The Human Operating Manual

The HOM letters intertwined to form a human
Menu

Thermoregulation Resources

Foundational Researchers in Thermal Physiology

Vienna Brunt. University of Colorado Boulder. Passive heat therapy and endothelial function. The 2016 Journal of Physiology work documenting improvements in flow-mediated dilation, arterial stiffness, and blood pressure after 8 weeks of passive heat exposure.

  • Brunt, V.E., Howard, M.J., Francisco, M.A., Ely, B.R., & Minson, C.T. (2016). Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. The Journal of Physiology, 594(18), 5329–5342.

Aaron Cypess. National Institutes of Health. Adult human brown adipose tissue research. The 2009 NEJM paper that helped establish that adults retain functional BAT.

  • Cypess, A.M., Lehman, S., Williams, G., Tal, I., Rodman, D., Goldfine, A.B., Kuo, F.C., Palmer, E.L., Tseng, Y.H., Doria, A., Kolodny, G.M., & Kahn, C.R. (2009). Identification and importance of brown adipose tissue in adult humans. New England Journal of Medicine, 360(15), 1509–1517.

Craig Heller and Dennis Grahn. Stanford University. The palm cooling research with substantive performance implications. The arteriovenous anastomoses mechanism. Applied to athletic performance, medical rewarming, and animal applications.

  • Heller, H.C., & Grahn, D.A. (2012). Enhancing thermal exchange in humans and practical applications. Disruptive Science and Technology, 1(1), 11–19.

Mark Iguchi. Research on heat stress and heat shock protein expression. The 2012 work documenting HSP70 elevation patterns with sauna exposure.

Key works:

  • Iguchi, M., Littmann, A.E., Chang, S.H., Wester, L.A., Knipper, J.S., & Shields, R.K. (2012). Heat stress and cardiovascular, hormonal, and heat shock proteins in humans. Journal of Athletic Training, 47(2), 184–190.

Bruce McEwen (1938-2020). Rockefeller University. The allostatic load framework. Cross-referenced from The Emotion Rabbit Hole. Relevant to understanding thermal exposure as a stressor that can support or deplete the broader stress architecture depending on dose and recovery.

  • McEwen, B.S. (1998). Stress, adaptation, and disease: Allostasis and allostatic load. Annals of the New York Academy of Sciences, 840(1), 33–44.

Donald Meichenbaum. University of Waterloo. Stress inoculation framework. Cross-referenced from The Emotion Rabbit Hole. The framework that thermal exposure operationalises directly.

  • Meichenbaum, D. (1985). Stress inoculation training. Pergamon Press.

Kazuhiro Nakamura. Nagoya University. Central circuitry for body temperature regulation. The 2011 work mapping the neural pathways from hypothalamus to thermoregulatory effectors in detail.

  • Nakamura, K. (2011). Central circuitries for body temperature regulation and fever. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 301(5), R1207–R1228.

Hideo Naito. Research on heat stress and muscle preservation. The 2000 paper documenting heat-mediated attenuation of muscle atrophy during disuse.

  • Naito, H., Powers, S.K., Demirel, H.A., Sugiura, T., Dodd, S.L., & Aoki, J. (2000). Heat stress attenuates skeletal muscle atrophy in hindlimb-unweighted rats. Journal of Applied Physiology, 88(1), 359–363.

Diana Peretti. University of Leicester. RBM3 cold shock protein and neurodegeneration research. The 2015 Nature paper documenting protective effects of cooling-induced RBM3 expression in neurodegeneration models.

  • Peretti, D., Bastide, A., Radford, H., Verity, N., Molloy, C., Martin, M.G., Moreno, J.A., Steinert, J.R., Smith, T., Dinsdale, D., Willis, A.E., & Mallucci, G.R. (2015). RBM3 mediates structural plasticity and protective effects of cooling in neurodegeneration. Nature, 518(7538), 236–239.

Hans Selye (1907-1982). University of Montreal. Foundational stress response research. The General Adaptation Syndrome framework that established stress as a biological category. Cross-referenced from The Emotion Rabbit Hole. The conceptual foundation for understanding thermal exposure as hormetic stressor.

  • Selye, H. (1956). The stress of life. McGraw-Hill.

Wouter van Marken Lichtenbelt. Maastricht University. Brown adipose tissue research in humans. The 2009 NEJM paper that helped establish adult human BAT functionality. Substantive ongoing research program on cold exposure and metabolic adaptation.

