Chronic fatigue syndrome (CFS): what to know

The fatigue is not simply ordinary sleepiness. It can substantially reduce physical, mental, or social activity, and rest may not restore usual function. Many people also notice post-exertional worsening: symptoms increase after activity and recovery takes longer than expected. Sleep that feels unrefreshing, concentration difficulty, pain, dizziness, or sensitivity to stimulation may occur.

There is no single confirming test. A clinician considers the full pattern, examines you, reviews medicines and health history, and checks for other explanations. Glandular fever, anaemia, thyroid problems, sleep disorders, low mood, and other illnesses can overlap with fatigue, so assessment should be careful rather than based on one symptom.

Arrange a GP consultation if fatigue persists, limits normal life, or is followed by a delayed worsening after activity. Before the visit, record sleep, activity, mental effort, pain, dizziness, concentration, and the time it takes to recover. This helps show patterns that may be missed in a short conversation.

Use pacing: balance activity with rest, break tasks into smaller parts, and avoid repeatedly pushing through a flare. A clinician can help with symptom management, mobility, work or study adjustments, and emotional support. Do not start a demanding exercise programme without individual guidance.

Seek urgent help for chest pain, severe breathlessness, fainting, new confusion, sudden weakness, or thoughts of harming yourself. Get prompt medical advice if you cannot maintain fluids, are rapidly deteriorating, or develop a new symptom that does not fit your usual pattern.

A new or worsening low mood deserves attention even when fatigue is the main concern. Tell your clinician about changes in mood, sleep, appetite, pain, and ability to manage basic activities.

Ask which alternative causes should be checked, whether a blood test is appropriate, how to pace activity safely, and what support is available for sleep, pain, dizziness, work, or study. Agree how follow-up will work and which changes should prompt earlier contact.