One of the most common questions we receive is some variant of “what temperature should I set my sauna to and how long should I stay in?” The answer depends on what you are optimizing for, but it also depends on understanding what the research studies actually measured and how those measurements translate (or fail to translate) to your sauna at home.
This article covers the specific protocols used in the major studies, traditional Finnish practice, a health-optimized approach based on available evidence, and the contraindications you need to know.
What Temperature and Duration Did the KIHD Sauna Study Use?
The landmark KIHD study participants averaged 79 degrees Celsius at the thermostat with 14.2-minute sessions at a frequency of 2.1 sessions per week, though actual body-level temperatures were lower due to thermal stratification. The strongest health associations appeared at 4-7 sessions per week with durations exceeding 19 minutes.
The Kuopio Ischemic Heart Disease Risk Factor Study, which produced the cardiovascular and brain health findings we reference throughout this site, assessed sauna habits via questionnaire. Here are the parameters the participants reported:
| Parameter | Average | Range |
|---|---|---|
| Temperature (thermostat) | 79 degrees Celsius | 60-100+ degrees Celsius |
| Session duration | 14.2 minutes | 5-30+ minutes |
| Frequency | 2.1 sessions/week (overall mean) | 1-7+ sessions/week |
Why the Temperature Number Is Misleading
The 79 degrees Celsius figure is a thermostat reading, typically measured by a sensor mounted high on the sauna wall, often near the ceiling. This is important because temperature stratification in a sauna room is significant:
- Ceiling level: 90-100+ degrees Celsius
- Upper bench (head height, seated): 75-85 degrees Celsius
- Upper bench (foot level): 65-75 degrees Celsius
- Lower bench: 55-65 degrees Celsius
- Floor level: 40-50 degrees Celsius
A thermostat reading of 79 degrees Celsius likely means the participants were experiencing approximately 70-80 degrees Celsius at upper bench head height and 60-70 degrees Celsius at foot level. The thermal environment your body actually encounters is cooler than the thermostat suggests.
This matters when you try to replicate study conditions. If you set your sauna to 79 degrees Celsius on the thermostat and sit on the upper bench, you are roughly in the range the KIHD participants experienced. If you set it to 90 degrees Celsius thinking you need to exceed 79 degrees Celsius to get results, you are actually running hotter than the study population.
Session Duration Context
The average session duration of 14.2 minutes is a single continuous session. Many Finnish sauna bathers do multiple rounds (discussed below), so total time in the hot room per visit may have been 30-45 minutes with cooling breaks between rounds. The questionnaire asked about single session duration, not total visit duration, which is a limitation of the data.
The study also found that longer sessions (>19 minutes vs. <11 minutes) were independently associated with lower sudden cardiac death risk, regardless of frequency. This suggests both frequency and duration matter, though we can’t determine the relative contribution of each from observational data.
What Is the Traditional Finnish Sauna Protocol?
The traditional Finnish sauna protocol consists of 2-3 rounds of 10-20 minutes each at 80-100 degrees Celsius, with cold exposure breaks between rounds, totaling 60-90 minutes per visit. This multi-round structure with alternating heat and cold is the cultural standard refined over centuries of practice.
The traditional Finnish sauna routine has been refined over centuries and typically follows a multi-round structure:
The Three-Round Approach
Round 1: Warm-Up (10-15 minutes)
- Enter the sauna at operating temperature (80-100 degrees Celsius)
- Sit quietly on the upper bench
- Allow your body to begin sweating (usually begins at 3-5 minutes)
- Light or no water on stones (loyly)
- Purpose: gradually elevate core body temperature
Cooling Break 1 (5-15 minutes)
- Exit and cool down: cold shower, cold plunge, lake swim, or outdoor air
- Cold exposure is a central part of Finnish sauna tradition, not an afterthought
- Allow heart rate to return toward baseline
- Hydrate
Round 2: Heat Phase (10-20 minutes)
- Return to the sauna
- This is typically when loyly begins: water thrown on hot stones to create bursts of steam
- The humidity from loyly dramatically increases perceived heat (see humidity section below)
- This is the main therapeutic and social round
Cooling Break 2 (5-15 minutes)
- Cool down again
- More hydration
- Social conversation (in Finnish culture, this often takes place on the porch or changing room)
Round 3: Final Round (10-15 minutes)
- Final heat exposure, often gentler than round 2
- Some practitioners skip loyly in the final round. Others intensify it
- Purpose: one more temperature cycle before finishing
Post-Sauna Cool-Down (10-30 minutes)
- Final cold exposure
- Rest and rehydrate
- Allow core body temperature to fully normalize before dressing
Total elapsed time for a traditional Finnish sauna visit: 60-90 minutes, including cooling breaks and rest periods. Actual time in the hot room: 30-45 minutes across three rounds.
