Sauna for chronic kidney disease
Evidence review
Overview
In the KIHD cohort, frequent sauna bathing was not associated with incident CKD or with worse renal function measures, which is mainly reassuring about safety. In a randomized crossover pilot in stage G2-G4 CKD, a single 25-minute far-infrared sauna session improved flow-mediated dilation and 6-minute walk distance acutely without changes in kidney injury markers. A small open-label pilot used a portable sauna to reduce fluid overload in peritoneal dialysis patients, and a two-centre hemodialysis pilot found lower interdialytic weight gain with home hot-water baths and lower predialysis potassium and urea with hammam visits. No trial has tested repeated sauna sessions on kidney or cardiovascular outcomes in CKD.
Key findings
- KIHD (n=2,071 men with normal kidney function, 25.7-year follow-up): CKD HR 0.84 (95% CI 0.46-1.53) for 4-7 vs 1 session/week (no association).
- Crossover RCT in CKD G2-G4 (n=10): FMD 6.68% after sauna vs 3.84% after control (P<0.01); no change in kidney function or acute kidney injury biomarkers.
- Peritoneal dialysis pilot: overhydration 6.3 to 5.5 L (p=0.05) and DBP 92 to 83 mmHg (P=0.003); adverse events in 3 of 54 sessions, including a second-degree burn.
- Hemodialysis pilot (n=14): 4 hot-water baths/week for 1 month lowered interdialytic weight gain 2.3 to 1.8 kg (P=0.004) and antihypertensive use (2.8 to 1.9 drugs, P=0.01) in 5 patients; hammam visits lowered predialysis potassium 5.9 to 5.5 mmol/L (P=0.04) in 9 (Pruijm 2013).
Every study we reviewed
1 found no effect · 2 found benefit · 1 mixed results
Each study was checked on PubMed. The colored edge shows the direction of the result. The research library lists 23 studies on kidney disease and dialysis, across all heat and cold therapies, including case reports and older work not graded here.
Sauna bathing, renal function and chronic kidney disease: Cross-sectional and longitudinal findings from the KIHD study.
Kunutsor SK et al. Eur J Clin Invest. 2023. PubMed 37029766 · DOI · Free full text
- Who
- Finnish men aged 42-61 with normal kidney function (KIHD)
- What
- Self-reported sauna frequency 4-7 vs 1 session/week
- Protocol
- 1 vs 4-7/wk
- Measured
- Incident CKD; eGFR, creatinine, K, Na
- Result
- 188 CKD cases; HR 0.84 (95% CI 0.46-1.53; p=.56) for 4-7 vs 1 session/week. No significant difference in baseline eGFR, creatinine or Na; serum K +0.05 mmol/L (95% CI 0.00-0.10).
- Limitations
- Observational; men without CKD at baseline; primarily informative about safety rather than treatment.
Acute effects of passive heat exposure on vascular function and exercise capacity in patients with chronic kidney disease.
Chavez DA et al. Am J Physiol Heart Circ Physiol. 2026. PubMed 42113470 · DOI · Free full text
- Who
- Adults with CKD stage G2-G4 (mean age 41, mean eGFR 55)
- What
- Single far-infrared sauna session vs thermoneutral control, randomized crossover
- Protocol
- 140 °F · 25 min · single session/wk
- Measured
- FMD, leg blood flow to passive limb movement, 6MWD, urinary kidney injury markers
- Result
- FMD 6.68% vs 3.84% (P<0.01); leg blood flow AUC 243 vs 179 (P=0.01); 6MWD 670 vs 632 yards (P<0.01); no significant changes in kidney function or AKI biomarkers.
- Limitations
- Acute single session; very small pilot; young CKD sample.
Portable sauna stimulated-diaphoresis for the treatment of fluid-overload in peritoneal dialysis patients: A pilot study.
