%0 Journal Article %T Impact of spa therapy on physical activity, sleep and heart rate variability among individuals with fibromyalgia: Results of an ancillary study. %A Colas C %A Hodaj E %A Pichot V %A Roche F %A Cracowski C %J Complement Ther Clin Pract %V 57 %N 0 %D 2024 Jun 28 %M 38968692 %F 3.577 %R 10.1016/j.ctcp.2024.101879 %X Spa therapy is recommended to manage symptoms of fibromyalgia, but the physiological mechanisms underlying this improvement have been poorly studied. In an original study, we explored the effect of a 3-week rheumatology spa treatment for fibromyalgia patients on quality of life and with a symptom severity questionnaire. We present here the results of an ancillary study which explored three secondary criteria using objective measurement methods: diurnal actimetry for physical activity analysis, nocturnal actimetry for sleep analysis and heart rate variability. Eighty-three fibromyalgia patients were randomized to participate in an immediate 3-week rheumatological spa therapy, either a start within 6 weeks after inclusion (interventional group, n = 39) or a delayed, start 6 months after inclusion (control group, n = 44). Patients were asked to wear an actimeter (n = 56) to assess diurnal physical activity and sleep quality and a 24-h Holter ECG (n = 60) to assess nocturnal heart rate variability at baseline, 3 months and 6 months after inclusion. Time spent in sedentary and light physical activity was reduced to ∼30 min at 6 months in the interventional group (P = 0.027). Sleep quality and heart rate variability were not improved. Spa therapy made it possible to reduce sedentary activities in patients' daily life for up to 6 months afterwards, concomitant with the improvement in quality of life, pain and fatigue as highlighted in the original Thermalgi study.