Heat Therapy Seems Promising for Fibromyalgia Symptoms in Small Study

Heat therapy via hot water immersion relieved symptoms and improved quality of life measures in people with fibromyalgia in a small pilot study.1

“Despite the known benefits of exercise for FM, many patients have difficult initiating or maintaining this treatment regimen due to fear avoidance of pain and rebound hyperalgesia.2 Thus, there exists is a need for a passive, non-pharmaceutical intervention that could help to reduce pain, improve physical functioning, and lead to a better quality of life,” lead investigator Andrea Chadwick, MD, MSc, associate professor, Department of Anesthesiology, Pain, and Perioperative Medicine, University of Kansas School of Medicine, and colleagues wrote.1

The study screened 62 participants and enrolled 11, all of which were female, and 3 of which withdrew, 1 for health issues unrelated to the study and 2 due to the COVID-19 pandemic. The remaining 8 participants completed the study, undergoing 4 weeks of heat therapy via hot water immersion with no adverse events.1

Investigators found that the participants’ Brief Pain Inventory (BPI) average and worst pain severity scores were significantly reduced post-intervention (P =.013 and P =.035, respectively). Participants also experienced statistically significant reductions (P = .035) in Fibromyalgia Impact Questionnaire (FIQ-R) post heat therapy and significant improvements in PROMIS Physical Function 8b questionnaire and in the PROMIS sleep-related impairment (P =.014) and PROMIS sleep-related impairment (SRI) questionnaire (P =.042), with no changes in depression or anxiety. These findings altogether demonstrated significant improvements in overall impact of fibromyalgia symptoms, physical function, and sleep-related impairment.1

Chadwick and colleagues also found a statistically significant reduction in HSP90 levels, increase in number of extracellular vesicles, and induction of HSP40 and HSC70 blood levels.

Participants reported reduced subjective pain and symptom impact, though FMness scores did not significantly change in the 8-person sample. Pressure pain threshold and tolerance values showed upward trends, but changes were not statistically significant. Conditioned pain modulation (CPM) could only be completed in 3 of 8 patients due to pain intolerance; of those, 2 showed improved CPM magnitude, though this was also not statistically significant.1

“As a whole, these findings suggest that heat therapy via hot water immersion may be an effective non-pharmaceutical intervention for patients with FM and that its analgesic benefits may be due to decreases in HSP 90 and increases in HSP 40 and 72 – which although in our study did not show significant changes in inflammatory cytokines, have been associated with improvements in inflammation. Further large-scale, well-powered studies are needed to confirm our preliminary clinical and translational results,” Chadwick and colleagues concluded.1

The investigators encouraged further research, acknowledging the study’s very small sample size as a key limitation. Another limitation was indetectable concentrations of inflammatory cytokines in serum via multiplex testing, whereas future studies should utilize an ex-vivo whole blood lipopolysaccharide stimulation model so toll-like receptor 4 global cytokine chemokine release can be scored and measured, they wrote.

REFERENCES

1. Chadwick AL, Shi C, McMillan M, Miller J, Hu J, Geiger PC. The impact of a heat therapy intervention on pain and fibromyalgia symptoms in patients with fibromyalgia: a pilot study. Front Pain Res (Lausanne). 2025;6:1526491. Published 2025 Mar 13. doi:10.3389/fpain.2025.1526491

2. Kregel KC. Heat shock proteins: modifying factors in physiological stress responses and acquired thermotolerance. J Appl Physiol (1985). (2002) 92(5):2177–86. 10.1152/japplphysiol.01267.2001