Key Points About Traditional Practice
Finnish sauna culture doesn’t treat sauna as an endurance test. Staying in until you feel dizzy, nauseous, or unable to think clearly isn’t traditional. Experienced Finnish bathers listen to their body and exit when they feel ready, without machismo about duration.
The traditional temperature range of 80-100 degrees Celsius is measured at the ceiling thermostat. Competition saunas (discussed below) far exceed this range and shouldn’t be confused with traditional practice.
How Does Loyly Humidity Affect Sauna Temperature?
Loyly (steam from water thrown on hot stones) acts as a powerful heat multiplier. 80 degrees Celsius with loyly feels significantly hotter than 90 degrees Celsius without loyly, because the humidity slows evaporative sweat cooling and increases the rate of heat transfer into the body. This is why Finnish saunas feel hotter than the thermostat reading suggests.
Understanding loyly (the steam created by throwing water on hot stones) is essential for calibrating your thermal exposure, because humidity dramatically changes the heat transfer equation.
Why Humidity Matters
The human body cools itself primarily through evaporative sweat cooling. When you sit in dry air at 80 degrees Celsius, sweat evaporates efficiently from your skin surface, providing substantial cooling. When the air is humid, evaporation slows dramatically, and the rate of heat transfer into your body increases.
The result: 80 degrees Celsius with loyly feels significantly hotter than 90 degrees Celsius without loyly. This isn’t a subjective quirk. It reflects the physics of heat transfer. For a deeper discussion of the thermodynamics, see our heat transfer article.
Practical Implications
- If you are using a sauna with minimal or no steam (dry operation, typical of many electric heaters running without water), the temperature on the thermostat gives you a reasonable approximation of thermal stress.
- If you are throwing water on stones regularly, the effective thermal load at a given thermostat temperature is substantially higher.
- This means a traditional Finnish sauna at 80 degrees Celsius with generous loyly may deliver comparable or greater physiological stress than a dry-operating infrared or electric sauna at 90-95 degrees Celsius.
When people report that “Finnish saunas feel hotter” than the thermostat suggests, this is why. The humidity from loyly is a heat multiplier.
How Do Different Sauna Protocols Compare?
Sauna protocols range from beginner-level (65-75 degrees Celsius for 8-12 minutes) to health-optimized (80-90 degrees Celsius for 15-20 minutes) to traditional Finnish (80-100 degrees Celsius in 2-3 rounds), while competition-level temperatures above 110 degrees Celsius are dangerous and have caused deaths.
| Protocol | Temperature (Thermostat) | Duration | Rounds | Steam/Loyly | Notes |
|---|---|---|---|---|---|
| KIHD Study Average | 79 degrees Celsius | 14.2 min | Not specified | Not measured | What the study participants reported |
| Traditional Finnish | 80-100 degrees Celsius | 10-20 min/round | 2-3 | Yes, moderate to heavy | The cultural standard |
| Health-Optimized | 80-90 degrees Celsius | 15-20 min | 1-2 | Optional | Based on study parameters |
| Beginner | 65-75 degrees Celsius | 8-12 min | 1 | None or light | Conservative starting point |
| Infrared Sauna | 45-60 degrees Celsius | 20-40 min | 1 | None (dry) | Different heat transfer mechanism |
| Competition Sauna (110+ degrees Celsius) | 110+ degrees Celsius | Endurance contest | 1 | Yes, extreme | Dangerous. People have died. |
A Note on Competition Sauna
The World Sauna Championships, held annually in Heinola, Finland from 1999 to 2010, pushed participants into extreme conditions: 110+ degrees Celsius with water thrown on the stones every 30 seconds. The competition was permanently discontinued after the 2010 event, when a Russian competitor died and a Finnish competitor sustained severe burns requiring months of hospitalization.
