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Sauna and Mental Health

About the evidence: The strongest mood-related trial evidence comes from medical whole-body hyperthermia (WBH) devices, not consumer saunas (Janssen et al., 2016) — the two are not interchangeable, and the researchers themselves say the evidence is not yet sufficient for clinical recommendation (Hanusch & Janssen, 2019). What has been measured directly in Finnish saunas is the acute hormonal response — noradrenaline, prolactin, beta-endorphin and cortisol (Kukkonen-Harjula et al., 1989; Leppäluoto et al., 1986). Cohort data on dementia is observational and male-only (Laukkanen et al., 2017). Nothing here is a treatment for a diagnosed mental health condition.

Quick Answer

Sauna use produces measurable neuroendocrine changes that are relevant to mood. A single sauna session has been shown to change circulating noradrenaline, prolactin, beta-endorphin and cortisol — hormones and neurotransmitters involved in arousal, calm and stress regulation (Kukkonen-Harjula et al., 1989; Jezová et al., 1985). What is not established is that this translates into treatment of depression or anxiety. The trial evidence for hyperthermia and depression used clinical whole-body hyperthermia equipment rather than a sauna (Janssen et al., 2016), and no randomised trial has tested consumer sauna bathing for a diagnosed mental health condition. Frequent sauna bathing is separately associated with lower dementia risk in one long-running Finnish cohort of middle-aged men (Laukkanen et al., 2017). For the complete scientific framework, see our Evidence-Based Review of Sauna Therapy.

Sauna and Depression: The Evidence

The relationship between heat and depression has been investigated through the "thermosensory pathway to depression" hypothesis, which proposes that reduced use of warm, social environments in depressed individuals contributes to a feedback loop that worsens mood through impaired thermoregulatory reward signalling (Hanusch et al., 2013). This remains a hypothesis, not a demonstrated cause of depression.

Whole-Body Hyperthermia RCT (Janssen et al., 2016)

A randomised, sham-controlled trial of 34 participants published in JAMA Psychiatry investigated the effect of a single whole-body hyperthermia (WBH) session — which raises core temperature to approximately 38.5 degrees C, comparable to the elevation produced by a sauna session — on major depressive disorder (Janssen et al., 2016). Reported findings:

  • A single WBH session was followed by a reduction in depression scores within 1 week
  • The difference from sham persisted across the 6-week follow-up
  • The reduction on the Hamilton Depression Rating Scale (HDRS-17) was approximately 4.8 points versus sham

Two important qualifications. First, this was a small single-session trial (n=34) using clinical-grade WBH equipment — an infrared heating device under medical supervision — not a sauna. The heating profile, duration and monitoring differ from a domestic or commercial sauna, and no trial has shown the two are equivalent. Second, the same research group's own systematic review of seven WBH studies concluded that the evidence is not yet sufficient to recommend hyperthermia for clinical use in depression (Hanusch & Janssen, 2019). It is reasonable to describe this as an early, promising signal. It is not reasonable to describe sauna as a treatment for depression, and we do not.

Thermosensory Pathway Hypothesis

The research group (Hanusch et al., 2013; Hanusch & Janssen, 2019) has proposed that any antidepressant effect of whole-body hyperthermia works through the thermosensory pathway — warm thermoreceptors in the skin that project to the dorsal raphe nucleus, a key serotonin-producing brain region. Activation of this warm-sensing pathway is proposed to increase serotonergic signalling. This is a mechanistic hypothesis derived largely from preclinical work; it has not been directly measured in humans during sauna bathing, and the suggestion that sauna might add to the antidepressant effect of exercise is untested.

Sauna and Anxiety Reduction

Anxiety disorders represent the most prevalent category of mental health conditions worldwide. Sauna has not been tested in any clinical trial for anxiety disorders, and no anxiety outcome data exists for sauna bathing. What follows is mechanistic reasoning, not evidence of benefit:

Beta-Endorphin Release

Sauna exposure has been shown to raise circulating beta-endorphin and ACTH in healthy adults (Jezová et al., 1985; Vescovi et al., 1992), and beta-endorphin immunoreactivity rose at 100 degrees C in a controlled sauna study of eight healthy men (Kukkonen-Harjula et al., 1989). The findings are not uniform — the same 1989 study did not see the rise at the lower 80 degrees C exposure, so the response appears to depend on how hot and how long the session is. Endorphins are involved in pain modulation and reward signalling, and it is plausible that they contribute to the settled feeling many people report after a sauna. Whether that translates to a reduction in clinical anxiety has not been studied.

