Traditional Finnish saunas operate at 80–100°C and have the most extensive human evidence base for cardiovascular and longevity-associated outcomes, including large prospective cohort studies showing associations with reduced all-cause mortality. Infrared saunas operate at lower temperatures (45–60°C) using radiant heat and show promising but more limited human research. Both types activate heat shock proteins and support circulatory adaptation in healthy adults.
Key Takeaways
- Traditional Finnish saunas (80–100°C) have the strongest long-term human evidence base, including Finnish cohort studies following over 2,300 participants for up to 20 years, which reported associations between frequent sauna use and reduced cardiovascular mortality.1
- Infrared saunas operate at lower temperatures (45–60°C) by emitting far-infrared radiation that penetrates the skin directly. Early human clinical trials suggest possible cardiovascular benefits, though study sizes remain small and evidence is less established than for traditional sauna.5
- Both sauna types share core biological mechanisms: they induce heat shock protein expression, raise core body temperature, stimulate cardiovascular responses, and are proposed to act as hormetic stressors, meaning a brief controlled stress that may promote physiological adaptation.3
- A multi-arm randomized controlled trial found that adding regular sauna sessions to an exercise programme produced greater improvements in cardiorespiratory fitness and systolic blood pressure compared to exercise alone, suggesting that heat exposure may have additive cardiovascular benefits.6
- Infrared saunas are easier to install at home, require less energy, and operate at more comfortable temperatures, making them accessible to people who cannot tolerate the high heat of traditional saunas.
- For healthy adults seeking longevity-associated outcomes, three or more sauna sessions per week of 15–30 minutes is the protocol range most consistently observed across studies, irrespective of sauna type.3
- Sauna of either type is contraindicated in certain populations including pregnant women, those with unstable cardiovascular conditions, and individuals on medications affected by heat. Always consult a qualified healthcare professional before starting a sauna practice.
Chapter 1: How Sauna Works -- The Shared Biology of Heat Stress
Whatever sauna type you step into, the fundamental biological trigger is the same: an elevation of core body temperature. When the body is exposed to sustained heat, a cascade of physiological responses begins that researchers believe may explain the associations observed in long-term population studies.
Heat Shock Proteins
One of the most studied mechanisms involves a class of protective molecules called heat shock proteins (HSPs), particularly HSP70 and HSP90. These molecular chaperones are produced in response to cellular stress, including thermal stress. They help refold damaged proteins, protect cells from subsequent stressors, and are involved in inflammation regulation. Both traditional Finnish saunas and infrared saunas raise core temperature sufficiently to trigger this HSP response, though the dynamics may differ due to differences in temperature and heat delivery method.3
Cardiovascular Adaptation
Sauna bathing elicits acute cardiovascular responses that parallel those seen with moderate-intensity physical activity. Heart rate can increase from a resting level of around 60–70 beats per minute to 100–150 beats per minute during a typical Finnish sauna session. Peripheral blood vessels dilate, reducing vascular resistance and lowering diastolic blood pressure acutely. Cardiac output increases to maintain perfusion. Over repeated sessions, these acute adaptations are proposed to produce longer-term improvements in endothelial function, arterial compliance, and blood pressure regulation.3
Hormetic Stress Signalling
Hormesis describes the concept that a low-dose stressor that would be harmful at high doses can produce adaptive, beneficial responses at modest exposure levels. Heat exposure is increasingly discussed within this framework. Brief thermal challenges prompt upregulation of cytoprotective mechanisms, including antioxidant pathways and autophagy-related signalling, that may contribute to cellular resilience. This conceptual framework helps explain why regular but not excessive sauna use appears, in observational data, to be associated with favourable outcomes in healthy adults.3
With these shared mechanisms in mind, the two sauna types diverge principally in the method and efficiency of heat delivery -- and that difference has real implications for the quality and quantity of evidence available.
Chapter 2: Traditional Finnish Sauna -- The Evidence Base
The traditional Finnish sauna uses a wood-burning stove or electric heater to raise ambient air temperature to 80–100°C. Humidity is variable; users typically pour water onto hot stones to create steam bursts. This environment heats the body primarily through convection and radiation from the hot air.
