Chronic fatigue syndrome (CFS) is a disorder that causes extreme fatigue. This fatigue is not the kind of tired feeling that goes away after you rest. Instead, it lasts a long time and limits your ability to do ordinary daily activities. The main symptom of CFS is severe fatigue that lasts for 6 months or more. Other symptoms include
- Feeling unwell for more than 24 hours after physical activity
- Muscle pain
- Memory problems
- Headaches
- Pain in multiple joints
- Sleep problems
- Sore throat
- Tender lymph nodes
The causes of CFS aren’t well-understood. Some theories include viral infection, psychological stress, or a combination of factors. Because no single cause has been identified and because many other illnesses produce similar symptoms, CFS can be difficult to diagnose. There are no tests for CFS, so doctors have to rule out the other causes of your fatigue.