No serious sauna practitioner, Finnish or otherwise, endorses competition-level temperatures. The physiological risks at temperatures above 100 degrees Celsius with high humidity include burns to the airway and lungs, cardiovascular collapse, and organ failure. The fact that this needs to be stated explicitly reflects how distorted some corners of the sauna community have become around temperature machismo.
What Is the Best Sauna Protocol for Health Benefits?
A health-optimized sauna protocol based on research evidence is 80-90 degrees Celsius at the thermostat, 15-20 minutes per session, 3-7 sessions per week, starting conservatively and increasing gradually over 3-4 weeks. This aligns with the KIHD study parameters that showed the strongest associations with cardiovascular and longevity benefits.
Based on the KIHD study parameters and the broader sauna physiology literature, here is a reasonable protocol for someone interested in the health associations described in the research:
Session Structure
| Phase | Duration | Details |
|---|---|---|
| Pre-heat | Allow sauna to reach 80-85 degrees Celsius | 30-50 min for most electric heaters |
| Warm-up | 5 min | Sit on upper bench, no steam, acclimate |
| Heat phase | 15-20 min | Remain on upper bench, light loyly optional |
| Cooling | 2-5 min | Cold shower, cold plunge, or outdoor air |
| Optional second round | 10-15 min | Return to sauna, loyly if desired |
| Cool-down | 5-10 min | Gradual return to normal temperature |
| Hydration | Ongoing | 500ml-1L total water intake across the session |
Frequency
The KIHD data show the strongest associations at 4-7 sessions per week. However, this doesn’t mean you need to start at 7 sessions per week. The 2-3x/week group also showed meaningful (though less dramatic) benefits for hypertension, cardiovascular mortality, and other endpoints.
A reasonable progression:
- Weeks 1-2: 2 sessions per week, 10-15 minutes, 75-80 degrees Celsius
- Weeks 3-4: 3 sessions per week, 15-20 minutes, 80-85 degrees Celsius
- Ongoing: 4-5 sessions per week, 15-20 minutes, 80-90 degrees Celsius
There is no evidence that increasing beyond 7 sessions per week provides additional benefit, and the KIHD study didn’t capture data above that frequency.
Temperature Selection
For the health-associated benefits described in the literature, 80-90 degrees Celsius at the thermostat level appears to be the relevant range. This corresponds to approximately 70-80 degrees Celsius at upper bench head height in most sauna rooms.
There is no evidence that pushing to higher temperatures provides additional health benefits. The KIHD study average was 79 degrees Celsius. The dose-response data are about frequency and duration, not temperature.
If you are building or purchasing a sauna and want to align with the research parameters, aim for a unit that comfortably maintains 80-90 degrees Celsius at thermostat level. Any heater appropriately sized for your room volume will achieve this.
Who Should Not Use a Sauna?
Absolute contraindications to sauna use include recent heart attack (within 3 months), unstable angina, severe aortic stenosis, and recent stroke. Relative contraindications requiring physician consultation include stable coronary artery disease, heart failure, pregnancy, and certain medications. Alcohol and sauna should never be combined, as alcohol contributes to approximately 50% of sauna-related deaths in Finland.
Sauna bathing is remarkably safe for healthy adults when practiced within reasonable parameters. The Finnish population saunas regularly from infancy (children attend with parents from a young age), and serious adverse events are rare in the general population. However, specific conditions require caution or avoidance.