The Finnish Cohort Studies
The most cited body of evidence comes from Finnish prospective cohort studies conducted by Laukkanen and colleagues. The landmark 2015 study in JAMA Internal Medicine followed 2,315 middle-aged Finnish men from the Kuopio Ischaemic Heart Disease Risk Factor Study for a median of around 20 years. The analysis examined associations between sauna bathing frequency and fatal cardiovascular and all-cause mortality events.1
Men who used the sauna four to seven times per week had substantially lower rates of fatal cardiovascular events and all-cause mortality compared with those who used the sauna only once per week, after adjustment for cardiovascular risk factors and lifestyle variables. The associations followed a frequency-dependent pattern: more frequent use was associated with progressively lower risk estimates.1
This work was later extended in a 2018 BMC Medicine study that included both men and women. Among 1,688 participants with a mean age of 63 years, frequent sauna use was again associated with reduced cardiovascular mortality and was found to improve risk prediction models for cardiovascular outcomes beyond conventional risk factors.2
Important Caveats
Several limitations deserve clear acknowledgement. Both studies are observational cohort designs. While researchers adjusted for major confounders including physical activity, alcohol use, smoking, and pre-existing conditions, residual confounding cannot be excluded. Sauna use may be a marker of broader healthy lifestyle patterns in Finnish culture rather than an independent cause of reduced mortality. A subsequent commentary explicitly noted that the association "may be noncausal," and the original authors acknowledged this possibility.1
Additionally, participants were predominantly Finnish, a population with multigenerational sauna exposure starting in childhood. Generalisability to populations with different health baselines, body compositions, or cultural practices may be limited. Long-term randomised controlled trials confirming causal benefits of traditional sauna on mortality endpoints in diverse populations do not yet exist.
A Comprehensive Review
A comprehensive review published in Mayo Clinic Proceedings in 2018 synthesised the available epidemiological, experimental, and interventional evidence on Finnish sauna bathing. The authors identified associations between sauna bathing and reduced risk of cardiovascular disease, sudden cardiac death, all-cause mortality, neurocognitive disease, and several non-vascular conditions. Proposed mechanisms included improvements in endothelial function, reduced arterial stiffness, modulation of the autonomic nervous system, and beneficial changes in lipid profiles and systemic blood pressure.3
Chapter 3: Infrared Sauna -- Emerging Human Research
Infrared saunas do not heat the air to the same temperatures as traditional saunas. Instead, they emit infrared radiation -- typically in the far-infrared spectrum (wavelengths of approximately 5–15 micrometres) -- that penetrates the skin directly and raises tissue temperature from within. Ambient cabin temperatures typically range from 45–60°C, making the experience more comfortable for many users.
Cardiovascular Research
The infrared sauna evidence base is considerably smaller and more heterogeneous than that for traditional Finnish saunas. A 2009 systematic review in Canadian Family Physician identified nine relevant human clinical studies. The review concluded there was limited moderate evidence supporting far-infrared sauna efficacy in normalising blood pressure and in supporting individuals with congestive heart failure. Fair evidence supported its use for chronic pain, and weak evidence was found for chronic fatigue syndrome and obesity. The authors found consistent fair evidence to refute claims regarding cholesterol reduction.5
A 2018 systematic review and meta-analysis in Clinical Cardiology examined sauna bath effects specifically in heart failure patients, including infrared sauna studies. The analysis reported improvements in cardiac function markers, though the authors noted that more evidence is needed regarding long-term effects, and called for larger, better-designed trials.8
Differences in Physiological Mechanism
A 2022 randomised controlled crossover trial examined how infrared sauna compares physiologically to moderate-intensity exercise in ten healthy women. The study reported that infrared sauna bathing elevated core temperature more than exercise, while exercise produced greater increases in respiratory rate. Notably, no significant differences in blood pressure, arterial stiffness, or heart rate variability were detected between infrared sauna and control conditions in the acute setting. The authors concluded that the health effects of infrared sauna appear to be driven primarily by thermoregulatory adaptations rather than exercise-mimetic cardiovascular activations.7
This finding is important context: infrared sauna likely produces its benefits through sustained thermal loading and core temperature elevation rather than through the same haemodynamic pathways triggered by high-intensity convective heat. Whether this results in equivalent long-term outcomes remains an open research question.
State of the Evidence
Compared to traditional sauna, infrared sauna research is characterised by smaller sample sizes, shorter follow-up periods, and a focus on clinical populations with existing cardiovascular conditions rather than healthy community samples. No long-term prospective cohort study comparable to the Finnish studies has been conducted specifically for infrared sauna. This does not mean infrared sauna lacks benefit -- but it does mean that confident claims about its effects on longevity-associated outcomes require more evidence than currently exists.
