Our guide to measuring blood pressure correctly at home covers the technique, and our piece on the symptoms of high blood pressure covers what the NHS says to look out for.

How to work out which it is

Keep a simple note for six weeks: the hours you slept, how tired you felt each day out of ten, and a blood pressure reading at the same time each morning if you have a cuff. You’re not diagnosing yourself. You’re giving a GP something to work with, because “tired most afternoons, sleeping about six hours, readings mostly steady” gets further than “tired”. A single bad day, or a single reading, says very little, and the pattern over weeks says a lot. If it’s already been a few weeks, don’t wait for the note to fill up before you book.

The Matter BP Tracker keeps the blood pressure half of that log, so you can see the trend without a notebook.

When to see a GP

The NHS says to see a GP if:

you’ve been feeling tired for a few weeks and you’re not sure why
your tiredness affects your daily life
you feel tired and have other symptoms

There’s no drink, food or capsule that fixes tiredness when nobody knows what’s causing it. Finding the cause is the fix.

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Frequently asked questions

Why am I always tired?

Usually for more than one reason. The NHS lists not enough sleep, stress, depression, hormonal changes such as the menopause, some illnesses and some medicines. If it has gone on for a few weeks and you don’t know why, see a GP, because some causes can be checked with a blood test.

Why am I always tired even though I sleep a lot?

Sleeping a lot doesn’t rule out a cause. The NHS lists tiredness in the day together with waking at night, gasping, snorting or choking noises and loud snoring as signs of sleep apnoea. Depression is also on its list of causes, and a GP can use blood tests to check for anaemia, diabetes or thyroid problems.

What are the red flags for fatigue?

The NHS says to see a GP if you’ve been tired for a few weeks and aren’t sure why, if it affects your daily life, or if you’re tired and have other symptoms. For heart failure symptoms, it says to ask for an urgent GP appointment or get help from NHS 111 for breathlessness when lying down or from everyday activity, coughing up frothy pink phlegm or sudden weight gain. It says to call 999 for severe difficulty breathing, for pale, blue or grey lips or skin, or if someone has passed out and isn’t responding normally.

Does high blood pressure make you tired?

Not usually. The NHS says high blood pressure does not usually cause any symptoms and that many people have it without realising. So tiredness is an unreliable guide to your blood pressure, and only a reading shows it.

What is my body lacking if I am always tired?

There isn’t one answer. Iron is one the NHS names: iron deficiency anaemia causes tiredness and lack of energy, and a GP confirms it with a blood test called a full blood count. A full blood count checks whether your red blood cells are in the normal range.

What can I take or drink for tiredness?

Nothing in a glass or a capsule fixes tiredness until you know the cause. The NHS’s own advice is a healthy diet, regular exercise, the same sleep times each day, and not smoking or drinking too much alcohol. It also says not to eat or have caffeine in the couple of hours before sleep. If it carries on, speak to a GP.

Why am I always tired and have no energy as a woman?

The NHS lists hormonal changes such as pregnancy and the menopause among the causes of tiredness. Its menopause page says sleep problems can leave you irritable, stressed and anxious, and that symptoms may feel worse if you’re very tired. It advises contacting your GP if you think you have symptoms of menopause or perimenopause.

How much sleep do I need?

The NHS suggests aiming for 6 to 9 hours and trying to stick to the same sleep times each day.

The bottom line

Tiredness that lasts deserves attention, and rarely deserves panic. Start with sleep and think about stress and hormones. If it has gone on for a few weeks, a GP can check for the causes a blood test can pick up. Your blood pressure is worth knowing whatever the cause turns out to be, and a cuff is the only way to find out.

Continue Learning

References

NHS. Tiredness and fatigue. Page last reviewed 2 June 2023. Available at: nhs.uk
NHS. High blood pressure (hypertension). Page last reviewed 19 July 2024. Available at: nhs.uk
NHS. Heart failure: symptoms. Page last reviewed 26 June 2026. Available at: nhs.uk
NHS. Iron deficiency anaemia. Page last reviewed 26 January 2024. Available at: nhs.uk
NHS. Underactive thyroid (hypothyroidism): symptoms. Page last reviewed 28 April 2025. Available at: nhs.uk
NHS. Menopause: symptoms. Page last reviewed 19 May 2026. Available at: nhs.uk

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