  • van Marken Lichtenbelt, W.D., Vanhommerig, J.W., Smulders, N.M., Drossaerts, J.M., Kemerink, G.J., Bouvy, N.D., Schrauwen, P., & Teule, G.J. (2009). Cold-activated brown adipose tissue in healthy men. New England Journal of Medicine, 360(15), 1500–1508.

 

Foundational Researchers in Sauna and Heat Exposure Outcomes

Joseph Hussain and Marc Cohen. RMIT University. The 2018 systematic review of sauna bathing clinical effects.

  • Hussain, J., & Cohen, M. (2018). Clinical effects of regular dry sauna bathing: A systematic review. Evidence-Based Complementary and Alternative Medicine, 2018, 1857413.

Charles Janssen, Christopher Lowry, and Charles Raison. University of Wisconsin, University of Colorado Boulder, University of Wisconsin-Madison. The whole-body hyperthermia and depression research. The 2016 JAMA Psychiatry paper documenting substantial reductions in depression symptoms after single hyperthermia sessions.

  • Janssen, C.W., Lowry, C.A., Mehl, M.R., Allen, J.J., Kelly, K.L., Gartner, D.E., Medrano, A., Begay, T.K., Rentscher, K., White, J.J., Fridman, A., Roberts, L.J., Robbins, M.L., Hanusch, K.U., Cole, S.P., & Raison, C.L. (2016). Whole-body hyperthermia for the treatment of major depressive disorder: A randomized clinical trial. JAMA Psychiatry, 73(8), 789–795.

Setor Kunutsor. University of Bristol. Sauna bathing and respiratory disease research. The 2017 paper documenting pneumonia risk reduction in frequent sauna users.

  • Kunutsor, S.K., Laukkanen, T., & Laukkanen, J.A. (2017). Sauna bathing reduces the risk of respiratory diseases: A long-term prospective cohort study. European Journal of Epidemiology, 32(12), 1107–1111.

Tanjaniina Laukkanen. University of Eastern Finland. Co-author on much of the Finnish sauna research with Jari Laukkanen and the KIHD study group.

Jari Laukkanen. University of Eastern Finland. The foundational researcher on sauna bathing and cardiovascular outcomes. The KIHD cohort work spanning decades. The 2015 JAMA Internal Medicine paper. The 2017 dementia and Alzheimer’s research. The 2018 Mayo Clinic Proceedings review. The most consequential research on thermal exposure and health outcomes.

  • Laukkanen, T., Khan, H., Zaccardi, F., & Laukkanen, J.A. (2015). Association between sauna bathing and fatal cardiovascular events and all-cause mortality. JAMA Internal Medicine, 175(4), 542–548.
  • Laukkanen, T., Kunutsor, S., Kauhanen, J., & Laukkanen, J.A. (2017). Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men. Age and Ageing, 46(2), 245–249.
  • Laukkanen, J.A., Laukkanen, T., & Kunutsor, S.K. (2018). Cardiovascular and other health benefits of sauna bathing: A review of the evidence. Mayo Clinic Proceedings, 93(8), 1111–1121.

Setsuko Lorenzo. University of Oregon. Heat acclimation research with applications to athletic performance. The 2010 paper documenting performance improvements in normothermic conditions from heat acclimation training.

  • Lorenzo, S., Halliwill, J.R., Sawka, M.N., & Minson, C.T. (2010). Heat acclimation improves exercise performance. Journal of Applied Physiology, 109(4), 1140–1147.

Chuwa Tei. Kagoshima University. Waon therapy developer. The specific far-infrared sauna protocol for heart failure patients. The 2016 Circulation Journal multicenter trial.

  • Tei, C., Imamura, T., Kinugawa, K., Inoue, T., Masuyama, T., Inoue, H., Noike, H., Muramatsu, T., Takeishi, Y., Saku, K., Harada, K., Daida, H., Kobayashi, Y., Hagiwara, N., Nishigaki, K., Shimizu, A., Yoshida, J., Ikeda, T., Kato, K., … & Hori, M. (2016). Waon therapy for managing chronic heart failure: Results from a multicenter prospective randomized WAON-CHF study. Circulation Journal, 80(4), 827–834.

 

Foundational Researchers in Cold Exposure and BAT

Geert Buijze. University of Amsterdam. The cold shower trial. The 2016 PLOS One paper with 3018 participants documenting 29% reduction in sick day absenteeism with daily cold showers.