Chapter 4: Key Differences -- Temperature, Cost, Installation, and Accessibility
For someone evaluating which type of sauna to use or purchase, practical factors matter as much as the evidence base. The table below provides a structured comparison of the main operational and logistical differences.
| Factor | Traditional (Finnish) Sauna | Infrared Sauna |
|---|---|---|
| Operating Temperature | 80–100°C | 45–60°C |
| Heating Method | Air heated by stove or electric heater; body warmed by convection and radiation | Far-infrared radiation absorbed directly by the skin and tissue |
| Warm-Up Time | 20–45 minutes | 10–20 minutes |
| Session Duration | Typically 10–20 minutes per round (multiple rounds with cooling breaks) | Typically 20–45 minutes per session |
| Energy Consumption | Higher (wood or 220V heater) | Lower (standard household power in most units) |
| Installation Requirements | Requires dedicated space, ventilation, often 220V wiring or flue | Most units plug into standard outlet; smaller footprint options available |
| Purchase Price Range | €2,000–€15,000+ for home installation | €1,500–€8,000 (cabin units); blanket options from €300–€600 |
| Humidity Control | Adjustable via water on stones (low to high humidity) | Dry only; no steam option |
| Comfort Level | Intense; some find high heat difficult to tolerate | Milder; generally easier to tolerate for beginners |
| Evidence Base | Extensive: large cohort studies, 20+ year follow-up1,2 | Limited: smaller clinical trials, shorter follow-up5 |
For home users with limited space or budget, an infrared sauna cabin or blanket represents a lower barrier to entry. For users who prioritise maximally aligning with the studied protocols in Finnish cohort research, a traditional sauna more closely replicates the conditions under which the strongest associations have been observed.
Chapter 5: Infrared Sauna Brands -- An Educational Comparison
The consumer infrared sauna market is dominated by a small number of brands frequently cited in wellness discussions. This section provides an objective educational overview of the commonly mentioned characteristics. The Longevity Store does not endorse any particular brand, and this information should not be construed as a product recommendation.
Clearlight (Jacuzzi Saunas)
Clearlight saunas are marketed as combining true wave far-infrared and full-spectrum near/mid/far infrared technology. The brand emphasises extremely low electromagnetic field (EMF) and extremely low magnetic field (EMF/ELF) levels in its premium models, citing independent testing. Units are constructed primarily with certified clear western red cedar or basswood. Warranty coverage typically extends to the full sauna structure. Price points for cabin models generally range from approximately €3,000 to €7,000+, placing them in the premium consumer segment.
Sunlighten
Sunlighten saunas are marketed around their patented SoloCarbon technology, which delivers far-infrared heat with a stated high emissivity rate. The brand also offers a full-spectrum Mpulse range that incorporates near, mid, and far infrared at individually adjustable outputs. Sunlighten has been used in some published clinical contexts for blood pressure and weight research, though the company has an interest in those outcomes. Price points span a wide range from entry-level models to premium full-spectrum cabins, with some models exceeding €8,000.
HigherDOSE
HigherDOSE is primarily known for its infrared sauna blanket, which operates at lower price points (€300–€600) and positions itself as an accessible entry point for infrared heat therapy. The blanket format delivers far-infrared exposure but does not replicate the full-body ambient heat environment of a cabin sauna. Users report high convenience. The company also produces a traditional cabin sauna. HigherDOSE products have been notably popular in consumer wellness communities, though peer-reviewed research specifically using their equipment is not available.
Key Evaluation Criteria for Any Brand
Regardless of brand, informed consumers evaluating infrared sauna products might consider: independent third-party EMF testing results, material certifications and absence of toxic off-gassing, warranty terms and after-sales support, heater type and emissivity specifications, and verifiable customer documentation including certificate of analysis equivalents where applicable. As with supplement quality, transparency and independent verification are meaningful indicators.
Chapter 6: How to Build a Sauna Routine -- Frequency, Duration, and Safety
Translating the research into practice requires some care, as most long-term evidence comes from populations using traditional Finnish saunas according to culturally established norms rather than from controlled intervention studies setting specific protocols.
Frequency
The Finnish cohort studies suggest a dose-response pattern in which four to seven sessions per week is associated with greater longevity-related outcomes than one session per week.1 However, even two to three sessions per week showed more favourable associations compared to once per week in the same data. Joint analysis of sauna frequency and cardiorespiratory fitness found that frequent sauna bathing and high cardiorespiratory fitness together were associated with the most favourable cardiovascular and all-cause mortality risk profiles, while frequent sauna use was associated with reduced risk even in those with lower fitness levels.4
A reasonable evidence-informed starting target for otherwise healthy adults is three or more sessions per week. Those new to sauna should begin with shorter, less frequent sessions and increase gradually.
