Sauna and Medications: What the Research Shows
Key insights
- A 2024 systematic review and meta-analysis of 35 studies, 353 participants and 27 different drugs found that most common medications do not measurably change core temperature during heat stress — the exceptions matter, but the list is shorter than the internet suggests 1.
- Drugs with strong anticholinergic activity raised core temperature by about 0.42 degrees Celsius at air temperatures of 30 degrees or above, alongside reduced sweating, though that finding rests largely on studies of atropine 1.
- Non-selective beta-blockers raised core temperature by a small but consistent 0.11 degrees Celsius, while antidepressants, diuretics and weakly anticholinergic drugs did not shift core temperature at all 1.
- The more practical sauna risk is not overheating but fainting afterwards: a single 30-minute session at 73 degrees Celsius lowered systolic blood pressure and it was still below baseline 30 minutes into recovery, and antihypertensives amplify that drop 2, 3.
- In a US Medicare analysis of adults aged 65 and over with chronic conditions, heatwaves were associated with a 21 to 33 per cent rise in heat-related hospitalisation across every heat-sensitising medication class studied 4.
Almost every article about sauna safety ends with the same sentence: talk to your doctor if you are on medication. It is good advice and it is also unhelpfully vague. It does not tell you which drugs actually matter, what they do to your physiology, or what a sensible protocol looks like if you are one of the very large number of adults taking a daily prescription.
The evidence base here is better than it used to be. In late 2024 a group at the University of Sydney and Penn State published the first systematic review and meta-analysis of how prescription and over-the-counter medications affect core temperature under heat stress, pooling 35 studies covering 353 individuals and 27 drugs 1. It is not a sauna study — the underlying experiments used environmental chambers and heatwave-like conditions — but the thermoregulatory challenge is the same one a sauna imposes, and the direction of the findings is instructive.
What follows is what that literature supports, what it does not, and where the real sauna-specific risk sits. This is general information rather than medical advice; nothing here replaces a conversation with the clinician who prescribed the drug.
How a medication can interfere with heat loss
In a hot room the body has two levers. It moves blood towards the skin so heat can radiate away, and it sweats so evaporation can carry heat off the surface. Both levers are under autonomic control, which is precisely where a lot of pharmacology lands.
A 2015 review in the Journal of Clinical Pharmacy and Therapeutics grouped the mechanisms into six categories: diuresis and electrolyte imbalance, sedation and cognitive impairment, altered central thermoregulation, blunted thirst recognition, reduced sweat production, and hypotension with reduced cardiac output 3. Anticholinergics block the muscarinic receptors that drive eccrine sweat glands, so the evaporative lever is weakened. Beta-blockers limit the rise in cardiac output that skin blood flow depends on. Diuretics do not change thermoregulation directly but start you further down on fluid volume, which is not a neutral position when a sauna session costs meaningful sweat losses.
That is the theory. The question the meta-analysis set out to answer is how much of it shows up as a measurable change in core temperature in a real person.
What the 2024 meta-analysis actually found
Less than the mechanistic story would predict. Across 27 drugs, the pooled evidence supported a meaningful effect for a narrow set: strong anticholinergics, non-selective beta-blockers, adrenaline, and anti-Parkinson's agents 1.
Strong anticholinergics were the clearest signal — roughly 0.42 degrees Celsius higher core temperature at ambient temperatures of 30 degrees and above, with reduced sweating alongside it. The authors were careful to flag that this estimate is carried almost entirely by atropine, which is not a drug most people take daily. Non-selective beta-blockers produced a smaller effect of about 0.11 degrees Celsius. Antidepressants, diuretics and drugs with weak anticholinergic properties did not measurably alter the core temperature response at all 1.
Two caveats deserve equal weight. The evidence quality was moderate at best, and the studies were largely conducted in younger, healthier volunteers rather than the older adults on polypharmacy who carry most of the real-world risk. A null result in a 25-year-old on one drug is not a clean bill of health for a 72-year-old on five.
The blood pressure problem is the one to take seriously
For most sauna users the realistic hazard is not hyperthermia. It is the moment you stand up.