  • Buijze, G.A., Sierevelt, I.N., van der Heijden, B.C., Dijkgraaf, M.G., & Frings-Dresen, M.H. (2016). The effect of cold showering on health and work: A randomized controlled trial. PLOS One, 11(9), e0161749.

Marc Hanssen. Maastricht University. Cold acclimation and insulin sensitivity research. The 2015 Nature Medicine paper documenting substantial insulin sensitivity improvements in type 2 diabetics after 10 days of cold acclimation.

  • Hanssen, M.J., Hoeks, J., Brans, B., van der Lans, A.A., Schaart, G., van den Driessche, J.J., Jörgensen, J.A., Boekschoten, M.V., Hesselink, M.K., Havekes, B., Kersten, S., Mottaghy, F.M., van Marken Lichtenbelt, W.D., & Schrauwen, P. (2015). Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus. Nature Medicine, 21(8), 863–865.

Wim Hof. Popular cold exposure practitioner and method developer. Not a researcher himself but the subject of research and the popular face of cold exposure practice. The cultural influence has been substantial.

Honest framing on Hof’s contribution: the systematic codification of cold exposure plus breath work into accessible practice has been valuable. The specific claims about the method’s unique effects sometimes exceed what the underlying research supports (the practices work through pathways that other approaches also engage). The Kox 2014, Buijze 2016, and Muzik 2018 papers anchor what the research establishes. The cultural patterns around WHM (charismatic founder, training certification, branded protocols) have grown beyond the strict research support. The safety concerns around hyperventilation combined with water immersion warrant repeated attention.

  • Hof, W. (2020). The Wim Hof method: Activate your potential, transcend your limits. Sounds True.

Matthijs Kox. Radboud University Medical Center. The 2014 PNAS paper documenting WHM training effects on inflammation in response to endotoxin challenge.

  • Kox, M., van Eijk, L.T., Zwaag, J., van den Wildenberg, J., Sweep, F.C., van der Hoeven, J.G., & Pickkers, P. (2014). Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proceedings of the National Academy of Sciences, 111(20), 7379–7384.

Giovanni Lombardi. University of Milan. The 2017 review of whole-body cryotherapy in athletes. The substantive synthesis of cryotherapy chamber research with appropriate calibration on evidence quality.

  • Lombardi, G., Ziemann, E., & Banfi, G. (2017). Whole-body cryotherapy in athletes: From therapy to stimulation. An updated review of the literature. Frontiers in Physiology, 8, 258.

Otto Muzik. Wayne State University. The “Brain over Body” study of Wim Hof. The 2018 Neuroimage paper documenting unusual neural and autonomic patterns during cold exposure.

  • Muzik, O., Reilly, K.T., & Diwadkar, V.A. (2018). “Brain over body”: A study on the willful regulation of autonomic function during cold exposure. NeuroImage, 172, 632–641.

Aaron Petersen. University of Melbourne. The 2021 meta-analysis on post-exercise cold water immersion effects on resistance training adaptations. The substantive synthesis of the Roberts 2015 findings and subsequent research.

  • Petersen, A.C., & Fyfe, J.J. (2021). Post-exercise cold water immersion effects on physiological adaptations to resistance training and the underlying mechanisms in skeletal muscle: A narrative review. Frontiers in Sports and Active Living, 3, 660291.

Llion Roberts. University of Queensland. The foundational 2015 Journal of Physiology paper on cold immersion blunting strength training adaptations. The work that established the strength training timing caveat that’s still commonly missed in popular practice.

  • Roberts, L.A., Raastad, T., Markworth, J.F., Figueiredo, V.C., Egner, I.M., Shield, A., Cameron-Smith, D., Coombes, J.S., & Peake, J.M. (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. The Journal of Physiology, 593(18), 4285–4301.

Susanna Søberg. University of Copenhagen. The foundational researcher on cold thermogenesis and brown adipose tissue adaptation in humans. The 2021 Cell Reports Medicine paper on winter swimmers. The Søberg Principle that emerged from her work and subsequent research.

  • Søberg, S., Löfgren, J., Philipsen, F.E., Jensen, M., Hansen, A.E., Ahrens, E., Nystrup, K.B., Nielsen, R.D., Sølling, C., Wedell-Neergaard, A.S., Berntsen, M., Loft, A., Kjær, A., Gerhart-Hines, Z., Johannesen, H.H., Pedersen, B.K., Karstoft, K., & Scheele, C. (2021). Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine, 2(10), 100408.