Duration
Typical session durations in the Finnish studies ranged from 15 to 30 minutes, often conducted in two rounds separated by a cooling period. The RCT examining exercise plus sauna used 15-minute post-exercise sauna sessions and demonstrated additive cardiovascular benefits versus exercise alone, suggesting that even relatively brief thermal exposure produces measurable responses.6
Hydration
Sauna use induces significant fluid loss through sweating. Adequate water intake before and after sessions is essential to avoid dehydration. Alcohol before sauna substantially increases cardiovascular risk and is strongly inadvisable. Electrolyte replacement is sensible for longer or more frequent sessions.
Contraindications and Safety
Sauna is not appropriate for everyone. Populations who should avoid sauna or consult a healthcare professional before use include: individuals with unstable or acute cardiovascular conditions, pregnant women, those taking medications that impair thermoregulation or vasodilation (including certain antihypertensives and diuretics), and people with conditions affecting heat tolerance. Age-related changes in thermoregulatory capacity may require shorter sessions for older adults. Listen to physical cues and exit immediately if you feel unwell, excessively overheated, dizzy, or uncomfortable.
Q&A Section
Is infrared sauna as effective as traditional sauna for longevity?
The existing human evidence base is substantially larger for traditional Finnish saunas, which have been studied in prospective cohorts of over 2,000 participants followed for up to 20 years.1 Infrared saunas have promising but more limited clinical evidence, primarily from smaller trials. Whether long-term use of infrared sauna produces equivalent longevity-associated outcomes to traditional sauna has not yet been directly investigated in comparable studies.
Do both types of sauna activate heat shock proteins?
Both traditional and infrared saunas raise core body temperature sufficiently to trigger heat shock protein production, which is one of the core proposed mechanisms underlying the physiological benefits of regular sauna use.3 The magnitude and kinetics of the heat shock protein response may differ between sauna types due to differences in temperature and heat delivery method.
How many times per week should I use a sauna?
Finnish cohort data suggests a frequency-dependent pattern, with four to seven sessions per week associated with more favourable outcomes than once per week.1 Even two to three sessions per week showed stronger associations than once per week in those studies. A starting target of three sessions per week is a reasonable evidence-informed benchmark for healthy adults, increased gradually from a lower starting frequency.
What are the main practical differences between the two sauna types?
Traditional saunas operate at 80–100°C and require more space and installation infrastructure. Infrared saunas operate at 45–60°C, have lower energy requirements, and are generally more compact and accessible. Traditional saunas allow humidity adjustment via water on stones; infrared saunas are dry. The milder temperature of infrared saunas makes them more tolerable for beginners or heat-sensitive individuals.
Are infrared saunas safe for cardiovascular health?
Available clinical evidence, including a systematic review of human trials, indicates that far-infrared sauna use appears to be well tolerated by individuals with stable cardiovascular conditions and may have supportive effects on blood pressure and cardiac function.5,8 However, people with unstable or acute cardiovascular conditions, or those on relevant medications, should consult a healthcare professional before use.
Can sauna replace exercise for cardiovascular health?
No. Sauna and exercise appear to have different and complementary effects. A randomised controlled trial found that adding sauna to an exercise programme produced greater improvements in cardiorespiratory fitness and systolic blood pressure than exercise alone, suggesting additive rather than substitutive benefit.6 Research comparing infrared sauna directly to exercise suggests the two activate somewhat different physiological pathways.7
What does the Finnish sauna research actually show, and what are its limitations?
The Finnish cohort studies are large, long-term prospective analyses that reported associations between frequent sauna bathing and reduced cardiovascular and all-cause mortality in Finnish populations.1,2 The principal limitation is that these are observational studies in a culturally specific population where sauna use may correlate with other healthy behaviours, making causal inference uncertain. No large randomised controlled trial has tested whether sauna use directly causes reduced mortality.
Is there a best sauna type for someone new to heat therapy?
For newcomers, infrared saunas are often more practical. Their lower operating temperatures (45–60°C) are more comfortable to acclimatise to, they require less time to warm up, and entry-level formats such as blankets are relatively affordable. Building a consistent routine is more important than sauna type, and evidence supports that even two to three weekly sessions confer greater benefit than once-weekly use.1
FAQ
What is the main difference between infrared and traditional sauna?
