Catecholamines and heart rate in female fibromyalgia patients

Abstract

Background: Fibromyalgia syndrome is a disease of unknown pathogenesis characterised by widespread chronic musculoskeletal pain. Fibromyalgia has been associated with dysregulation of the stress systems, but results are inconsistent.

Purpose: To investigate autonomic nervous system activity (urinary noradrenaline, adrenaline, dopamine, and heart rate) of fibromyalgia patients and healthy controls.

Methods: Urinary catecholamines and heart rate were assessed for a 24-hour period in a controlled hospital setting (including relaxation, a test with prolonged mental stress, and sleep), and during daily activity in 29 female fibromyalgia patients and 29 age-matched female healthy controls.

Results: With repeated measures ANOVAs, catecholamine levels were lower in patients than controls (P=.035 for noradrenaline; P=.005 for adrenaline; P=.001 for dopamine). One-way ANOVAs for the single periods showed that patients compared to controls had significantly lower adrenaline levels during the night (P=.010) and the second day (P=.010), significantly lower dopamine levels during the first day (P=.008), the night (P=.001), and the second day (P=.004). However, single time point noradrenaline levels were not significantly different between the groups. Overall, heart rate was significantly higher in patients than controls (P=.014). Specifically, significant differences emerged during relaxation (P=.016) and sleep (P=.011), but not during stress provocation or daily activities.

Conclusions: The results indicate an altered regulation of the autonomic nervous system in fibromyalgia patients, with attenuated activity of both the sympathetic (adrenal medulla component) and the parasympathetic branch.