Lukáš Šrámek. Charles University in Prague. The 2000 paper documenting neurochemical responses to cold water immersion. The specific dopamine and norepinephrine elevation patterns (approximately 250% dopamine, 530% norepinephrine increases) that anchor the mood and alertness effects of cold exposure.

  • Šrámek, P., Šimečková, M., Janský, L., Šavlíková, J., & Vybíral, S. (2000). Human physiological responses to immersion into water of different temperatures. European Journal of Applied Physiology, 81(5), 436–442.

 

Foundational Researchers in Performance and Applied Thermal Physiology

Andrew Huberman: Stanford University. Substantive synthesis of thermal exposure research alongside broader neuroscience content. The Huberman Lab podcast episodes on heat and cold exposure provide accessible synthesis of the research. The Balban et al. 2023 Cell Reports Medicine physiological sigh research is directly relevant to the broader autonomic regulation framework that thermal exposure operates within.

  • The Huberman Lab podcast episodes on sauna, cold exposure, and thermoregulation (available at hubermanlab.com and through podcast platforms)
  • Balban, M.Y., Neri, E., Kogon, M.M., Weed, L., Nouriani, B., Jo, B., Holl, G., Zeitzer, J.M., Spiegel, D., & Huberman, A.D. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 4(1), 100895.

 

Rhonda Patrick: FoundMyFitness. PhD in biomedical science. Substantial accessible synthesis of nutrition, longevity, and thermal exposure research. The FoundMyFitness topic pages on sauna, cold exposure, and whole-body hyperthermia provide useful synthesis with primary literature citations.

 

Cross-Section Foundational Figures

  • Donald Meichenbaum: Stress inoculation framework. Cross-referenced extensively in The Emotion Rabbit Hole. The framework that thermal exposure operationalises directly through deliberate exposure to manageable thermal stressors.
  • Bruce McEwen and Hans Selye: Stress neuroscience and allostatic load. Cross-referenced from The Emotion Rabbit Hole. Foundational to understanding thermal exposure as hormetic stressor.
  • Bessel van der Kolk: Trauma research. Cross-referenced from Emotion Resources. The somatic dimensions of trauma processing connect to thermal exposure as adjunctive practice for some trauma work, with appropriate clinical guidance.
  • Peter Levine: Somatic Experiencing. Cross-referenced from Emotion Resources. The window of tolerance framework that thermal exposure practice can support when used appropriately.
  • Marsha Linehan: DBT and the TIPP skills. Cross-referenced from Emotion Resources. The cold water application in TIPP draws on the mammalian dive reflex covered in detail in Cold Exposure.
  • Robert Sapolsky: Stress neuroscience. Cross-referenced from Emotion Resources. The cortisol architecture that thermal exposure interacts with.
  • Matthew Walker: Sleep research. Cross-referenced from sleep section. The thermal dimensions of sleep architecture and the pre-sleep cooling phenomenon that warm baths and saunas can support.
  • Karl Friston: Active inference framework. Cross-referenced from Emotion Resources. The broader theoretical framework for understanding how the brain processes thermal sensory input as part of overall body state prediction.

 

Books Worth Reading

Organised by category with calibrated framing.

Foundational and Accessible Synthesis Works

  • Susanna Søberg — Winter Swimming: The Nordic Way Toward a Healthier and Happier Life (2022, English translation): The accessible synthesis of Søberg’s research and practical guidance for cold water exposure practice. One of the more research-grounded popular books on thermal exposure. Substantively recommended for serious engagement with cold exposure practice.
  • Andrew Huberman Lab podcast — episodes on thermal exposure: Not a book but functions as one of the more accessible introductions to thermal exposure research. The episodes on sauna, cold exposure, and whole-body hyperthermia cover the primary research with appropriate calibration on evidence quality.
  • Rhonda Patrick FoundMyFitness — topic pages and podcast episodes: Substantive accessible synthesis of the sauna and cold exposure research. The aggregator format provides useful entry points into the primary literature.

