Objective: To assess activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenocortical axis during static exercise in patients with fibromyalgia.
Patients and methods: Sixteen patients with fibromyalgia and 16 healthy controls performed a static knee extension until exhaustion. Plasma catecholamines, adrenocorticotropic hormone and cortisol, as well as blood pressure and heart rate, were assessed before, during and following contraction. Plasma C reactive protein was analysed at baseline.
• Blood pressure and heart rate increased during contraction (p < 0.001) and decreased following contraction (p < 0.001) in both groups alike.
• Compared with baseline, plasma catecholamines increased during contraction in both groups (p < 0.001),
• But patients with fibromyalgia had lower levels of plasma adrenaline (p < 0.04) and noradrenaline (p < 0.08) at all times. [The adrenal gland produces noradrenaline, a breakdown product of which is adrenaline (aka epinephrine). Adrenaline stimulates heart rate, dilates blood vessels and air passages, and generally prepares the body for fight or flight.]
• Adrenocorticotropic hormone increased at exhaustion in controls (p < 0.001), but not in patients with fibromyalgia, who also had lower adrenocorticotropic hormone at exhaustion (p < 0.02) compared with controls. [ACTH stimulates the adrenal gland to produce hormones that control blood sugar during stress.]
• There were no group differences, or changes over time in plasma cortisol. [A hormone produced by the adrenal gland that increases blood sugar during stress.]
• High sensitivity C reactive protein was higher in patients with fibromyalgia compared with controls (p < 0.02). [C reactive protein is released in response to inflammation.]
Conclusion: Patients with fibromyalgia exhibited a hypoactive sympatho-adrenal system as well as a hypo-reactive hypothalamic-pituitary axis during static exercise.
Source: Journal of Rehabilitation Medicine, Sep 2010;42(8):765-72. PMID: 20809059, by Kosek E, Kadetoff D. Osher Center For Integrative Medicine, Department of Clinical Neuroscience, Stockholm Brain Institute, Karolinska Institute, Sweden.