Sauna & Cold Plunge Research: What the Evidence Says

A Reader's Guide to the Medical Literature

This guide summarizes peer-reviewed research and institutional health guidance on sauna bathing and cold-water immersion. Every statement is drawn from a cited, publicly accessible source. Nothing here is medical advice, and these studies describe associations and physiological responses in research populations — not guarantees that any particular product will produce the same outcomes. Always consult your physician before beginning sauna or cold-exposure protocols, especially if you have cardiovascular risk factors.

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Part I: Sauna Bathing Research

The Finnish Cohort Study (Laukkanen et al., 2015)

The most widely cited study on sauna use and cardiovascular health was published in JAMA Internal Medicine by Dr. Jari A. Laukkanen and colleagues at the University of Eastern Finland. It was a prospective cohort study that followed 2,315 middle-aged men (aged 42–60 at baseline) from eastern Finland over approximately 20 years.

What the study found:

• Men who used the sauna 2–3 times per week had a 23% lower risk of fatal coronary heart disease and fatal cardiovascular disease compared to men who used it once per week.
• Men who used the sauna 4–7 times per week had a 48% lower risk of similar incidents compared to once-weekly users.
• Increased sauna frequency was associated with reduced risk of sudden cardiac death, fatal coronary heart disease, fatal cardiovascular disease, and all-cause mortality.

Important limitations:

• The study was observational, so it shows an association, not proof that sauna use caused the reduced risk. Frequent sauna users may share other healthy lifestyle factors.
• Only men were included; women were not studied.
• The authors noted that further randomized studies are warranted to establish the mechanism connecting sauna bathing with cardiovascular health.
• The population was middle-aged Finnish men in eastern Finland, so results may not generalize to all demographics or sauna traditions.

Source: Laukkanen et al., "Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events," JAMA Internal Medicine (2015). PubMed →

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Editorial: "A Warm Heart Proves Beneficial" (van der Wall, 2015)

In an editorial in the Netherlands Heart Journal, cardiologist Dr. Ernst E. van der Wall reviewed the clinical data on sauna therapy and summarized the safety profile:

"As a rule of thumb, if a person can walk into a sauna, he or she can walk out of it."

He further noted that "sauna baths are well tolerated and pose no risk to healthy people from infancy to old age, including healthy women with uncomplicated pregnancy," and that cardiovascular patients who are stable and relatively asymptomatic "may take sauna baths without undue risk."

The editorial also reviewed a Swedish study showing that death in a sauna is a rare event, with an annual rate of fewer than 2 per 100,000 inhabitants in Finland, and that approximately half of those cases involved alcohol.

Source: van der Wall, "Sauna bathing: a warm heart proves beneficial," Netherlands Heart Journal (2015). Open Access (CC-BY). PMC →

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Systematic Review of Sauna Research (Hussain & Cohen, 2018)

A systematic review published in Evidence-Based Complementary and Alternative Medicine examined 40 clinical studies involving 3,855 participants. Only 13 of the studies were randomized controlled trials, and most were small (fewer than 40 participants each).

The review concluded that "regular dry sauna bathing has potential health benefits" but noted that "more data of higher quality is needed on the frequency and extent of adverse side effects" and called for further study "to determine the optimal frequency and duration of distinct types of sauna bathing for targeted health effects and the specific clinical populations who are most likely to benefit."

The most established clinical benefits were associated with cardiovascular disease outcomes, though the authors noted the evidence base has significant quality limitations.

Source: Hussain & Cohen, "Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review," Evidence-Based Complementary and Alternative Medicine (2018). Open Access (CC-BY). PMC →

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Part II: Cold-Water Immersion Research

Mayo Clinic Health System on Cold Plunging

Mayo Clinic Health System published guidance from sports medicine specialist Andrew Jagim, Ph.D., on the use of cold-water immersion for exercise recovery:

"Research indicates that icy water may have a positive effect on recovery after exercise by reducing inflammation and soreness. It also may help build resiliency, restore balance to the nervous system and improve cognitive function and mood."

On the mechanism: "These benefits may be the result of rapid constriction of the blood vessels due to the cold water. The cold can trigger responses in your body, such as decreased metabolic activity, alterations in hormone production and blood flow, and activation of the immune system."

Important safety guidance from the same source:

• "If you have risk factors associated with cardiovascular disease, such as high blood pressure, check with your primary care provider or cardiologist so you know it's safe for you to cold plunge."
• "For those engaged in resistance training, cold water may turn down the molecular signaling pathways that are normally activated after exercise. This may hinder long-term improvements in strength, muscle growth and performance."
• Water should be 50°F or colder, and plungers typically start with 30 seconds to a minute and work up to 5–10 minutes.

Source: Andrew Jagim, Ph.D., "Can taking a cold plunge after your workout be beneficial?" Mayo Clinic Health System. Read the full article →

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Review: "Health Effects of Voluntary Exposure to Cold Water" (Espeland et al., 2022)

A comprehensive review published in the International Journal of Circumpolar Health surveyed 104 studies on voluntary cold-water immersion. The authors found:

"CWI seems to reduce and/or transform body adipose tissue, as well as reduce insulin resistance and improve insulin sensitivity. This may have a protective effect against cardiovascular, obesity and other metabolic diseases and could have prophylactic health effects."

However, they also cautioned:

"Whether winter swimmers as a group are naturally healthier is unclear."

And concluded:

"Some of the studies indicate that voluntary exposure to cold water has some beneficial health effects. However, without further conclusive studies, the topic will continue to be a subject of debate."

Key limitations noted: "Clear conclusions from most studies were hampered by the fact that they were carried out in small groups, often of one gender and with differences in exposure temperature and salt composition of the water."

The review also documented the cold-shock response, which includes "sympathetically mediated tachycardia, respiratory gasping, uncontrollable hyperventilation, peripheral vasoconstriction and hypertension" — a reminder that cold-water immersion places acute stress on the cardiovascular system and carries real risk for unadapted individuals.

Source: Espeland, de Weerd & Mercer, "Health effects of voluntary exposure to cold water – a continuing subject of debate," International Journal of Circumpolar Health (2022). Open Access (CC-BY-NC). PMC →

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Summary: What the Evidence Supports

| Modality | What Studies Report | Key Limitations | |---|---|---| | Sauna | Association between frequent sauna use and reduced cardiovascular mortality in middle-aged Finnish men; generally well-tolerated by healthy individuals. | Observational data; mostly male subjects; association, not causation; more high-quality RCTs needed. | | Cold Plunge | Possible reduction in exercise-induced muscle soreness and inflammation; potential metabolic effects including improved insulin sensitivity. | Small studies; heterogeneous protocols; cardiovascular stress during immersion; may hinder long-term strength gains; more research needed. |

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Important Disclaimers

• This guide summarizes published research. It is not medical advice.
• These studies describe outcomes in research populations, not guarantees about any specific product. Owning a sauna or cold plunge does not mean you will experience the health outcomes described in these studies.
• Consult your physician before beginning sauna or cold-exposure protocols, especially if you have cardiovascular risk factors, are pregnant, or take medications that affect circulation or blood pressure.
• The FTC requires that health-related marketing claims be supported by competent and reliable scientific evidence. For more information, see the FTC Health Products Compliance Guidance.

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Last reviewed: October 2026. All sources are linked inline and were accessed at the time of writing. This page will be updated as new research becomes available.