 

Practical Synthesis Works with Calibrated Framing

  • Olli Sovijärvi, Teemu Arina, and Jaakko Halmetoja — Biohacker’s Handbook (2017, English translation 2018): Finnish-origin practical synthesis covering thermal exposure alongside broader optimisation topics. Substantive practical guidance grounded partly in the Finnish thermal exposure culture. Mixed evidence base across topics; the thermal exposure sections are reasonably well-anchored. The broader biohacker framing has accumulated substantial commercial and cultural baggage; engaging with the practical content while calibrating against the broader claims is the reasonable approach.
  • Ben Greenfield — Boundless: Upgrade Your Brain, Optimize Your Body, & Defy Aging (2020): Substantial work covering thermal exposure within a broader optimisation framework. Useful as practical reference. The evidence quality varies across topics; thermal exposure coverage is reasonably anchored. Greenfield’s broader work has accumulated substantial commercial integration that warrants calibration. The book functions better as a practical reference than as a primary research source.
  • Tim Ferriss — The Four Hour Body (2010): Practical experimentation framing covering thermal exposure alongside broader self-experimentation. Ferriss’s contribution: making thermal exposure accessible to lay practitioners through readable practical guidance. The evidence quality varies; some claims have aged better than others. The accessible writing has introduced many practitioners to thermal exposure practice.
  • Michael Easter — The Comfort Crisis: Embrace Discomfort to Reclaim Your Wild, Happy, Healthy Self (2021): Accessible synthesis on hormesis broadly, including thermal exposure. The framing emphasises the cultural shift from environments providing natural thermal variation to climate-controlled comfort that has eliminated foundational physiological stressors. Useful conceptual framework; the specific practical guidance is sometimes less rigorous than the conceptual framing. Worth reading for the broader context.
  • Dave Asprey — Super Human: The Bulletproof Plan to Age Backward and Maybe Even Live Forever (2019): Bulletproof founder’s anti-aging synthesis covering thermal exposure within a broader optimisation framework. Substantial claims often exceed what the controlled research supports. The thermal exposure content is partly grounded; the broader anti-aging framing involves substantial overpromise. Useful for the specific practical protocols; substantial calibration warranted on broader claims. Asprey’s commercial integration (Bulletproof products) introduces specific bias considerations.

 

Popular Wellness Works with Substantial Calibration

  • Wim Hof — The Wim Hof Method: Activate Your Potential, Transcend Your Limits (2020): The popular synthesis of Hof’s method by Hof himself. The systematic codification of cold exposure plus breath work is the substantive contribution. The specific claims about the method’s unique effects and the broader cultural framing warrant calibration: the practices work through pathways that other approaches also engage; the method works for many practitioners but isn’t categorically different from other cold exposure or breath work practices. The safety considerations around hyperventilation plus water immersion warrant repeated attention; the book covers this but the popular adoption has sometimes not communicated it adequately.
  • Scott Carney — What Doesn’t Kill Us: How Freezing Water, Extreme Altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary Strength (2017): Journalist’s first-person investigation of cold exposure including extensive coverage of Wim Hof. The journalist’s framing provides useful outside perspective. The specific claims about evolutionary fitness recovery are often overdrawn relative to the empirical evidence; the practical exposure content is more grounded. Worth reading for the cultural and historical context.
  • Kelly Starrett — Built to Move (2023): Movement specialist’s broader practice synthesis including some thermal exposure content. The movement primary focus is the strength; the thermal exposure coverage is supplementary. Worth reading for the broader physical practice framework that thermal exposure fits within.

 

Cultural and Historical Context

  • Lassi Liikkanen — The Sauna: From the Origins to the Present (2019): History of Finnish sauna culture and broader thermal bathing traditions. Useful context for understanding the cultural integration that makes the Finnish epidemiological work possible.
  • Mikkel Aaland — Sweat: The Illustrated History and Description of the Finnish Sauna, Russian Bania, Islamic Hammam, Japanese Mushi-Buro, Mexican Temescal, and American Indian and Eskimo Sweat Lodge (1978): Comprehensive cross-cultural survey of thermal bathing traditions. Substantial historical and anthropological coverage. Older work but the cultural patterns documented remain relevant.
  • Maria Helleberg — Bathing in the Nordic Way (various editions): Scandinavian winter swimming and broader cold water immersion cultural context. The Danish winter swimming tradition that the Søberg research draws on.
  • Clinical Applications
  • Charles Raison and colleagues — academic papers on whole-body hyperthermia for depression: Not a book but a substantive research program with practical clinical applications worth tracking. The Janssen 2016 JAMA Psychiatry paper is the foundational publication.
  • Chuwa Tei and colleagues — academic papers on Waon therapy: Not a book but the substantive Japanese research program on far-infrared sauna for heart failure applications. The 2016 Circulation Journal paper is the foundational publication.

