Thyroid Dysfunction as an Underestimated Modifier of Rehabilitation Outcomes in Chronic Diseases of the Musculoskeletal System: A Hypothesis

Introduction: Chronic musculoskeletal diseases are among the leading causes of disability worldwide. However, rehabilitation outcomes can vary significantly among patients, even when standardized therapeutic protocols are applied. Traditional rehabilitation systems often focus mainly on biomechanical and structural factors, frequently neglecting systemic biological modifiers that may influence treatment responses. Emerging evidence suggests that endocrine regulation, particularly the balance of thyroid hormones, is crucial for muscle metabolism, neuromuscular function, and inflammatory pathways. Hypothesis: We hypothesize that undetected thyroid dysfunction, particularly subclinical hypothyroidism, acts as a “biological ceiling” in rehabilitation. Suboptimal thyroid levels disrupt mitochondrial energy production and inflammatory regulation, leading to decreased treatment responsiveness, persistent fatigue, and delayed functional recovery. Testing the Hypothesis: The existing literature indicates a link between thyroid dysfunction and myalgia (muscle pain), decreased mitochondrial activity, impaired neuromuscular signaling, and increased sensitivity to inflammation. Despite this, routine thyroid screening is rarely included in rehabilitation protocols, and few studies assess its impact on treatment effectiveness. Implications: We hypothesize that undetected thyroid dysfunction may lead to decreased rehabilitation responses in patients with chronic musculoskeletal diseases. Future research should explore tailored rehabilitation pathways that consider thyroid condition assessments.