Sauna for osteoarthritis
Evidence review
Overview
No published trial has tested sauna in osteoarthritis. In a randomized trial of 93 patients with severe hip or knee OA awaiting joint replacement, 12 weeks of hot-water immersion at 104 F improved aerobic threshold and lowered resting blood pressure but did not change subjective OA severity. Uncontrolled studies of daily whole-body mud baths at 104-108 F (36 older adults with knee OA) and a 10-day course of traditional fermenting-hay baths (27 patients with OA) reported improvements in pain, stiffness and function. Systematic reviews of local heat show short-term pain relief in hand OA but no clear benefit in knee OA.
Key findings
- RCT, n=93 severe hip/knee OA: hot-water immersion at 104 F, 3x/week for 12 weeks, raised anaerobic threshold by 1.2 mL/kg/min (95% CI 0.4-1.9) but did not change subjective OA severity (p>=0.250) (Roxburgh 2024)
- Same trial: resting blood pressure fell by 9/4 mm Hg with heat therapy (p<0.001) (Roxburgh 2023)
- Uncontrolled, n=36 knee OA: 10 daily whole-body mud baths at 104-108 F improved all clinical outcomes (Gálvez 2018)
- Uncontrolled, n=27 OA: 10-day course of whole-body fermenting-hay baths lowered joint pain VAS from 2.51 to 1.83 (p<0.001) and morning stiffness from 38.9 to 17.5 minutes (p<0.05); 80% reported improvement at 6 months (Miori 1994)
- Hand OA meta-analysis (9 RCTs, n=627): local heat reduced pain VAS (SMD -0.60, p=0.01) and improved grip strength (SMD 0.43, p=0.01) short term (Cheng 2026)
- Knee OA Cochrane review (3 RCTs, n=179): hot packs had no beneficial effect on edema vs placebo or cold; evidence insufficient (Brosseau 2003)
- No sauna-specific OA trial identified
Every study we reviewed
4 found benefit · 1 found no effect · 1 mixed results
Each study was checked on PubMed. The colored edge shows the direction of the result. The research library lists 17 studies on osteoarthritis, across all heat and cold therapies, including case reports and older work not graded here.
The short-term efficacy of heat therapy for osteoarthritis of the hands: a systematic review and meta-analysis.
Cheng K et al. J Rehabil Med. 2026. PubMed 42572834 · DOI · Free full text
- Who
- Adults with hand osteoarthritis (9 RCTs)
- What
- Local heat therapy (paraffin, mud, heated gloves)
- Measured
- Pain VAS, AUSCAN pain, HAQ, grip strength
- Result
- Pain VAS SMD -0.60 (p=0.01); grip strength SMD 0.43 (p=0.01); no significant change in other outcomes; multimodal heat (paraffin, mud) outperformed pure thermal heated gloves for pain (SMD -0.85)
- Limitations
- Local, not whole-body, heat; short-term outcomes; extrapolated to sauna
Thermotherapy for treatment of osteoarthritis.
Brosseau L et al. Cochrane Database Syst Rev. 2003. PubMed 14584019 · DOI · Free full text
- Who
- Adults with knee osteoarthritis (3 RCTs)
- What
- Heat or cold therapy vs standard treatment or placebo
- Measured
- Pain, edema, range of motion, strength, function
- Result
- Hot packs had no beneficial effect on edema compared with placebo or cold; ice massage improved quadriceps strength (29% relative difference); ice packs did not significantly affect pain
- Limitations
- Only 3 small trials; local heat; review dated 2003
Upper-Limb High-Intensity Interval Training or Passive Heat Therapy to Optimize Cardiorespiratory Fitness Prior to Total Hip or Knee Arthroplasty: A Randomized Controlled Trial.
Roxburgh BH et al. Arthritis Care Res (Hoboken). 2024. PubMed 37728076 · DOI · Free full text
- Who
- Adults with severe knee or hip osteoarthritis awaiting joint replacement (New Zealand)
- What
- Hot-water immersion at 104 F (40 C) for 20-30 min then about 15 min light resistance exercise, vs upper-limb high-intensity interval training, vs home exercise
- Protocol
- 104 °F · 20-30 min · 3/wk · 12 wk
- Measured
- Peak VO2, anaerobic threshold, physical function, subjective OA severity
- Result
- Peak VO2 rose more with HIIT than heat (+2.5 mL/kg/min, 95% CI 0.5-4.4); anaerobic threshold rose with heat (+1.2 mL/kg/min, 95% CI 0.4-1.9, p=0.004); subjective OA severity unchanged with any intervention (p>=0.250)
- Limitations
- Primary aim was preoperative fitness, not OA symptoms; hot-water immersion, not sauna
Acute and adaptive cardiovascular and metabolic effects of passive heat therapy or high-intensity interval training in patients with severe lower-limb osteoarthritis.
