A new study is shedding some light on a mysterious illness.
The Centers for Disease Control and Prevention estimates chronic fatigue syndrome affects more than 836,000 Americans. It causes a type of debilitating fatigue that doesn't get better with rest.
A study published in The Proceedings of the National Academy of Sciences found people with chronic fatigue syndrome had substantially higher levels of certain cytokines. Those are substances from the immune system.
Researchers found that the higher the levels of certain pro-inflammatory cytokines, the more severe the symptoms of chronic fatigue syndrome.
Researchers suggest there is a link between excess inflammation and the disease.