What does persistent fatigue feel like with immunotherapy side effects?

Persistent Fatigue is a common presentation of Immunotherapy Side Effects and may feel like exhaustion that rest does not fully relieve. You may have less stamina for washing, walking, working, or concentrating, with a heavy feeling in your body or a strong need to pause during ordinary tasks.

Immunotherapy can trigger changes in the immune system that affect more than the tumour. Fatigue may occur alongside inflammation or a hormone, lung, liver, or bowel problem, and it may also come from anaemia, poor sleep, pain, reduced food or fluid intake, or emotional strain. The sensation alone cannot identify the cause. Keep track of when it began, whether it is worsening, and which activities it prevents.

Tell your oncology team about new fatigue before your next treatment if it is persistent, limits daily activities, or feels different from your usual tiredness. Record medicines, sleep, appetite, temperature, bowel changes, breathlessness, dizziness, and muscle weakness. Use gentle activity when able, plan demanding tasks for your strongest part of the day, and ask whether blood tests or a treatment review are appropriate. Do not start supplements or steroids without medical guidance.

Contact your oncology service promptly for rapidly worsening fatigue, faintness, confusion, severe weakness, new breathlessness, chest discomfort, persistent vomiting or diarrhoea, marked thirst with frequent urination, or a high temperature. Seek emergency help for severe breathing difficulty, collapse, or inability to stay awake. These signs can reflect an immune-related problem or another condition needing assessment.

Could this fatigue be related to my immunotherapy or another treatable cause? Which symptoms should make me call the oncology team the same day? Should I change activity, fluids, or medicines while you investigate it?