What Is Chronic Fatigue Syndrome?

Chronic fatigue syndrome (CFS) is a disease that causes you to become so fatigued (tired) you can't perform normal daily tasks. This is called chronic fatigue. The main symptom of CFS is chronic fatigue that lasts more than 6 months. Physical or mental activity often make the symptoms worse, and rest usually doesn't improve the symptoms.

CFS is complicated and difficult to diagnose. Some people have a hard time accepting CFS as a disease. It's important to remember that your fatigue is real and that you can work with your doctor to improve your symptoms.