Why does anaemia cause fatigue?

Red blood cells contain haemoglobin, which carries oxygen from the lungs to muscles, the brain and other organs. When the blood carries less oxygen, ordinary activity can demand more effort. You may feel drained, lose stamina, or need to pause more often during tasks that previously felt manageable.

Fatigue is a very common presentation of Anaemia. It is a broad symptom, however, and can also arise from poor sleep, infection, stress, thyroid problems, medicines and many other causes. The pattern, your medical history and blood tests help a clinician work out what is contributing.

Arrange a clinical assessment if tiredness is persistent, worsening or affecting daily life. A clinician may review your diet, menstrual or other bleeding, medicines, long-term conditions and recent illness, then request a blood test. Treatment depends on the cause; iron is useful only when iron deficiency has been identified or advised.

Until you are assessed, pace demanding activities, rest when needed, eat regular nourishing meals and keep a note of symptoms such as dizziness, breathlessness or a racing heartbeat. Do not stop prescribed medicines without discussing it with the prescriber.

Seek urgent medical help for chest pain, fainting, severe shortness of breath, confusion, or a fast heartbeat that does not settle. Prompt assessment is also sensible if you notice black stools, vomiting blood, heavy bleeding, or sudden marked weakness, as these can signal blood loss or another urgent problem.

Ask what type of anaemia is suspected, which blood tests are needed, and whether bleeding, nutrition, absorption or a medical condition could be involved. You can also ask when to repeat testing and what symptoms should prompt earlier review.