Heart rate variability in patients with fibromyalgia and patients with chronic fatigue syndrome: a systematic review.
Meeus, Mira, Goubert, Dorien, De Backer, Fien et al. · Seminars in arthritis and rheumatism · 2013 · DOI
Quick Summary
This review looked at 16 studies comparing heart rhythm patterns between people with fibromyalgia, chronic fatigue syndrome, and healthy controls. Both conditions showed changes in how the heart responds to stress, but the patterns were different: fibromyalgia patients had heart rhythm problems throughout the day, while CFS patients mainly showed them during sleep. Exercise helped improve heart rhythm patterns in fibromyalgia patients.
Why It Matters
Understanding autonomic nervous system dysfunction in ME/CFS is crucial for explaining symptoms like heart palpitations, orthostatic intolerance, and abnormal stress responses. This review reveals that ME/CFS and fibromyalgia have different patterns of autonomic dysfunction, suggesting they may involve different physiological mechanisms—an important distinction for developing targeted treatments.
Observed Findings
Fibromyalgia patients showed lower heart rate variability compared to healthy controls across multiple studies.
Fibromyalgia patients demonstrated increased sympathetic nervous system activity and blunted autonomic responses to stressors.
CFS patients exhibited reduced heart rate variability primarily during sleep, not while awake.
Resistance training improved heart rate variability measurements in fibromyalgia patients.
Fibromyalgia showed more autonomic nervous system abnormalities than CFS overall.
Inferred Conclusions
The autonomic nervous system dysfunction differs between fibromyalgia and ME/CFS, with FM showing more persistent changes.
Increased sympathetic activity is a hallmark of FM but occurs only at night in CFS.
Physical exercise may partially reverse autonomic dysfunction in fibromyalgia.
Autonomic dysfunction appears to be a real physiological feature of both conditions, not merely secondary to symptoms.
Remaining Questions
Does autonomic dysfunction cause ME/CFS symptoms, or does the illness cause autonomic changes?
What This Study Does Not Prove
This review cannot establish whether autonomic dysfunction causes ME/CFS symptoms or is a consequence of the illness. It also does not prove that the autonomic changes are specific to these conditions rather than secondary to pain, deconditioning, or other factors. Direct comparative studies between FM and CFS are needed to confirm the differences observed.