Clue to Chronic Fatigue

By Lisa Marshall

Women with chronic fatigue syndrome (CFS) start their day with unusually low levels of the stress hormone cortisol, according to a new study by Centers for Disease Control (CDC) researchers. The study examined saliva samples of 75 CFS patients and 110 healthy control subjects. Samples were taken upon awakening, 30 minutes later, and an hour later, when cortisol levels typically reach their highest level of the day.

While female CFS sufferers showed lower levels than their healthy counterparts, no similar difference existed among men. The study (in the Journal of Clinical Endocrinology & Metabolism) is the latest to point to a dampened “fight-or-flight” response among those with CFS. Previous research suggested it could in some cases be a physiological adaptation to physical or emotional trauma in childhood. “Accumulated stress over their lifetime may have had a muting effect on their stress response,” explains lead researcher William Reeves, MD. He says more research is underway, but the cortisol study offers clues into what causes CFS, how to diagnose and treat it, and why women are four times more likely to get it.