Roxburgh BH et al. Physiol Rep. 2023. PubMed 37300374 · DOI · Free full text
- Who
- Adults with severe lower-limb osteoarthritis (same trial as Roxburgh 2024)
- What
- Hot-water immersion at 104 F (40 C) for 20-30 min then about 15 min light resistance exercise, vs HIIT, vs home exercise
- Protocol
- 104 °F · 20-30 min · 3/wk · 12 wk
- Measured
- Acute and 12-week blood pressure, glycemic control
- Result
- Resting blood pressure fell over 12 weeks with heat (systolic -9, diastolic -4 mm Hg; p<0.001) and HIIT, not home exercise; one heat session lowered systolic pressure by 12 mm Hg acutely; no change in glycemic control (p=0.310)
- Limitations
- Secondary cardiometabolic outcomes of the same trial; n not given in this abstract; hot-water immersion, not sauna
Innate/inflammatory bioregulation and clinical effectiveness of whole-body hyperthermia (balneotherapy) in elderly patients with osteoarthritis.
Gálvez I et al. Int J Hyperthermia. 2018. PubMed 30295126 · DOI · Free full text
- Who
- Elderly patients with knee osteoarthritis (Spain)
- What
- Whole-body mud bath (balneotherapy) with mineral-medicinal water and mud at a spa, daily for 10 days
- Protocol
- 104-108 °F · daily/wk
- Measured
- Knee range of motion, pain, stiffness, physical function, quality of life; IL-8, TGF-beta, regulatory T cells
- Result
- All clinical outcomes improved significantly; IL-8 and TGF-beta fell, correlating with less pain and better knee flexion
- Limitations
- Uncontrolled; mud and mineral water confound heat; spa setting; not sauna
[Critical evaluation of phytothermotherapy ("hay baths") in degenerative arthropathies].
Miori R et al. Clin Ter. 1994. PubMed 8168350
- Who
- 27 patients with osteoarthritis (15 generalized), mean age 59 +/- 8.7 years (Trentino, Italy)
- What
- Traditional Alpine 'hay bath': whole-body immersion in a bed of fermenting grass (related whole-body heat, not a sauna), 10-day course
- Protocol
- 1.5
- Measured
- Joint pain VAS, morning stiffness, grip strength, functional class, patient global assessment (immediately and at 6 months)
- Result
- Joint pain VAS 2.51 +/- 0.71 to 1.83 +/- 0.89 (p<0.001), improved in 68%; morning stiffness 38.9 to 17.5 minutes (p<0.05); grip strength 136 to 147 mm Hg (p<0.01); 48% moved to a better functional class (p<0.001); patient-rated improvement 72% immediately and 80% at 6 months
- Limitations
- Uncontrolled; Italian-language article, English abstract read; heat dose not reported; mixed joint sites; regional traditional practice
Protocols used in the studies
No sauna protocol has been tested in osteoarthritis. Whole-body heat studies used hot-water immersion at 104 F (40 C) for 20-30 minutes followed by light exercise, 3 times weekly for 12 weeks; spa mud baths at 104-108 F (40-42 C) daily for 10 days; and a 10-day course of traditional fermenting-hay baths (temperature not reported). Local heat studies used paraffin, mud, heated gloves and hot packs.
What is still unknown
Whether sauna improves pain, stiffness or function in hip, knee or hand OA has not been tested; whether the cardiovascular conditioning seen with hot-water immersion occurs with sauna in this population; whether the improvements in uncontrolled spa and hay-bath series exceed those of rest or usual care; no cohort data on sauna and OA outcomes.
Safety
Cautions for sauna in this condition
- Next-day exacerbation of rheumatic pain after sauna is reported to be more obvious in non-inflammatory than inflammatory rheumatic disease, and preventable by proper cooling (PMID 3265298).
- A single session of hot-water immersion lowered systolic blood pressure by about 12 mm Hg acutely in severe OA (PMID 37300374); orthostatic symptoms should be anticipated on exit.
- OA patients are often older with cardiovascular comorbidity; contraindications include unstable angina, recent myocardial infarction and severe aortic stenosis, and alcohol should be avoided (PMID 11165553).
- In the hay-bath series, tolerability was rated high in 23 of 25 patients; none stopped for side effects, and two needed a one-day break for asthenia (PMID 8168350).
For clinicians
Suggested rationale
There is no sauna trial in osteoarthritis. Whole-body heat by hot-water immersion improved aerobic threshold and blood pressure in patients with severe OA who cannot exercise their legs, without changing OA symptoms (Roxburgh 2024), so any rationale for sauna rests on cardiometabolic conditioning and extrapolation rather than proven joint symptom relief.
Suggested wording only. The treating clinician decides whether it reflects their clinical judgment for this patient.
Typical ICD-10 codes: M17.9, M16.9, M19.90. Examples only; the clinician assigns the code.
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