This study is a double-blinded randomized controlled trial with two arms, comparing a recorded mindfulness intervention to a control psycho-education audio. It is a monocentric study that will take place in Centre Hospitalier Universitaire Vaudois (CHUV), a primary teaching hospital in Lausanne, Switzerland.

Patients will be randomized 1:1 to the brief mindfulness intervention vs neutral audio intervention. The investigators involved in recruitment and testing will be blind to the intervention condition. A collaborator that is not involved in this study will prepare a coded randomized sequence of audio assignments, uploaded in Redcap. The audio will be played on a laptop or mp-player with a noise cancelling headset.

Inclusion Criteria:

• We plan to recruit adult female patients (>18 years old) suffering from fibromyalgia (FMS), with chronic pain (more than 6 months), willing and able to give informed consent. Specifically, patients must fulfil the criteria of the American College of Rheumatology (2010) by having the following combination of scores at the widespread pain index (WPI) and the severity score (SS) :
• WPI score is ≥7 and the SS score is ≥ 5 OR
• WPI score is comprised between 3 to 6 and the SS score ≥9
• And no other condition explaining the painful syndrome

Exclusion Criteria:

• Insufficient French language skills
• Unstable psychiatric co-morbidity: major depression with current suicidal risk, unstable psychotic disorder, unstable psychotropic medication (stable=more than 3 month under the same dose).
• Somatic co-morbidity that could interfere with physiological monitoring/stress tolerance: such as cardiac malformation, recent myocardial dysfunction, cardiac transplantation, or cardiac treatment (pacemaker, antiarrhythmic drugs, muscarinic receptor blockers, ACE inhibitors or any that would induce a modification in HR)
• Contraindication to sensors positioning (local skin damage or allergies)
• Substance use disorder (alcohol, drugs).
• Refusal to listen to an audio recording of mindfulness