6 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 6 health conditions known to cause fatigue.
1. Coeliac disease
This is a type of food intolerance, where your body reacts badly when you eat gluten – a substance found in bread, cakes and cereals.
One in 100 people in the UK are affected, but research suggests up to 90% of them don't know they have the condition, according to patient group Coeliac UK.
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.
One of the most common medical reasons for feeling constantly run down is iron deficiency anaemia. It affects around 1 in 20 men and postmenopausal 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.
3. Chronic fatigue syndrome
Chronic fatigue syndrome (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.
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 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.
5. Underactive thyroid
An underactive thyroid gland means 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 happens more often as you get older.
Your GP can diagnose an underactive thyroid by taking a blood test.
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.