 

Primary Research Worth Citing

  • Balban, M.Y., Neri, E., Kogon, M.M., Weed, L., Nouriani, B., Jo, B., Holl, G., Zeitzer, J.M., Spiegel, D., & Huberman, A.D. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 4(1), 100895.
  • Brunt, V.E., Howard, M.J., Francisco, M.A., Ely, B.R., & Minson, C.T. (2016). Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. The Journal of Physiology, 594(18), 5329–5342.
  • Buijze, G.A., Sierevelt, I.N., van der Heijden, B.C., Dijkgraaf, M.G., & Frings-Dresen, M.H. (2016). The effect of cold showering on health and work: A randomized controlled trial. PLOS One, 11(9), e0161749.
  • Cypess, A.M., Lehman, S., Williams, G., Tal, I., Rodman, D., Goldfine, A.B., Kuo, F.C., Palmer, E.L., Tseng, Y.H., Doria, A., Kolodny, G.M., & Kahn, C.R. (2009). Identification and importance of brown adipose tissue in adult humans. New England Journal of Medicine, 360(15), 1509–1517.
  • Hanssen, M.J., Hoeks, J., Brans, B., et al. (2015). Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus. Nature Medicine, 21(8), 863–865.
  • Hussain, J., & Cohen, M. (2018). Clinical effects of regular dry sauna bathing: A systematic review. Evidence-Based Complementary and Alternative Medicine, 2018, 1857413.
  • Janssen, C.W., Lowry, C.A., Mehl, M.R., et al. (2016). Whole-body hyperthermia for the treatment of major depressive disorder: A randomized clinical trial. JAMA Psychiatry, 73(8), 789–795.
  • Kox, M., van Eijk, L.T., Zwaag, J., et al. (2014). Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proceedings of the National Academy of Sciences, 111(20), 7379–7384.
  • Kunutsor, S.K., Laukkanen, T., & Laukkanen, J.A. (2017). Sauna bathing reduces the risk of respiratory diseases. European Journal of Epidemiology, 32(12), 1107–1111.
  • Laukkanen, T., Khan, H., Zaccardi, F., & Laukkanen, J.A. (2015). Association between sauna bathing and fatal cardiovascular events and all-cause mortality. JAMA Internal Medicine, 175(4), 542–548.
  • Laukkanen, T., Kunutsor, S., Kauhanen, J., & Laukkanen, J.A. (2017). Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men. Age and Ageing, 46(2), 245–249.
  • Laukkanen, J.A., Laukkanen, T., & Kunutsor, S.K. (2018). Cardiovascular and other health benefits of sauna bathing: A review of the evidence. Mayo Clinic Proceedings, 93(8), 1111–1121.
  • Lorenzo, S., Halliwill, J.R., Sawka, M.N., & Minson, C.T. (2010). Heat acclimation improves exercise performance. Journal of Applied Physiology, 109(4), 1140–1147.
  • Muzik, O., Reilly, K.T., & Diwadkar, V.A. (2018). “Brain over body”: A study on the willful regulation of autonomic function during cold exposure. NeuroImage, 172, 632–641.
  • Naito, H., Powers, S.K., Demirel, H.A., et al. (2000). Heat stress attenuates skeletal muscle atrophy in hindlimb-unweighted rats. Journal of Applied Physiology, 88(1), 359–363.
  • Peretti, D., Bastide, A., Radford, H., et al. (2015). RBM3 mediates structural plasticity and protective effects of cooling in neurodegeneration. Nature, 518(7538), 236–239.
  • Roberts, L.A., Raastad, T., Markworth, J.F., et al. (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. The Journal of Physiology, 593(18), 4285–4301.
  • Søberg, S., Löfgren, J., Philipsen, F.E., et al. (2021). Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine, 2(10), 100408.
  • Šrámek, P., Šimečková, M., Janský, L., Šavlíková, J., & Vybíral, S. (2000). Human physiological responses to immersion into water of different temperatures. European Journal of Applied Physiology, 81(5), 436–442.
  • Tei, C., Imamura, T., Kinugawa, K., et al. (2016). Waon therapy for managing chronic heart failure: Results from a multicenter prospective randomized WAON-CHF study. Circulation Journal, 80(4), 827–834.
  • van Marken Lichtenbelt, W.D., Vanhommerig, J.W., Smulders, N.M., et al. (2009). Cold-activated brown adipose tissue in healthy men. New England Journal of Medicine, 360(15), 1500–1508.
  • Wang, B., Sun, S., Liu, M., et al. (2024). Cold exposure, gut microbiota and health implications: A narrative review. Science of the Total Environment, 916, 170060.