Post-Sauna Parasympathetic Dominance

A feature of anxiety disorders is excessive sympathetic nervous system activation. Sauna bathing produces a large acute sympathetic and cardiovascular response — heart rate rose 60–130 percent depending on conditions in controlled testing (Kukkonen-Harjula et al., 1989) — followed by a cool-down period in which heart rate and blood pressure fall back and often below pre-session values (Kukkonen-Harjula & Kauppinen, 2006). This post-session recovery is frequently described as parasympathetic rebound. It is a short-lived physiological state; the idea that repeating it produces lasting anxiety relief is a reasonable hypothesis that has not been tested.

Cortisol

Chronic stress is characterised by dysregulated cortisol. In a controlled study of repeated sauna bathing — one hour twice daily for seven days — serum cortisol and plasma ACTH decreased by the end of the week (Leppäluoto et al., 1986), and acute cortisol also fell during 80 and 100 degrees C exposures in a separate controlled study (Kukkonen-Harjula et al., 1989). Other work has reported cortisol rising acutely (Vescovi et al., 1992), so the direction is not consistent across protocols. A mechanistic review has proposed sauna as a stress-hormone modulator in high-stress occupations, while noting the evidence is mechanistic rather than clinical (Henderson et al., 2021). We have removed previous claims about lower evening cortisol, restored diurnal rhythm and faster cortisol recovery after stressors — no sauna study has measured those outcomes.

Sauna and Stress: The Physiology

Psychological stress produces a well-characterised physiological response: activation of the HPA (hypothalamic-pituitary-adrenal) axis, release of cortisol and adrenaline, increased heart rate and blood pressure, reduced digestive and immune function, and increased inflammatory cytokines. Chronic stress maintains these physiological changes at a low-level, persistent activation that produces cumulative damage across multiple organ systems.

Regular sauna use has been proposed to address stress through several pathways. These are mechanisms and associations, not demonstrated stress-reduction outcomes:

  • Hormetic conditioning: The controlled, predictable heat load of a sauna session has been proposed as a hormetic stressor that may improve how the body handles other stressors (Henderson et al., 2021). This is a proposed mechanism; stress-inoculation from sauna has not been demonstrated in a trial
  • Parasympathetic rebound: The post-sauna recovery period is characterised by falling heart rate and blood pressure (Kukkonen-Harjula & Kauppinen, 2006)
  • Inflammation: In the KIHD cohort of 2,269 middle-aged Finnish men, more frequent sauna bathing was associated with lower high-sensitivity CRP, fibrinogen, leucocyte count and GGT over 11 years (Kunutsor et al., 2018). This is an observational association in men only, and inflammation was measured in blood, not in the brain
  • Social context: Traditional sauna use is a social activity, and social connection is a robust predictor of health outcomes (Holt-Lunstad et al., 2015)

Neurobiological Mechanisms

The neuroendocrine effects of sauna use have been measured in small acute studies (single session) and a small number of short repeated-exposure studies. Almost all of this work is mechanistic — it measures hormones in blood, not mood outcomes.

Summary of Key Neurochemical Effects

Neurochemical Direction (measured in sauna studies) Proposed mental health relevance Source
Noradrenaline (norepinephrine) Increased ~100% at 80 °C and ~160% at 100 °C (n=8 men) Alertness and attention; not measured as a mood outcome Kukkonen-Harjula et al., 1989
Prolactin Increased 2- to 10-fold acutely; 2.3-fold in men over 7 days of repeated bathing Associated with post-stress recovery states; mental health relevance unestablished Kukkonen-Harjula et al., 1989; Leppäluoto et al., 1986
Beta-endorphin Increased in some protocols; not seen at lower temperatures Pain modulation and reward; proposed contributor to post-sauna calm Jezová et al., 1985; Vescovi et al., 1992; Kukkonen-Harjula et al., 1989
Cortisol Inconsistent — decreased acutely and after 7 days in some studies, increased in others Direction of any stress-axis benefit is unresolved Leppäluoto et al., 1986; Kukkonen-Harjula et al., 1989; Vescovi et al., 1992
BDNF Increased after passive heat exposure in young and older adults Neuroplasticity; no sauna-specific BDNF study exists Kirby et al., 2025; Goulet et al., 2023
Dynorphins Not measured in any human sauna study Hypothetical only — see below —
Serotonin Not measured in humans during sauna Proposed thermosensory–raphe mechanism from WBH research Hanusch et al., 2013

Endorphins, Dynorphins and the Post-Sauna Effect

A widely repeated account of the post-sauna "afterglow" holds that heat stress releases dynorphins — the brain's endogenous "anti-reward" molecules — which sensitise mu-opioid receptors so that endorphins released afterwards produce a disproportionately strong sense of wellbeing. We want to be direct about the status of this idea: it is a hypothesis, not a finding. No human sauna study has measured dynorphin, and the receptor-sensitisation sequence has not been demonstrated in people using a sauna. We previously presented this mechanism as established and have corrected that here.

