Balneotherapy Enhances Musculoskeletal Health and Fatigue in Post-COVID-19 Patients: Results from a Longitudinal Single Blind Randomized Trial

Background: Balneotherapy (BT) has been proposed as a supportive intervention for post-COVID-19 musculoskeletal (MSK) and fatigue-related symptoms; however, comparative evidence across different BT delivery modes remains limited. This study aimed to evaluate the long-term effects of a BT-based treatment program on MSK health and related functional outcomes in individuals with a history of COVID-19. Methods: This secondary analysis was derived from a multicenter, randomized, controlled, single-blinded trial conducted from January to September 2023 across six Lithuanian medical spa centers. Participants with a self-reported history of COVID-19 and persistent multisystem symptoms were assigned to one of three BT modalities or a control group. Primary outcomes included MSK pain, muscle tension and spasm, handgrip strength, and trunk flexibility. Secondary outcomes included fatigue, sleep, quality of life, and analgesic use. Assessments were performed at baseline, post-treatment, and at three- and six-month follow-ups. The 2-week BT program consisted of daily sessions of light pool exercise, mineral baths, sapropel body wraps, and halotherapy. Data were analyzed using repeated-measures GLM in IBM SPSS Statistics (version 28.0). Results: Significant time effects were observed for MSK pain, muscle tension, spasms, fatigue, sleep disturbance, flexibility, and quality of life (all p < 0.05). Improvements occurred primarily within groups and were most pronounced immediately post-treatment, with partial maintenance at 3–6 months. Between-group differences were modest; however, ambulatory BT, inpatient BT, and BT combined with nature therapy demonstrated greater long-term improvements in several outcomes. Conclusions: BT was associated with beneficial changes across MSK and psychosocial domains in individuals recovering from COVID-19, although differences between BT modalities were limited. These findings support BT as a complementary component within multimodal post-COVID rehabilitation frameworks and highlight the need for further research on long-term maintenance and individualized treatment strategies.