Maggiani-Aguilera P et al. Front Med (Lausanne). 2022. PubMed 36203760 · DOI · Free full text
- Who
- Patients on continuous ambulatory peritoneal dialysis with fluid overload (Mexico)
- What
- Portable sauna bath daily for 10 days (stimulated diaphoresis)
- Protocol
- 113 °F · 30 min · daily/wk · 10 days
- Measured
- Adverse events; overhydration, weight, BP, sleep quality
- Result
- 51 of 54 sessions well tolerated; overhydration 6.3 to 5.5 L (p=0.05); weight 67.7 to 66.8 kg (p=0.003); DBP 92 to 83 mmHg (P=0.003); PSQI 7.3 to 5.1 (p=0.02).
- Limitations
- Open-label, uncontrolled comparison with a control period; very small (patient number not stated in abstract); portable sauna at low temperature.
Stimulated sweating as a therapy to reduce interdialytic weight gain and improve potassium balance in chronic hemodialysis patients: a pilot study.
Pruijm M et al. Hemodial Int. 2013. PubMed 23013432 · DOI
- Who
- Chronic hemodialysis patients in Lausanne (n=5 men, median age 55) and Sfax (n=9, median age 46)
- What
- Hot-water baths, mean 106.2 F (41.2 C), 30 min, 4 times/week on non-dialysis days for 1 month (Lausanne), or hammam visits 4 times/week for 1 month (Sfax); each compared with a preceding 1-month control period
- Protocol
- 106.2 °F · 30 min · 4/wk · 4 wk
- Measured
- Interdialytic weight gain, blood pressure, antihypertensive use, serum potassium and urea
- Result
- Baths: interdialytic weight gain 2.3 to 1.8 kg (P=0.004), systolic BP 139 to 136 mmHg (P=0.4), diastolic 79 to 75 mmHg (P=0.08), antihypertensive drugs 2.8 to 1.9 per patient (P=0.01); sweat loss about 600 g per bath. Hammam: no change in weight gain or BP, but predialysis potassium 5.9 to 5.5 mmol/L (P=0.04) and urea 26.9 to 23.1 mmol/L (P=0.02).
- Limitations
- 14 patients at two centres with different methods; before-after comparison with a preceding control month; 1 month only.
Protocols used in the studies
Acute crossover: 140 F (60 C) far-infrared sauna for 25 min. Peritoneal dialysis pilot: portable sauna at 113 F (45 C) for 30 min daily for 10 days. Cohort: habitual Finnish sauna use. Hemodialysis pilot: hot-water baths at about 106 F (41 C) for 30 minutes, or hammam visits, 4 times a week on non-dialysis days for 1 month.
What is still unknown
Effect of repeated sauna sessions on blood pressure, vascular function, cardiovascular events or kidney function in CKD; safety in advanced CKD, hemodialysis and kidney transplant recipients; role of sauna-induced diaphoresis for volume management. Reports of sauna-induced sweating in chronic renal failure and dialysis from 1966-1982 have no abstracts on PubMed and were not reviewed. Far-infrared lamps applied to an arteriovenous fistula, the abdomen or the feet of dialysis patients are local devices, a different modality not covered here.
Safety
Cautions for sauna in this condition
- Serum potassium was marginally higher with frequent sauna use in the KIHD cross-sectional analysis (+0.05 mmol/L; PMID 37029766); plasma creatinine rose slightly after a 30-min sauna in adults with CV risk factors (PMID 29269746).
- In a peritoneal dialysis pilot, transient dizziness occurred in two sessions and a second-degree skin burn in a patient with advanced diabetic neuropathy (PMID 36203760).
- Sweat-induced volume loss may matter in patients prone to volume depletion or on diuretics (clinical consideration; not tested in the cited studies).
- Sweating removed about 600 g per hot-water bath in hemodialysis patients (PMID 23013432); in dialysis patients, fluid and blood-pressure changes call for supervision and coordination with the dialysis team.
For clinicians
Suggested rationale
Long-term cohort data suggest frequent sauna bathing is not associated with incident CKD (Kunutsor 2023), and a pilot crossover trial showed acute vascular and exercise-capacity improvements without kidney injury in stage G2-G4 CKD (Chavez 2026); evidence for therapeutic benefit remains preliminary.
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Typical ICD-10 codes: N18.30, N18.4, N18.9, Z99.2, N18.6. Examples only; the clinician assigns the code.
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