Fatigue: is tiredness a sign of leukaemia?
Persistent tiredness that doesn’t improve with rest can sometimes be a sign of leukaemia.
At a glance
- Persistent Fatigue is one of the most common symptoms of leukaemia
- Leukaemia related fatigue is often persistent and doesn’t improve with rest or sleep
- In most cases, fatigue will not be caused by leukaemia, but persistent or unexplained tiredness should always be checked by a GP
- When you see your GP, ask specifically for a full blood count test
What is leukaemia fatigue?
Feeling tired from time to time is common and is usually caused by everyday factors such as stress, poor sleep, or minor infections. But persistent fatigue, tiredness that doesn’t improve with rest or sleep, can sometimes be a sign of an underlying condition, including leukaemia.
Fatigue is one of the most commonly reported symptoms of leukaemia and blood cancer. It can develop gradually and is often easy to dismiss or put down to other causes, which is why it sometimes goes unnoticed before a diagnosis is made.
👉 Learn more about the signs and symptoms of leukaemia
Leukaemia fatigue vs normal tiredness
Normal tiredness usually has a clear cause and tends to improve with rest or sleep. Leukaemia fatigue is different. Some people describe it as a bone-deep exhaustion that sleep doesn’t fix. It often:
- Doesn’t improve with rest or sleep
- Has no obvious cause
- Gets worse over time rather than improving
- Affects your ability to carry out everyday activities
- Occurs alongside other symptoms such as pale skin, unexplained bruising or bleeding, or frequent infections
Why does leukaemia cause fatigue?
Leukaemia starts in the bone marrow, where blood cells are made. When leukaemia develops, abnormal white blood cells multiply rapidly and crowd out the healthy blood cells, including red blood cells. Red blood cells carry oxygen around the body, so when there are too few of them, the body has to work harder to function normally. This leads to anaemia, which causes the persistent, overwhelming tiredness that many people with leukaemia experience.
Unlike fatigue from a poor night’s sleep or a busy period at work, leukaemia related fatigue is caused by a physical shortage of oxygen reaching your muscles and organs. This is why it doesn’t improve with rest, and why it can be accompanied by other symptoms of anaemia such as pale skin, shortness of breath, and dizziness.
Janev’s story
Janev’s fatigue set in during September 2023. As a primary school teaching assistant, she initially attributed her tiredness to the demands of the role. But the exhaustion eventually reached a point where she found herself cancelling plans with friends and stepping back from her regular fitness activities.
When should you see a GP about fatigue? 👩🏽⚕️
You should consider contacting your GP if your tiredness:
- Lasts for several weeks
- Is unusual for you
- Is getting progressively worse
- Occurs together with other symptoms such as unexplained bruising or bleeding, frequent infections, night sweats, or unintentional weight loss
When you see your GP, ask specifically for a full blood count test. This is a simple blood test that can help identify whether an underlying condition may be causing your symptoms. In most cases, fatigue will not be caused by leukaemia but persistent or unexplained tiredness should always be checked.
Frequently asked questions about leukaemia and fatigue?
No. Fatigue is very common and has many possible causes, including poor sleep, stress, anaemia from iron deficiency, and viral infections. In most cases it will not be caused by leukaemia. However, if your fatigue is persistent, unexplained, or occurs alongside other symptoms, speak to your GP and ask for a full blood count test.
People diagnosed with leukaemia often describe it as a bone-deep exhaustion that feels very different from ordinary tiredness. It’s persistent, whole body, and impossible to shake off even after a full night’s sleep. It may also occur alongside pale skin, weakness, or shortness of breath.
Normal tiredness usually has a clear cause and tends to improve with rest or sleep. Leukaemia fatigue is different. Some people describe it as a bone-deep exhaustion that sleep doesn’t fix. It often:
- Doesn’t improve with rest or sleep
- Has no obvious cause
- Gets worse over time rather than improving
- Affects your ability to carry out everyday activities
- Occurs alongside other symptoms such as pale skin, unexplained bruising or bleeding, or frequent infections
In leukaemia, fatigue tends to persist and worsen over time rather than coming and going the way ordinary tiredness does. It will not resolve on its own without treatment of the underlying cause. If you have been feeling unusually tired for several weeks with no clear explanation, speak to your GP.
It can, particularly if leukaemia is undiagnosed or untreated. This is one of the features that distinguishes it from everyday tiredness, which typically fluctuates and improves with rest.
It can, particularly in the early stages or in slower growing types such as chronic lymphocytic leukaemia (CLL). If fatigue is your only symptom but it is persistent or unusual for you, it is still worth speaking to your GP.
Disclaimer: While we are able to highlight the common signs and symptoms of leukaemia, these symptoms are often caused by other medical conditions. As a charity we are not able to give specific medical advice to patients, but if you have any concerns contact your GP.
Last reviewed: June 2026