Infrared vs Traditional

How Finnish sauna, infrared sauna, and steam rooms compare in temperature, mechanisms, and health outcomes

Not all saunas are created equal. Finnish-style saunas, infrared cabins, and steam rooms each deliver heat to the body through different mechanisms and at different intensities — and these differences matter when you look at the research. The vast majority of long-term health outcome data comes from traditional Finnish sauna studies, where temperatures reach 80-100°C and sessions of 15-20 minutes produce deep cardiovascular stress [1]. Infrared saunas operate at much lower air temperatures (45-60°C) but use radiant energy to penetrate tissue more directly, while steam rooms rely on humid heat at moderate temperatures [5]. Each has legitimate uses, but the evidence base is not equally deep.

How They Work: Three Different Heating Strategies

Finnish (dry) sauna heats the air in an enclosed room to 80-100°C using a wood, electric, or gas-fired stove, often with rocks on which water is poured to create brief bursts of steam (löyly). The air itself is the primary heat vector. Your body absorbs heat from the hot air through convection and radiation, raising core temperature by 1-2°C over a typical 15-20 minute session [2]. This produces profound cardiovascular demand — heart rates of 100-150 beats per minute — and heavy sweating of 0.5-1 liter per session [5].

Infrared sauna uses panels that emit infrared radiation in the far-infrared (FIR) spectrum, typically at wavelengths of 3-100 micrometers. Rather than heating the air, infrared energy penetrates the skin by approximately 1.5-4 centimeters and heats tissue directly [5]. Air temperatures stay much lower — usually 45-60°C — making the experience more tolerable for people who find traditional sauna oppressive. Core temperature still rises, but typically less dramatically, and sweat onset occurs more gradually. Sessions tend to run 20-30 minutes.

Steam rooms operate at 40-50°C with near 100% humidity. The high moisture content makes the heat feel more intense than the temperature suggests, because sweat cannot evaporate efficiently. Steam rooms produce heavy sweating but through a different thermoregulatory mechanism — the body's cooling system is essentially overwhelmed by humidity rather than challenged by extreme dry heat. There is very little controlled research on steam rooms specifically, so most health claims are extrapolated from general heat exposure studies.

What the Finnish Studies Actually Show

The strongest evidence for sauna and long-term health outcomes comes from Finnish cohort studies involving traditional dry sauna at high temperatures [1][4]. In the landmark Kuopio Ischemic Heart Disease (KIHD) study of 2,315 men followed for over 20 years, those using sauna two to three times per week had a 27% lower risk of cardiovascular mortality compared to once-weekly users. At four to seven sessions per week, cardiovascular mortality risk dropped by 50% [1]. These findings were later extended to include women, with consistent dose-response patterns [4].

The cardiovascular adaptations driving these outcomes — improved endothelial function, reduced arterial stiffness, lower resting blood pressure — appear to require the intense hemodynamic stress produced by high-temperature sauna [4][5]. Whether lower-temperature infrared sauna produces the same degree of cardiovascular conditioning over decades is simply not known, because no comparable long-term cohort studies exist for infrared.

Where Infrared Has Its Own Evidence

Infrared sauna research, while less extensive, is not without substance. A controlled trial in patients with rheumatoid arthritis and ankylosing spondylitis found that infrared sauna sessions produced significant short-term reductions in pain and stiffness, with no disease worsening [3]. The lower air temperature made it accessible to patients who could not tolerate traditional sauna.

Infrared sauna has also shown promise for improving endothelial function and cardiac output in patients with congestive heart failure — a population for whom traditional high-temperature sauna would be contraindicated [5]. These clinical applications may represent infrared's most important niche: delivering heat therapy to people who cannot safely tolerate the extreme conditions of a Finnish sauna.

For healthy adults seeking the broadest evidence-backed benefits, traditional Finnish sauna at 80-100°C remains the most supported choice. But infrared offers a legitimate, lower-intensity alternative with its own emerging evidence base — particularly for pain management, joint conditions, and populations with cardiovascular limitations.

