Fibromyalgia (FM) is a chronic disorder defined by widespread musculoskeletal pain, while sleep apnea (SA) is a sleep disorder marked by repeated pauses in breathing during sleep. Research indicates a significant rate of co-occurrence, suggesting a shared underlying vulnerability between these conditions. This article explores the nature of this relationship, the biological factors connecting them, the challenges in diagnosis, and integrated treatment approaches.
Understanding the Connection Between Fibromyalgia and Sleep Apnea
Fibromyalgia does not directly cause the physical collapse of the upper airway that defines Obstructive Sleep Apnea (OSA). Instead, the relationship is one of co-morbidity, meaning the two conditions frequently exist together. Studies reveal a high prevalence, with up to 50% of individuals diagnosed with FM also meeting the criteria for OSA. This relationship is reciprocal: FM mechanisms can predispose a person to sleep disturbances, and SA can intensify FM symptoms. SA causes frequent, brief awakenings that prevent restorative sleep, which lowers the threshold for pain sensitivity.
Biological Factors Linking Both Conditions
A primary shared factor is central sensitization, a process where the central nervous system becomes hypersensitive, amplifying pain perception and sensory input. In people with FM, this altered pain processing leads to a lowered pain threshold and an increased reactivity to stimuli. This systemic hypersensitivity can affect the brainstem’s control over respiratory drive, potentially worsening SA episodes.
Both conditions are also characterized by significant disturbances in sleep architecture. FM patients often exhibit an alpha-delta sleep anomaly, where alpha waves intrude into the deeper, slow-wave sleep stages. This chronic sleep fragmentation prevents the body from achieving restorative rest, which exacerbates both pain and fatigue. The loss of Rapid Eye Movement (REM) sleep, often seen in coexisting SA, is also linked to increased pain sensitivity, known as hyperalgesia.
The two disorders also share a connection through systemic stress and neuroendocrine dysfunction. Both FM and SA are associated with increased sympathetic nervous system activity, the body’s “fight-or-flight” response, particularly during the night. This sustained state of arousal contributes to poor sleep quality. Chronic, low-grade inflammation and dysfunction of the Hypothalamic-Pituitary-Adrenal (HPA) axis, which regulates the stress response, are also reported in people with both conditions.
Identifying Overlapping Symptoms and Achieving Diagnosis
The co-occurrence of FM and SA presents a clinical challenge because many symptoms overlap, making it difficult to distinguish which condition is responsible for a patient’s distress. Both disorders commonly cause chronic fatigue, excessive daytime sleepiness, and cognitive difficulties, often referred to as “fibro fog.” This symptomatic overlap can lead to a delay in recognizing and diagnosing SA in someone already being treated for FM.
To accurately identify SA, a polysomnography (PSG), or comprehensive sleep study, is required. The PSG monitors breathing, oxygen levels, heart rate, and brain activity during sleep to determine the presence and severity of breathing cessations.
Given the high rate of co-morbidity, medical guidelines often recommend that all patients diagnosed with FM who report unrefreshing sleep or daytime fatigue should be screened for sleep-disordered breathing. Diagnosing both conditions is necessary because the generalized pain of FM can mask the specific symptoms of breathing cessation from SA. Untreated SA intensifies the pain and fatigue experienced by the FM patient, making accurate diagnosis essential for integrated treatment.
Treatment Approaches for Coexisting Fibromyalgia and Sleep Apnea
The management strategy for coexisting FM and SA emphasizes integrated care, as treating one condition often yields improvements in the symptoms of the other. The primary intervention for moderate to severe OSA is Continuous Positive Airway Pressure (CPAP) therapy, which uses pressurized air to keep the airway open during sleep. Effective use of CPAP reduces FM-related pain severity, improves sleep quality, and decreases fatigue by interrupting the cycle where poor sleep exacerbates pain sensitivity.
While CPAP is the standard, some FM patients may find the mask uncomfortable due to facial or jaw pain, leading to non-adherence. For these individuals, alternatives such as Mandibular Advancement Devices (MADs) may be considered to reposition the jaw and keep the airway open.
Treatments for FM, such as specific medications targeting central nervous system pain pathways and regular physical activity, can also indirectly benefit SA. Exercise and weight management are useful, as obesity is a significant risk factor for OSA. Addressing both the underlying pain mechanisms of FM and the breathing difficulties of SA offers the best prospect for reducing overall symptom burden.