What has been measured is more modest. Beta-endorphin and ACTH rise during sauna exposure in healthy adults in several studies (Jezová et al., 1985; Vescovi et al., 1992), though not at every temperature tested (Kukkonen-Harjula et al., 1989). That is a real, replicated acute hormonal response, and it is a plausible partial explanation for why people feel settled and clear-headed after a sauna. It is not proof of a distinct euphoria mechanism, and it has not been compared head-to-head with exercise.

Norepinephrine and Focus

Norepinephrine (noradrenaline) is a primary alertness and attention neurotransmitter. Sauna exposure raises circulating noradrenaline substantially: in a controlled study of eight healthy men, plasma noradrenaline rose about 100 percent at 80 degrees C, about 160 percent at 100 degrees C, and about 310 percent in hot, humid conditions taken to exhaustion, while adrenaline did not change (Kukkonen-Harjula et al., 1989). This roughly two- to three-fold acute rise is one of the most reliably reproduced hormonal effects of sauna bathing.

Whether it produces the post-sauna mental clarity users describe is not established — no sauna study has measured attention or cognitive performance alongside noradrenaline. Likewise, the suggestion that noradrenaline dampens microglial activation and neuroinflammation comes from preclinical neuroscience, not from sauna research; we previously implied sauna-derived neuroprotection through this route and have removed that claim, as no study has tested it.

Sauna and Brain Health: BDNF and Neuroplasticity

Brain-Derived Neurotrophic Factor (BDNF) supports neuronal survival, synaptic plasticity and learning, and low BDNF is a recurring finding in major depression. Passive heat exposure does appear to raise it: serum BDNF increased from baseline in both young and older adults after nine hours of hot ambient exposure (Kirby et al., 2025), and serum BDNF rose following occupational heat stress across age groups and in men with hypertension or type 2 diabetes (Goulet et al., 2023).

Two caveats matter. Neither study used a sauna — they used prolonged ambient heat and heat-plus-work protocols, which differ from a 15-minute sauna session in intensity and duration. And no study has linked a heat-induced BDNF rise to any change in mood, cognition or depression risk. The claim that sauna builds neuroplasticity or protects against depressive episodes through BDNF is an extrapolation, and we have labelled it as one rather than asserting it.

Separately, frequent sauna bathing was associated with lower dementia and Alzheimer's disease incidence in the KIHD cohort — 66 percent lower dementia risk (HR 0.34) and 65 percent lower Alzheimer's risk (HR 0.35) at 4–7 sessions per week compared with once weekly (Laukkanen et al., 2017). This is a prospective observational study in 2,315 middle-aged Finnish men. It cannot establish that sauna prevents dementia, it does not include women, and it does not tell us the mechanism — the BDNF and heat-shock-protein explanations remain hypotheses. See: Sauna and Longevity: Complete Evidence-Based Guide.

HPA Axis Regulation and Cortisol

The HPA axis (hypothalamic-pituitary-adrenal axis) is the body's primary stress response system. Chronic HPA dysregulation — either hyper-reactivity or a blunted cortisol response — is associated with depression, anxiety disorders, PTSD and burnout.

Sauna bathing clearly engages this axis: ACTH rises acutely during hotter exposures (Kukkonen-Harjula et al., 1989; Jezová et al., 1985), and after seven days of twice-daily bathing both ACTH and cortisol were lower than at baseline (Leppäluoto et al., 1986). That week-long study is the closest thing we have to evidence of HPA adaptation, and it is a single small study in 17 volunteers over seven days.

The broader idea — that repeated sauna sessions train the HPA axis to respond less excessively to psychological stressors and recover faster — is a proposed hormetic mechanism (Henderson et al., 2021) rather than a demonstrated outcome. No trial has measured stress reactivity or resilience in regular sauna users. We have kept the mechanism because it is coherent and consistent with the hormonal data, but it should be read as a hypothesis, not as a benefit you can count on.

The Social Dimension of Sauna and Mental Health

In Finnish culture, the sauna is a fundamentally social institution. Traditional sauna bathing is done communally — families, friends, colleagues and communities share the sauna experience. Any mental health benefit is therefore hard to separate from the psychological and social benefits of shared ritual and connection.

