What should you know about persistent fatigue and weakness?

Fatigue can feel like a lack of energy, while weakness means reduced muscle strength. Anaemia, infection, sleep problems, thyroid disorders, medication effects and emotional strain are possible explanations. Persistent fatigue is a common presentation of several blood cancers, including leukaemia, lymphoma, chronic lymphocytic leukaemia, multiple myeloma and myelodysplastic syndromes. It can also accompany bowel cancer. Having fatigue does not identify which condition, if any, is present.

Describe whether rest helps, whether weakness affects one side or the whole body, and whether you have breathlessness, fever, bruising, bleeding, pain, swollen glands or changes in weight. The pattern can help direct an examination and blood testing.

Book a clinical review if fatigue is persistent or worsening. Bring a list of medicines and note sleep, food and fluid intake, activity, mood and associated symptoms. Pace demanding tasks, use gentle movement if safe, and ask for help with essential activities rather than pushing through severe exhaustion. A clinician may check for anaemia and other medical causes. Blood transfusion support may be considered when a treatment team identifies a clinically significant blood-count problem; palliative care can also help manage fatigue and other symptoms during serious illness.

Seek urgent help for sudden or rapidly worsening weakness, trouble breathing, chest pain, fainting, confusion, new one-sided weakness, uncontrolled bleeding or a high fever during cancer treatment. Contact your care team promptly for new bruising, repeated infections, severe dizziness or fatigue that prevents eating, drinking or walking safely.

Ask which causes fit your symptoms, whether blood tests are needed, how activity should be paced, and which symptoms require same-day contact. If you have cancer, ask whether treatment, anaemia, sleep or pain is contributing and what support is available.