Evidence Review

Finnish Cardiovascular Mortality Data (Laukkanen et al., 2015)

The KIHD prospective cohort study remains the gold standard for sauna and hard health outcomes [1]. Among 2,315 middle-aged Finnish men followed for a median of 20.7 years, sauna frequency showed a clear dose-response relationship with cardiovascular mortality. Compared to once-weekly users, those bathing two to three times per week had a 27% lower risk of fatal cardiovascular events (HR 0.73, 95% CI 0.58-0.92), and those bathing four to seven times per week had a 50% lower risk (HR 0.50, 95% CI 0.33-0.76). These sessions were conducted in traditional Finnish saunas at approximately 80°C or higher. The study did not include infrared or steam room users, meaning these specific risk reductions cannot be directly attributed to other sauna types.

Systematic Review of Dry Sauna (Hannuksela & Ellahham, 2001)

This systematic review synthesized available clinical evidence for traditional dry sauna use across cardiovascular, respiratory, and musculoskeletal outcomes [2]. The authors documented that Finnish-style sauna produces acute hemodynamic changes including increased cardiac output, decreased peripheral vascular resistance, and transient blood pressure reduction. Chronic adaptations in regular users included improved arterial compliance and reduced resting blood pressure. The review noted that sauna bathing appeared safe for stable cardiovascular patients and beneficial for conditions including chronic heart failure (at appropriate temperatures) and chronic pain syndromes. The authors highlighted the importance of adequate hydration and alcohol avoidance, and identified the lack of randomized controlled trials as a major limitation of the evidence base.

Infrared Sauna for Inflammatory Joint Disease (Oosterveld et al., 2009)

This controlled clinical study examined the effects of infrared sauna on patients with rheumatoid arthritis (n=17) and ankylosing spondylitis (n=17) [3]. Participants underwent eight infrared sauna sessions over four weeks at temperatures of approximately 55°C for 30 minutes per session. Both patient groups showed clinically meaningful reductions in pain and stiffness during the treatment period, with no adverse effects on disease activity markers (ESR, CRP). Fatigue scores also improved. The authors concluded that infrared sauna is well-tolerated and produces short-term symptomatic benefit in inflammatory arthritis, though they cautioned that larger trials with longer follow-up are needed to establish durability of effects. The study demonstrates that infrared sauna's lower operating temperature allows therapeutic heat exposure in populations that might not tolerate 80-100°C traditional sauna.

Comprehensive Benefits Review (Laukkanen et al., 2018)

This review in Mayo Clinic Proceedings provided a broad assessment of sauna-associated health benefits drawing on the KIHD cohort and other evidence [4]. Beyond cardiovascular mortality, the authors documented associations between frequent Finnish sauna use and reduced risk of sudden cardiac death, coronary heart disease, stroke, hypertension, dementia, and respiratory disease. Proposed mechanisms included improved endothelial and cardiac function, reduced oxidative stress and inflammation, beneficial modulation of the autonomic nervous system, and positive effects on circulating lipid profiles. The review explicitly noted that most outcome data pertains to Finnish-style sauna at 80-100°C, and that while infrared sauna shows promise in smaller studies and specific clinical populations, the long-term outcome data required to make equivalent health claims does not yet exist.

References

Association between sauna bathing and fatal cardiovascular and all-cause mortality eventsLaukkanen T, Khan H, Zaccardi F, Laukkanen JA. JAMA Internal Medicine, 2015. PubMed 25705824 →
Clinical effects of regular dry sauna bathing: a systematic reviewHannuksela ML, Ellahham S. European Journal of Cardiovascular Prevention and Rehabilitation, 2001. PubMed 19104826 →
Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitisOosterveld FG, Rasker JJ, Floors M, Landkroon R, van Rennes B, Zwijnenberg J, van de Laar MA, Koel GJ. Clinical Rheumatology, 2009. PubMed 19666235 →
Cardiovascular and other health benefits of sauna bathing: a review of the evidenceLaukkanen JA, Laukkanen T, Kunutsor SK. Mayo Clinic Proceedings, 2018. PubMed 28602773 →
Sauna use as a lifestyle practice to extend healthspanPatrick RP, Johnson TL. Experimental Gerontology, 2021. PubMed 34363927 →