Social connection is a well-established predictor of health outcomes. A meta-analytic review found social isolation associated with a 29 percent increase in mortality risk, loneliness 26 percent, and living alone 32 percent (Holt-Lunstad et al., 2015). Whether the sauna specifically delivers mental health benefit through this social channel has not been studied — no research has separated the social component of sauna bathing from the thermal one. We flag it because it is a plausible and often-overlooked confounder in the observational Finnish data, where sauna use, social participation and lifestyle are entangled.

For solo sauna users, the ritual element — deliberately setting aside time for a contemplative, screen-free experience — may carry mindfulness-like benefits. That is an observation about the practice, not a research finding.

Mental Health Protocols

These protocols reflect the exposures used in the general sauna literature and common practice. They have not been validated for any mental health outcome — no trial has tested a sauna protocol for depression, anxiety or stress. Treat them as a sensible starting point for general wellbeing, not as a clinical intervention.

Protocol 1: General Wellbeing and Relaxation

Parameter Specification
Frequency 3-5 sessions per week
Temperature 80-95 degrees C (the range in which the noradrenaline and endorphin responses have been measured)
Duration 15-20 minutes per round, 1-2 rounds
Timing Late afternoon or evening
Context Social when possible; if solo, treat as mindfulness practice — no screens

Protocol 2: Using Sauna Alongside Mental Health Care

Parameter Specification
Frequency 3-5 sessions per week, as tolerated
Temperature 80-100 degrees C
Duration 15 minutes minimum per session
Important note Sauna is not a treatment for depression or anxiety and is not a substitute for professional mental health care or prescribed medication. Talk to your doctor before adding heat exposure if you are taking psychiatric medication — some medications affect thermoregulation, blood pressure and hydration

Evidence Summary Table

Outcome Key Evidence Effect Study type
Major depression (whole-body hyperthermia, not sauna) Janssen et al., 2016, JAMA Psychiatry HDRS-17 reduction ~4.8 points vs sham, sustained to 6 weeks after a single session Sham-controlled RCT, n=34 (small)
Depression — clinical readiness Hanusch & Janssen, 2019 Authors conclude evidence across 7 WBH studies is not yet sufficient to recommend clinical use Systematic review, 148 subjects
Anxiety disorders No studies No trial evidence exists for sauna and anxiety —
Noradrenaline Kukkonen-Harjula et al., 1989 ~100% rise at 80 °C, ~160% at 100 °C; adrenaline unchanged Controlled physiological study, n=8 men
Beta-endorphin / ACTH Jezová et al., 1985; Vescovi et al., 1992 Acute rise in healthy adults; not observed at all temperatures Small controlled physiological studies
Cortisol / HPA axis Leppäluoto et al., 1986 ACTH and cortisol lower after 7 days of twice-daily bathing; other studies show acute rises Repeated-exposure study, n=17
BDNF Kirby et al., 2025; Goulet et al., 2023 Serum BDNF rises after passive/occupational heat exposure — not sauna, and not linked to mood outcomes Heat-exposure studies (secondary analysis)
Inflammation Kunutsor et al., 2018 (KIHD) Frequent sauna associated with lower hsCRP, fibrinogen, leucocytes, GGT over 11 years Prospective cohort, 2,269 men (observational)
Dementia / Alzheimer's Laukkanen et al., 2017 (KIHD) 66% lower dementia (HR 0.34) and 65% lower AD (HR 0.35) at 4-7×/week vs 1×/week Prospective cohort, 2,315 men (observational, male-only)

Frequently Asked Questions

Can sauna help with depression?

There is no trial evidence that sauna bathing treats depression, and it should not be used as a treatment. The often-cited trial result comes from a different intervention: a sham-controlled trial of medical whole-body hyperthermia equipment, which found a reduction in depression scores sustained over six weeks after a single session in 34 participants (Janssen et al., 2016). The same researchers later concluded the overall evidence is not yet sufficient for clinical recommendation (Hanusch & Janssen, 2019). Sauna does produce hormonal changes relevant to mood regulation, but no one has shown those changes improve depression. If you are managing depression, sauna may be a pleasant addition to your routine — it is not a substitute for professional care.

How does sauna reduce stress?

Honestly, the direct evidence is thinner than it is often made out to be. What is measured: sauna produces a large acute cardiovascular and noradrenaline response followed by a recovery period in which heart rate and blood pressure fall (Kukkonen-Harjula et al., 1989; Kukkonen-Harjula & Kauppinen, 2006), and after a week of repeated bathing, cortisol and ACTH were lower than baseline in one small study (Leppäluoto et al., 1986). The hormetic idea — that repeated controlled heat stress trains the stress axis — is a proposed mechanism (Henderson et al., 2021), not a tested outcome. No study has measured perceived stress in sauna users.