Absolute Contraindications
These conditions are considered absolute contraindications to sauna use by the Finnish Sauna Society and by the 2018 Mayo Clinic Proceedings review:
- Recent myocardial infarction (heart attack): Avoid sauna for at least 3 months following a heart attack, and resume only with physician clearance. The acute cardiovascular stress of sauna (elevated heart rate, blood pressure fluctuations, fluid shifts) poses risk to recently damaged myocardium.
- Unstable angina: Sauna can trigger anginal episodes through increased myocardial oxygen demand.
- Severe aortic stenosis: The vasodilation and reduced peripheral resistance from sauna can cause dangerous hypotension in patients with severe aortic stenosis, who can’t increase cardiac output to compensate.
- Recent stroke (within 3 months): Similar rationale to post-MI. Physician clearance required before resuming.
Relative Contraindications (Consult Your Physician)
- Stable coronary artery disease: Interestingly, the KIHD data suggest potential benefit, but this was an apparently healthy population. If you have diagnosed CAD, discuss sauna use with your cardiologist.
- Heart failure (compensated): Some small studies suggest benefit for mild-moderate heart failure (particularly the Japanese Waon therapy studies), but these used far-infrared at lower temperatures. Traditional high-temperature sauna may be too stressful.
- Pregnancy: Data are limited. The Finnish Medical Society’s guideline states that sauna is generally safe during uncomplicated pregnancy at moderate temperatures and durations, but many international guidelines recommend avoidance. Core temperature elevation above 39 degrees Celsius during the first trimester is associated with neural tube defects in animal models. Consult your obstetrician.
- Epilepsy: Risk of seizure in the hot room with associated fall/burn risk. If well-controlled, physician may approve with supervision.
- Medications that affect thermoregulation: Beta-blockers (blunt heart rate response), anticholinergics (impair sweating), diuretics (exacerbate dehydration), and vasodilators (additive hypotension risk) all require consideration. Don’t stop medications to sauna. Discuss with your prescriber.
Alcohol and Sauna
Alcohol and sauna don’t mix. This isn’t a wellness platitude. It is a safety issue. Alcohol impairs thermoregulation (reduces sweating efficiency), causes vasodilation (additive with sauna-induced vasodilation, increasing hypotension risk), impairs judgment (leading to longer sessions at higher temperatures), and is a diuretic (worsening dehydration).
In Finland, a significant proportion of sauna-related deaths involve alcohol. A 2018 analysis of sauna-related deaths in Finland found that alcohol was a contributing factor in approximately 50% of cases. The traditional practice of drinking beer in the sauna is culturally embedded but medically inadvisable, particularly for solo sauna use.
Rule: Don’t sauna while intoxicated. Period.
Children and Sauna
In Finland, children attend sauna from infancy, typically with a parent or caregiver. The Finnish Sauna Society recommends shorter sessions (5-10 minutes) and lower bench positions for children. The lower bench is significantly cooler due to temperature stratification, providing a gentler exposure.
There is no evidence of harm from moderate sauna use in healthy children. The key safety factors are supervision (never leave a child unattended in a sauna), shorter duration, lower bench position, and adequate hydration.
How Much Water Should You Drink Before, During, and After Sauna?
Drink 250-500ml of water 30 minutes before sauna, 250-500ml between rounds, and 500-750ml after the session, for a total minimum of 1,000-1,750ml per visit. Sweat rates during sauna range from 0.5 to 1.0 liters per hour, and each kilogram of body weight lost represents approximately 1 liter of fluid that needs replacement.
Sweat rate during sauna bathing varies considerably based on temperature, humidity, session duration, individual physiology, and acclimatization status. Published estimates range from 0.5 to 1.0 kg/hour (approximately 500-1,000 ml/hour).
