Tiredness that does not improve with rest is one of the most common reasons people see a doctor, and it often has a treatable cause.
See a doctor if
- Tiredness has lasted several weeks without improvement
- It comes with weight loss, fever or night sweats
- You are also breathless or look pale
- It is affecting your ability to work or care for yourself
- You have new low mood, or thoughts of harming yourself — seek help promptly
Common causes
These are causes doctors commonly see. This list cannot tell you which one applies to you.
- Iron deficiency anaemia
- Hypothyroidism
- Uncontrolled diabetes
- Poor or insufficient sleep, including sleep apnoea
- Depression and anxiety
- Vitamin B12 or vitamin D deficiency
- Chronic infection such as tuberculosis
Frequently Asked Questions
Why am I always tired even after sleeping enough?
Tiredness that rest does not fix often has a treatable medical cause. The common ones are iron deficiency anaemia, an underactive thyroid, uncontrolled diabetes, vitamin B12 or vitamin D deficiency, sleep apnoea, and depression. Most are found with straightforward blood tests.
Which tests are usually done for constant tiredness?
A doctor will typically start with a complete blood count to look for anaemia, a thyroid test, a blood sugar test, and sometimes vitamin B12 and vitamin D. Which ones you need depends on your history and examination, so the list is a starting point rather than a shopping list.
When should tiredness be checked by a doctor?
See a doctor if it has lasted several weeks without improving, if it comes with weight loss, fever or night sweats, if you are also breathless or look pale, or if it is affecting your ability to work or look after yourself. If you have new low mood or thoughts of harming yourself, seek help promptly.
What to do next
Note when the symptom started, how it has changed, and anything that makes it better or worse. Take that information — and a list of your medicines — to your doctor. It makes the consultation considerably more useful than trying to recall it on the spot.
If any of the warning signs above apply to you, do not wait for an appointment. Go to a hospital, or call 112.