10 medical reasons for feeling tired

Any serious illness, especially painful ones, can make you tired. But some quite minor illnesses can also leave you feeling washed out. Here are 10 health conditions that are known to cause fatigue.

1. Coeliac disease

Is a type of food intolerance where your body reacts badly when you eat gluten, a substance found in bread, cakes and cereals. There are 250,000 diagnosed cases in the UK, but research suggests that up to 90% of sufferers don’t know they have it. Other symptoms of coeliac disease, apart from tiredness, are diarrhoea, anaemia and weight loss. Your GP can check if you have coeliac disease through a blood test.

Read more about coeliac disease.

2. Anaemia

One of the most common medical reasons for feeling constantly run down is iron deficiency anaemia. It affects around one in 20 men and post-menopausal women, but may be even more common in women who are still having periods.

Typically, you’ll feel you can’t be bothered to do anything, your muscles will feel heavy and you’ll get tired very quickly. Women with heavy periods and pregnant women are especially prone to anaemia.

Read more about iron deficiency anaemia.

3. Chronic fatigue syndrome

Chronic fatigue syndrome (also called myalgic encephalomyelitis or ME) is a severe and disabling tiredness that goes on for at least six months. There are usually other symptoms, such as a sore throat, muscle or joint pain and headache.

Read more about chronic fatigue syndrome.

4. Sleep apnoea

Sleep apnoea is a condition where your throat narrows or closes during sleep and repeatedly interrupts your breathing. This results in bad snoring and a drop in your blood's oxygen levels. The difficulty in breathing means that you wake up often in the night, and feel exhausted the next day.

It’s most common in overweight, middle-aged men. Drinking alcohol and smoking makes it worse.

Read more about sleep apnoea.

5. Underactive thyroid

An underactive thyroid gland means that you have too little thyroid hormone (thyroxine) in your body. This makes you feel tired. You’re also likely to put on weight and have aching muscles. It’s most common in women, and it happens more often as you get older.

Your GP can diagnose underactive thyroid by taking a simple blood test.

Read more about underactive thyroid.

6. Diabetes

One of the main symptoms of diabetes, a long-term condition caused by too much sugar in the blood, is feeling very tired. The other key symptoms are feeling very thirsty, going to the toilet a lot, and weight loss. Your GP can diagnose diabetes with a blood test.

Read more about diabetes.

Find your local diabetes support services.

7. Glandular fever

Glandular fever is a common viral infection that causes fatigue along with fever, sore throat and swollen glands. Most cases happen in teenagers and young adults. Usually, glandular fever symptoms clear up within four to six weeks, but the fatigue can linger for several more months.

Read more about glandular fever.

8. Depression

As well as making you feel very sad, depression can also make you feel drained of energy. And it can stop you dropping off to sleep or cause you to wake you up early in the morning, which makes you feel more tired during the day.

Read more about depression.

Find your local depression support services and your local depression self help groups.

9. Restless legs

This is when you get uncomfortable sensations in your legs, which keep you awake at night. You might have an overwhelming urge to keep moving your legs, or a deep ache in your legs, or your legs might jerk spontaneously through the night. Whatever your symptoms, your sleep will be disrupted and of poor quality, so you’ll feel very tired through the day.

Read more about restless legs.

10. Anxiety

Feeling anxious is sometimes perfectly normal. However, some people have constant, uncontrollable feelings of anxiety, which are so strong that they affect their daily life. Doctors call this generalised anxiety disorder (GAD). It affects around around one in 20 people in the UK. As well as feeling worried and irritable, people with GAD often feel tired.

Read more about anxiety.

Find your local anxiety support services.

Glandular fever

An expert explains how glandular fever is caused, how it's passed on and how to recognise the symptoms.

Last reviewed: 21/02/2013

Next review due: 21/02/2015


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Comments are personal views. Any information they give has not been checked and may not be accurate.

sowhat said on 06 April 2013

As Lynne Cook already mentioned Vitamin D deficiency is a very common cause of fatigue.

Due to the fact that the majority of people work indoors and use lots of sun screen it is being reported more often in other Northern European countries, the US and Australia.

Yet in the UK it is ignored until adults either break bones doing every day activities such as lifting a book or have a broken bone that won't heal.

If you do manage to get your GP to test your thyroid, iron and B12 levels convince them to also test your Vitamin D level otherwise you will suffer 3-5 years of misery until you break a bone.

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tinker241 said on 16 January 2013

also people who have endomestriosis who get fatigue and get tired when they are in so pain... i have that too and i do get tired a lot and feel useless when i get home from work... i cannot be bothers to do anything but i always get myself up and do things... then by the time i go to bed i crash out.. until early next morning and i do sometimes get very tired through the day... but weekends i just like to sleep at all hours...

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ann3 said on 27 December 2012

I have been suffering from extreme tirdness, all my bloods were ok apart from deficiency in vit d, my symtoms are like lynne's i hope when i start taking vit d tabs to feel much better. It is really getting me down now.