A traditional Finnish sauna heats the ambient air to 80–100°C, warming the body through convection. An infrared sauna uses far-infrared radiation to warm the body directly at a lower cabin temperature of 45–60°C. Both raise core body temperature, but through different delivery mechanisms, which may produce somewhat different physiological responses.
Which sauna has more scientific evidence for longevity?
Traditional Finnish saunas have a substantially larger and longer-established human evidence base, including prospective cohort studies following thousands of participants over multiple decades.1,2 Infrared saunas have smaller clinical trials with shorter follow-up periods showing promising cardiovascular effects.5 No equivalent long-term cohort study has yet been published for infrared sauna specifically.
How long should a sauna session last for health benefits?
Most of the Finnish research involved sessions of 15–30 minutes, often with one or two rounds separated by cooling periods. An RCT studying exercise plus sauna used 15-minute post-exercise sessions and reported additive cardiovascular benefits.6 For beginners, starting with 10–15 minutes and building up gradually is a sensible approach.
Is infrared sauna safe?
Published human clinical evidence indicates that infrared sauna is generally well tolerated in healthy adults and in individuals with stable cardiovascular conditions.5 Adequate hydration is important. People with unstable cardiovascular conditions, pregnancy, or medications affecting thermoregulation should consult a qualified healthcare professional before use.
Can I use sauna with supplements for longevity?
Sauna and certain supplements are sometimes combined within broader longevity lifestyle frameworks. Heat stress and some nutritional compounds may share overlapping pathways, such as activation of protective cellular mechanisms. However, no human clinical trials have directly examined the combination of specific supplements with sauna use for longevity outcomes. Sauna and supplement use are best considered as distinct, complementary lifestyle practices, each evaluated on its own evidence base.
What are heat shock proteins and why do they matter?
Heat shock proteins (HSPs) are molecular chaperones produced by cells in response to thermal and other stressors. They play roles in protein quality control, inflammation regulation, and cellular resilience. Both traditional and infrared saunas raise core temperature sufficiently to stimulate HSP production, which is proposed to be one of the mechanisms through which regular heat exposure may support long-term physiological health.3
References
- Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med. 2015;175(4):542–548. View on PubMed ↗
- Laukkanen T, Kunutsor SK, Khan H, Willeit P, Zaccardi F, Laukkanen JA. Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study. BMC Med. 2018;16(1):219. View on PubMed ↗
- Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and other health benefits of sauna bathing: a review of the evidence. Mayo Clin Proc. 2018;93(8):1111–1121. View on PubMed ↗
- Kunutsor SK, Khan H, Laukkanen T, Laukkanen JA. Joint associations of sauna bathing and cardiorespiratory fitness on cardiovascular and all-cause mortality risk: a long-term prospective cohort study. Ann Med. 2018;50(2):139–146. View on PubMed ↗
- Beever R. Far-infrared saunas for treatment of cardiovascular risk factors: summary of published evidence. Can Fam Physician. 2009;55(7):691–696. View on PubMed ↗
- Lee E, Kolunsarka I, Kostensalo J, Ahtiainen JP, Haapala EA, Willeit P, Kunutsor SK, Laukkanen JA. Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial. Am J Physiol Regul Integr Comp Physiol. 2022;323(3):R289–R299. View on PubMed ↗
- Hussain JN, Cohen MM, Mantri N, O'Malley CJ, Greaves RF. Infrared sauna as exercise-mimetic? Physiological responses to infrared sauna vs exercise in healthy women: a randomized controlled crossover trial. Complement Ther Med. 2022;64:102798. View on PubMed ↗
- Kallstrom M, Soveri I, Oldgren J, Laukkanen J, Ichiki T, Tei C, Timmerman M, Berglund L, Hagglund H. Effects of sauna bath on heart failure: a systematic review and meta-analysis. Clin Cardiol. 2018;41(11):1491–1501. View on PubMed ↗
- Laukkanen JA, Jae SY, Kauhanen J, Kunutsor SK. The interplay between systolic blood pressure, sauna bathing, and cardiovascular mortality in middle-aged and older Finnish men: a cohort study. J Nutr Health Aging. 2023;27(5):348–353. View on PubMed ↗
Disclaimer: Educational content only. Not medical advice. Supplements are not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare professional if you have a medical condition or take medication.
