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. You also have at least four of these other symptoms:

• 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

CFS is hard to diagnose. There are no tests for it, and other illnesses can cause similar symptoms. Your doctor has to rule out other diseases before making a diagnosis of CFS.

No one knows what causes CFS. It is most common in women in their 40s and 50s, but anyone can have it. It can last for years. There is no cure for CFS, so the goal of treatment is to improve symptoms. Medicine may treat pain, sleep disorders, and other problems. Lifestyle changes, coping techniques, and a special, gradual exercise program can also help.

Centers for Disease Control and Prevention