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Pussycat83 said on 13 September 2012

Where is my comment!? I made a comment suggesting narcolepsy! I suffer from it and tiredness is main symptom! I can't it is so under diagnosed & not even mentioned on this site at all! My gp couldn't even figure out what was wrong with me as all blood tests were ok, I requested the test because my dad found an article in a health mag & found out about it! It is a neurological sleep disorder meaning the problem is an in balance in the brain not the blood no blood test will diagnose it! Seriously guys, if you really struggle with staying awake during the day and nodding off all the time, or struggle with maintaining a regular sleep pattern look into it! It is very under diagnosed & often over looked by everyone!

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Pussycat83 said on 13 September 2012

I Would like to add something that has not been mentioned (which I suffer from) - a neurological sleep disorder called narcolepsy which according to wikI is just as common as parkinsons but widely under diagnosed (fewer than 1/4!) before I was diagnosed I had blood tests & tests for just about everything above but all blood tests clear & my gp couldn't find a diagnoses! It was only after my dad read an article in a health mag on narcolepsy & told me to request a test that I was diagnosed! The condition is cause by a lack of a protein in the brain called orexin (which is responsible for controlling appetite & sleep patterns). Scientists used to believe it was hereditary but now believe it could be triggered by an auto-immune response (where your immune system goes into overdrive) following a previous or temporary illness (this makes sense as I had really bad whooping cough when I was a teenager). Anyway in brief main symptoms are e.D.S (excessive daytime sleepiness & sleep attacks at inappropriate times, such as while at work & often disturbed nocturnal sleep & an abnormal daytime sleep pattern, which often is confused with insomnia), cataplexy (loss of muscle tone eg head/jaw dropping, impaired vision, legs feeling like jelly or total collapse on strong emotions such as laughter, anger, fear, surprise etc), sleep paralysis (a phenomenon in which people who are either falling asleep or awakening from sleep temporarily experience a sense of inability to move or talk), hypnagogic hallucinations (vivid, often frightening, dreamlike experiences that occur while dozing, falling asleep &/or while awakening) or automatic behaviour (where you continue to function (talking, putting things away, etc) during sleep episodes, but awakens with no memory of performing such activities). Only 20-25% of people with narcolepsy experience all symptoms so if you are constantly tired & can relate to at least 1 other thing check it out!

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UKNAN said on 31 July 2012

I have been feeling tired for a long time now, I even wake up feeling tired. I have had acid reflux for many years and recently had a hiatus hernia diagnosed and the doctor thought that may have been causing the discomfort in my chest, but as it started getting worse, I had a ct scan and now have been told I have three blocked main arteries, so this accounts for the tiredness, so often we fail to tell the doctor all our symptoms and things could be found so much earlier for us.

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02lady said on 24 May 2012

COPD - Chronic Obstructive Pulmonary Disease.
If you are a smoker or a smoker who gave up, consider whether your fatigue is accompanied by symptoms such as breathlessness. I mistook what I thought was extreme fatigue for thyroid problems, ME, leukemia etc and was tested for each. Because I thought of it as extreme tiredness - for 2 years - and described it as such, the GP never thought to check my lungs. I reached the stage where I slept in my clothes because dressing/ undressing was simply too exhausting. Finally the penny dropped with another GP and I was diagnosed with very severe COPD - I am now on Oxygen.
So if your tiredness is accompanied by shortness of breath, particularly if you wheeze or cough too, or are prone to chest infections, sinusitis etc do consider COPD. If caught early and treated appropriately youwill feel better and lead a normal life. Allowed to go unchecked it will worsen over time - particularly if you continue to smoke - until eventually you can barely function or get pneumonia. I found out too late - hence the oxygen for what is left of my life.

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WHITELIGHT said on 04 June 2011

My tiedness is very deep. I have had blood tests and the doc says they are ok. He says he carnt put a diognosis on to it because all my tests are [positive. Confusing, I feel totaly drained and no symptons of ME, or Fibromyalgia.

I must confess that iv been on Antidepressants for nearl 40 years, until last year i weened myself off them, and its been 10 months now since i last took one, maybe this is the reason of the accute tiedness, i dont know,, a change in the brains chemicals maybe.

Whatever the GP cannot put a diognosis on it, im now trying Reiki treatment so maybe it can boost some energy, and started takin Co Enzime Q 10.

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Lynne Cooke said on 21 March 2011

Deficiency in Vitamin D is also another possible culprit for chronic fatigue. Symptoms can be confused with ME and Fibromyalgia. I'm currently experiencing joint and bone pain, muscle fatigue, general fatigue, sore throat etc. I may have Fibro too but a blood test picked up a very low Vitamin D - so ask your GP for a blood test to to check this out!

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Lynne Cooke said on 21 March 2011

Deficiency in Vitamin D is also another possible culprit for chronic fatigue. Symptoms can be confused with ME and Fibromyalgia. I'm currently experiencing joint and bone pain, muscle fatigue, general fatigue, sore throat etc. I may have Fibro too but a blood test picked up a very low Vitamin D - so ask your GP for a blood test to to check this out!

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EBDOG said on 21 March 2011

Leyla I agree, I have Fibromyalgia and the tiredness is a key symptom, last night I was like a Zombie, I feel asleep putting my daughter to bed and was unable to wake properly after that, the pain wipes me out sometimes.

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