Fibromyalgia is a chronic condition characterized by widespread musculoskeletal pain, fatigue, sleep disturbances, and psychological symptoms. Autonomic nervous system (ANS) dysfunction, marked by increased sympathetic and reduced parasympathetic activity, is considered one of its possible mechanisms. Although exercise is recommended in treatment, low motivation and fatigue often limit participation. Therefore, inspiratory muscle training (IMT), which targets the respiratory muscles, is seen as an easy-to-apply alternative.This randomized, controlled, double-blind study will be conducted at Niğde Ömer Halisdemir University Hospital. Fifty-one women aged 18-65 years who meet the 2010/2016 ACR criteria for fibromyalgia will be randomly assigned to three groups: training (30% of maximal inspiratory pressure), sham (0-10%), and control (no training). ANS functions will be assessed using heart rate variability and the COMPASS-31 questionnaire. Pain, sleep quality, fatigue, anxiety, depression, and respiratory muscle strength will also be evaluated. Training will be performed with the Powerbreathe® device twice daily for six weeks.The study aims to investigate the effects of IMT on ANS functions in fibromyalgia and to explore its relationship with symptoms such as pain, fatigue, sleep disturbances, anxiety, and depression.

Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain, fatigue, sleep disturbances, and psychological symptoms, the exact cause of which remains unclear. Autonomic nervous system (ANS) dysfunction, characterized by increased sympathetic activity and decreased parasympathetic tone, is considered one of the major pathophysiological mechanisms of the disease. Exercise is a strongly recommended non-pharmacological approach in the treatment of fibromyalgia; however, low motivation, fatigue, and poor adherence often limit the applicability of conventional aerobic or resistance exercise programs. Therefore, inspiratory muscle training (IMT), which specifically targets the respiratory muscles, is considered an alternative method that is easy to apply and may have regulatory effects on ANS function.

This randomized, controlled, double-blind, and prospective study will be conducted in the Rheumatology and Cardiology Clinics of Niğde Ömer Halisdemir University Training and Research Hospital. A total of 51 female participants aged 18-65 years who meet the 2010/2016 American College of Rheumatology (ACR) criteria for fibromyalgia will be randomly assigned to three groups: the training group (30% maximal inspiratory pressure [MIP]), the sham group (0-10% MIP), and the control group (no training). ANS functions will be evaluated by heart rate variability (HRV) and the COMPASS-31 questionnaire. Pain will be assessed using the Visual Analog Scale and pressure pain threshold; sleep quality by the Pittsburgh Sleep Quality Index; fatigue by the Modified Fatigue Impact Scale; anxiety and depression by the Hospital Anxiety and Depression Scale; and respiratory muscle strength by the Powerbreathe® K5 device. Training will be performed using the Powerbreathe® Classic device twice daily, seven days per week, for six weeks.

The primary aim of this study is to evaluate the effects of inspiratory muscle training on autonomic nervous system functions in patients with fibromyalgia. Secondarily, the effects of this training on symptoms such as pain, fatigue, sleep disturbances, anxiety, and depression, as well as the relationship between these symptoms and changes in ANS activity, will be investigated.

Inclusion Criteria:

• Be aged between 18 and 65 years old,
• Have been diagnosed with fibromyalgia according to the 2010/2016 ACR criteria,
• Be female,
• Have moderate pain lasting at least 3 months and defined as at least 30 mm on the 0-100 mm visual analogue scale (VAS).

Exclusion Criteria:

• Presence of chronic heart disease,
• Current use of narcotic drugs,
• History of asthma or other chronic respiratory diseases,
• Pregnancy,
• Diabetes, kidney, adrenal, pituitary or thyroid disorders,
• History of serious neurological or psychiatric disorders (e.g. mania, psychosis, suicidal tendencies, bipolar disorder, schizophrenia, autism spectrum disorders),
• Neurodegenerative diseases (e.g. Parkinson's, Alzheimer's, Huntington's disease),
• Head trauma, migraine,
• Presence of active cardiac implants.