 

Practitioner Resources and Facilities

Cultural Bathhouses and Thermal Exposure Traditions

  • Finnish saunas worldwide: Public Finnish-style saunas exist in major cities globally. The cultural integration is more substantive in Finland and Nordic countries; the cultural pattern of social sauna use is part of the practice tradition.
  • Russian banya: Traditional Russian bathhouses in major Russian-speaking communities globally. The combined heat exposure plus venik (birch branch) practice provides distinct experience.
  • Japanese onsen and sento: Hot spring bathing (onsen) and public bathhouses (sento) in Japan. Korean-style spa centres (jjimjilbang) in major Korean diaspora communities.
  • Turkish hammam: Traditional Turkish bathhouses across the Mediterranean and Middle East, plus diaspora communities.
  • Korean jjimjilbang: Combined multi-modal thermal exposure facilities in Korean communities globally.
  • Roman bath restorations: Several restored Roman bath complexes operate as historical sites with limited bathing access; modern Roman-style thermal complexes exist in spa towns.

 

Specialised Thermal Exposure Facilities

  • Recovery centres: Combined sauna, cold plunge, and additional modalities. Growing commercial category. Quality varies substantially.
  • Cryotherapy facilities: Whole-body cryotherapy chambers in commercial wellness centres. Limited evidence base relative to cost; cold water immersion typically provides better-evidenced benefits at lower cost.
  • Hyperthermia treatment centres: Clinical facilities offering whole-body hyperthermia for medical applications. Limited availability; specific to medical indications.
  • Cold water swimming clubs: Particularly in Scandinavian and UK communities. Organised winter swimming with safety infrastructure.

 

Research Organisations and Institutions

  • The University of Eastern Finland: Jari Laukkanen’s research base. The KIHD cohort and the foundational Finnish sauna research.
  • The University of Copenhagen: Susanna Søberg’s research base. The cold thermogenesis research program.
  • Maastricht University: Wouter van Marken Lichtenbelt’s brown adipose tissue research program.
  • Stanford University: Craig Heller and Dennis Grahn’s palm cooling research.
  • The Radboud University Medical Center: Matthijs Kox’s WHM research base.
  • Kagoshima University: Chuwa Tei’s Waon therapy research base.

 

Apps and Digital Tools

Tracking Thermal Exposure

  • Oura Ring: Continuous body temperature tracking, HRV, broader physiological tracking. Useful for monitoring thermal exposure effects over time.
  • Whoop: HRV-focused tracking with sauna and cold exposure session logging.
  • Apple Watch: Body temperature, HRV through Health app integration.
  • Garmin: Compatible devices include temperature sensors and HRV tracking.

 

Specific Protocol Support

  • Plunge/Cold Plunge equipment apps: Some commercial cold plunge systems include companion apps for protocol tracking and temperature control.
  • Sauna timer apps: Various simple timer apps for specific protocols (GH release with multiple sessions and cooling breaks, contrast protocols, etc.).
  • Breathing apps: Wim Hof Method app for the WHM breath work practice. Various other breath work apps for separate practice. Reminder: breath work should be separated from water immersion by at least 15 minutes.

 

Educational Content

  • Huberman Lab podcast: Episodes on heat exposure, cold exposure, and broader thermal regulation accessible through podcast platforms and at hubermanlab.com.
  • FoundMyFitness: Topic pages and podcast episodes at foundmyfitness.com.
  • Susanna Søberg content: Books, podcasts, and online courses through soberginstitute.com.

 

Equipment Marketplaces

  • Cold plunge tubs: Multiple commercial options from $300 DIY chest freezer conversions to $10,000+ dedicated systems. Plunge, Ice Barrel, Cold Plunge are established brands in the higher-end commercial market. The DIY chest freezer approach works well for many users at substantially lower cost.
  • Saunas for home use: Traditional electric (Tylo, Helo, Harvia), traditional wood-burning (various), and infrared (Sunlighten, Clearlight, various others). Quality and price vary substantially.
  • Inflatable cold plunges: Lower-cost option for cold water immersion ($100-300).
  • Cooling devices: Arteria (commercial palm cooling), CoreControl (palm cooling for athletes), various budget alternatives.