Does sauna make you feel happier?

Many people report a distinct post-sauna calm, and there is a real hormonal response underneath it — beta-endorphin, ACTH, prolactin and noradrenaline all shift measurably during and after a session (Kukkonen-Harjula et al., 1989; Jezová et al., 1985; Leppäluoto et al., 1986). What we cannot honestly tell you is that these changes cause the feeling: no sauna study has measured mood alongside hormones. The popular dynorphin "afterglow" explanation has never been tested in humans using a sauna.

Can sauna help with anxiety?

Sauna has never been tested in a clinical trial for anxiety, so there is no evidence-based answer. The mechanistic reasoning — endorphin release, post-session parasympathetic recovery — is plausible but unproven for anxiety outcomes. If you find a sauna session calming, that experience is worth something on its own terms; it just isn't a clinical result.

How often should I use a sauna for mental health benefits?

No frequency has been validated for mental health outcomes, because those trials have not been done. The Finnish cohort data associating frequent bathing with lower dementia risk used 4–7 sessions per week in middle-aged men (Laukkanen et al., 2017), and 3–5 sessions per week is a common, well-tolerated pattern in the general sauna literature (Kukkonen-Harjula & Kauppinen, 2006). Use that as a practical range rather than a prescription.

References

  • Janssen CW, Lowry CA, Mehl MR, Allen JJ, Kelly KL, Gartner DE, et al. (2016). Whole-Body Hyperthermia for the Treatment of Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry. PMID: 27172277
  • Hanusch KU, Janssen CW. (2019). The impact of whole-body hyperthermia interventions on mood and depression — are we ready for recommendations for clinical application? International Journal of Hyperthermia. PMID: 31159624
  • Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen JA. (2017). Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men. Age and Ageing. PMID: 27932366
  • Kunutsor SK, Laukkanen T, Laukkanen JA. (2018). Longitudinal associations of sauna bathing with inflammation and oxidative stress: the KIHD prospective cohort study. Annals of Medicine. PMID: 29897261
  • Holt-Lunstad J, Smith TB, Baker M, Harris T, Stephenson D. (2015). Loneliness and social isolation as risk factors for mortality: a meta-analytic review. Perspectives on Psychological Science. PMID: 25910392
  • Kukkonen-Harjula K, Oja P, Laustiola K, Vuori I, Jolkkonen J, Siitonen S, et al. (1989). Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath. European Journal of Applied Physiology and Occupational Physiology. PMID: 2759081
  • Leppäluoto J, Huttunen P, Hirvonen J, Väänänen A, Tuominen M, Vuori J. (1986). Endocrine effects of repeated sauna bathing. Acta Physiologica Scandinavica. PMID: 3788622
  • Hanusch KU, Janssen CH, Billheimer D, Jenkins I, Spurgeon E, Lowry CA, et al. (2013). Whole-body hyperthermia for the treatment of major depression: associations with thermoregulatory cooling. American Journal of Psychiatry. PMID: 23820835
  • Kirby N, Meade R, McCormick J, King K, Kenny GP. (2025). Brain-derived neurotrophic factor response to daylong exposure to extreme heat in young and older adults: a secondary analysis. Applied Physiology, Nutrition, and Metabolism. PMID: 39970395
  • Goulet N, McCormick JJ, King KE, Notley SR, Goldfield GS, Fujii N, et al. (2023). Elevations in serum brain-derived neurotrophic factor following occupational heat stress are not influenced by age or common chronic disease. Temperature. PMID: 38130657
  • Vescovi PP, Coiro V, Volpi R, Giannini A, Passeri M. (1992). Hyperthermia in sauna is unable to increase the plasma levels of ACTH/cortisol, beta-endorphin and prolactin in cocaine addicts. Journal of Endocrinological Investigation. PMID: 1336021
  • Jezová D, Vigas M, Tatár P, Jurcovicová J, Palát M. (1985). Rise in plasma beta-endorphin and ACTH in response to hyperthermia in sauna. Hormone and Metabolic Research. PMID: 3002937
  • Henderson KN, Killen LG, O'Neal EK, Waldman HS. (2021). The Cardiometabolic Health Benefits of Sauna Exposure in Individuals with High-Stress Occupations: A Mechanistic Review. International Journal of Environmental Research and Public Health. PMID: 33513711
  • Kukkonen-Harjula K, Kauppinen K. (2006). Health effects and risks of sauna bathing. International Journal of Circumpolar Health. PMID: 16871826
  • Laukkanen JA, Laukkanen T, Kunutsor SK. (2018). Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence. Mayo Clinic Proceedings. PMID: 30077204

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