New study sheds light on importance of stress systems and physical activity in fibromyalgia

Changes in areas of the brain and amount of physical activity both contribute to levels of fatigue experienced by women with fibromyalgia, says a small study in the Journal of Psychosomatic Research.Fibromyalgia is a long-term condition that causes pain all over the body but we don’t yet know what causes it. Fatigue is one of its defining, and most debilitating, symptoms.

A team of experts decided to test if stress-related biological processes and physical activity impact on fatigue in 26 women with fibromyalgia. The women reported general, mental and physical fatigue levels at six time points a day for 14 consecutive days.

Levels of cortisol (a stress hormone) and alpha-amylase (an enzyme that correlates with stress levels) in the saliva were measured. The volunteers wore wrist actigraphs to assess their physical activity.

Key findings included:

• Lower increases in cortisol after awakening predicted higher average physical fatigue levels;
• The more active a person was, the less tired they felt the next day;
• Levels of physical fatigue at a specific time point were positively associated with momentary cortisol levels;
• The increase in cortisol after awakening did not mediate the relationship between physical activity and fatigue;
• There were no associations between alpha-amylase and fatigue.

“Our findings imply that both changes in hypothalamic-pituitary-adrenal axis activity and physical activity contribute to variance in fatigue in the daily lives of patients with fibromyalgia syndrome,” the authors say. “This study helps to paint a clearer picture of the biological and behavioral underpinnings of fatigue in fibromyalgia syndrome and highlight the necessity of interdisciplinary treatment approaches targeting biological, behavioral and psychological aspects of fibromyalgia syndrome.”

Click here to read the original research.

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