Stress and relaxation affect pain modulation in people with fibromyalgia (FM) and chronic neck pain, according to a study, “Effects of Stress and Relaxation on Central Pain Modulation in Chronic Whiplash and Fibromyalgia Patients Compared to Healthy Controls,” published in the Pain Physician journal.

FM is marked by widespread muscle pain often accompanied by fatigue, sleep disturbance, mood problems, and cognitive impairment. Its underlying causes are unknown, but some hypotheses suggest that individuals with FM have a moderate threshold for pain due to increased reactivity of pain-sensitive nerve cells in the central nervous system. A similar threshold is thought to affect people with chronic neck pain caused by an injury, a condition known as chronic whiplash associated disorders (WAD).

Compelling evidence exists that impaired central pain modulation of patients with both syndromes contributes to pain. However, the influence of stress and relaxation on central pain modulation in these patients has not been well investigated.

A total of 59 participants (16 chronic WAD patients, 21 FM, and 22 pain-free controls) were included in the study. Participants underwent various pain measurements based on the temporal summation (TS) of pain and conditioned pain modulation (CPM). All were randomly assigned to receive either progressive relaxation therapy or to perform a battery of cognitive tests as cognitive stressors. They were then re-evaluated for pain and, one week later, the approaches taken were switched.

Results revealed larger differences between the groups in terms of change in TS. In response to relaxation and cognitive stress, TS decreased in patients with chronic WAD and healthy controls, but increased in FM patients. CPM efficacy reduced in all participants (FM, WAD, controls) in response to relaxation and cognitive stress.

“A single relaxation session as well as cognitive stress may have negative acute effects on pain modulation in patients with FM, while cognitive stress and relaxation did not worsen bottom-up sensitization in chronic WAD patients and healthy persons. However, endogenous pain inhibition, assessed using a CPM paradigm, worsened in chronic WAD and FM patients, as well as in healthy people following both interventions,” the authors concluded. “These results should be taken into consideration when developing therapy strategies for patients with chronic WAD and FM.”