Fluid Replacement Guidelines
| Timing | Amount | Type |
|---|---|---|
| 30 minutes before sauna | 250-500 ml | Water |
| During session (between rounds) | 250-500 ml | Water or electrolyte drink |
| Post-session | 500-750 ml | Water or electrolyte drink |
| Total minimum | 1,000-1,750 ml | Per sauna visit |
For precision, weigh yourself before and after sauna. Each kilogram of body weight lost represents approximately 1 liter of fluid. Replace 125-150% of the fluid lost (the excess accounts for ongoing losses during the rehydration period).
Electrolytes
Sweat contains approximately 0.9-2.0 grams of sodium chloride per liter. A 1-liter sweat loss during sauna means losing 0.9-2.0 grams of salt. For single sessions, water alone is adequate for most people. For multi-round sessions lasting 60+ minutes, or if you are sauna bathing in addition to heavy exercise, adding electrolytes (sodium, potassium, magnesium) is reasonable. A simple approach: a pinch of salt (approximately 1 gram) per 500 ml of water, or a commercial electrolyte mix.
What Are the Warning Signs to Leave the Sauna?
Exit the sauna immediately if you experience persistent dizziness, nausea, headache, chest pain, confusion, extreme fatigue, or muscle cramping. These indicate your thermoregulatory system is being overwhelmed and continuing risks heat exhaustion or heat stroke. Normal responses include profuse sweating, elevated heart rate (100-150 bpm), mild lightheadedness when standing, and skin reddening.
Rather than rigidly following a protocol, pay attention to your body’s signals:
Normal responses during sauna:
- Profuse sweating (begins 3-8 minutes in)
- Increased heart rate (100-150 bpm)
- Mild lightheadedness when standing (blood pooling in extremities)
- Skin reddening (vasodilation)
- Relaxation and mild euphoria
Warning signs to exit immediately:
- Dizziness that doesn’t resolve when sitting
- Nausea
- Headache
- Chest pain or palpitations
- Feeling confused or disoriented
- Extreme fatigue
- Muscle cramping (dehydration/electrolyte depletion)
If you experience any warning signs, exit the sauna, sit or lie down in a cool environment, and drink water. These symptoms indicate that your thermoregulatory system is being overwhelmed, and continuing the session risks heat exhaustion or heat stroke.
How Long Does It Take to Acclimatize to Sauna Heat?
Heat acclimatization takes 7-14 days of regular sauna exposure, during which your body develops improved sweating efficiency, expanded plasma volume, lower resting core temperature, and better subjective heat tolerance. Start conservatively with lower temperature, shorter duration, and lower bench position, then increase gradually.
If you are new to sauna or returning after a long break, your body needs time to adapt. Heat acclimatization involves:
- Improved sweating efficiency (earlier onset, higher rate, more dilute sweat)
- Expanded plasma volume (better cardiovascular reserve)
- Lower resting core temperature (more thermal headroom)
- Improved subjective heat tolerance
These adaptations occur over 7-14 days of regular exposure. Start conservatively (lower temperature, shorter duration, lower bench) and increase gradually. Most people find that sauna sessions that felt challenging in week 1 feel comfortable by week 3.
What Is the Best Sauna Temperature and Duration?
The best sauna protocol for health benefits is 80-90 degrees Celsius at the thermostat, 15-20 minutes per session, 3-7 sessions per week, based on the KIHD study where participants averaged 79 degrees Celsius and 14.2-minute sessions. Start lower and shorter if you are new, add loyly gradually, and never sauna while intoxicated.
The KIHD study participants averaged 79 degrees Celsius at the thermostat and 14.2-minute sessions. This is a moderate protocol by Finnish standards. The health associations were strongest at 4-7 sessions per week and with session durations exceeding 19 minutes.
A reasonable health-optimized protocol is 80-90 degrees Celsius, 15-20 minutes, 3-7 sessions per week. Start lower and shorter if you are new to sauna. Add loyly gradually, understanding that humidity is a powerful heat multiplier.
Respect the contraindications. Don’t sauna while intoxicated. Hydrate before, during, and after. Monitor your body’s responses and exit if warning signs appear. The goal is a sustainable, regular practice over months and years, not a single heroic session.