Laukkanen and colleagues put 102 adults with at least one cardiovascular risk factor through a single 30-minute session at 73 degrees Celsius. Systolic blood pressure fell, and after 30 minutes of recovery it was still below the pre-sauna level; carotid-femoral pulse wave velocity dropped from 9.8 to 8.6 metres per second 2. For a healthy person that vasodilation is the benefit. Layered on top of an antihypertensive, a diuretic or an alpha-blocker, the same physiology becomes orthostatic hypotension, and the classic sauna syncope happens on the way out rather than on the bench.
Hannuksela and Ellahham reached the same conclusion in their 2001 American Journal of Medicine review of sauna benefits and risks: sauna bathing is well tolerated by most healthy adults, but older people prone to orthostatic hypotension should be cautious, because the post-sauna fall in blood pressure can cause fainting shortly after leaving the room 5.
What the population data adds
Chamber studies measure one drug in one controlled session. Epidemiology captures what happens to real patients. Layton and colleagues linked US Medicare claims to zip-code-level temperature data for the summers of 2007 to 2012, restricted to beneficiaries aged 65 and over with diabetes, dementia, or cardiovascular, lung or kidney disease 4.
Across every heat-sensitising drug class examined — diuretics, anticholinergics, antipsychotics, beta-blockers, stimulants and antihypertensives — heatwaves were associated with a 21 to 33 per cent increase in heat-related hospitalisation 4. Notably, the increase was broadly similar across classes, which suggests the underlying vulnerability is driven as much by age and chronic disease as by any single prescription. That is a useful corrective to drug-by-drug thinking: the person matters more than the pill.
Realistic expectations and a workable protocol
None of the above says that people on medication should avoid saunas. It says the margin for error is narrower, and that a few adjustments reclaim most of it.
Start shorter and cooler than you think you need — ten to twelve minutes at 70 to 75 degrees Celsius rather than twenty at 90 — and add duration over weeks rather than sessions. Sit up for a minute or two before standing, and do not step straight into a cold plunge if you take an antihypertensive without clearing it first. Replace fluid deliberately rather than by thirst, since several drug classes blunt thirst recognition; our piece on sauna hydration and electrolytes covers the volumes involved. Avoid alcohol entirely on sauna days. Do not sauna alone if you are on a drug with strong anticholinergic activity, a non-selective beta-blocker, or a Parkinson's medication. And bring the actual question to your prescriber: not "is sauna safe", but "does this drug affect my sweating or my blood pressure when I stand up".
Stop the session for light-headedness, nausea, palpitations, confusion or the absence of sweating in a hot room. That last one is the signal worth memorising, because it is the specific thing an anticholinergic drug takes away from you.
The Contrast Market Perspective
If your physiological margin is narrower, the accuracy of your equipment stops being a detail. A heater that overshoots its setpoint, a thermostat reading air near the ceiling rather than at bench height, or a control system without a reliable timer all push you further into a session than you intended — which is exactly what a shorter, cooler, more predictable protocol is designed to prevent. Precise temperature control and honest sensor placement are the difference between a repeatable ten minutes and an unplanned eighteen. Schedule a consultation if you would like help matching a heater and control setup to how you actually intend to use it.
References
Footnotes
- Hospers L, Dillon GA, McLachlan AJ, Alexander LM, Kenney WL, Capon A, Ebi KL, Ashworth E, Jay O, Mavros Y (2024). The effect of prescription and over-the-counter medications on core temperature in adults during heat stress: a systematic review and meta-analysis. eClinicalMedicine. PubMed ↩︎
- Laukkanen T, Kunutsor SK, Zaccardi F, Lee E, Willeit P, Khan H, Laukkanen JA (2018). Acute effects of sauna bathing on cardiovascular function. Journal of Human Hypertension. PubMed ↩︎
- Westaway K, Frank O, Husband A, McClure A, Shute R, Edwards S, Curtis J, Rowett D (2015). Medicines can affect thermoregulation and accentuate the risk of dehydration and heat-related illness during hot weather. Journal of Clinical Pharmacy and Therapeutics. PubMed ↩︎
- Layton JB, Li W, Yuan J, Gilman JP, Horton DB, Setoguchi S (2020). Heatwaves, medications, and heat-related hospitalization in older Medicare beneficiaries with chronic conditions. PLoS One. PubMed ↩︎
- Hannuksela ML, Ellahham S (2001). Benefits and risks of sauna bathing. The American Journal of Medicine. PubMed ↩︎