The multifaceted benefits of passive heat therapies for extending the healthspan: A comprehensive review with a focus on Finnish sauna

References

• 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. DOI:10.1016/j.mayocp.2018.04.008
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Laukkanen JA. Does the combination of Finnish sauna bathing and other lifestyle factors confer additional health benefits? A review of the evidence. Mayo Clin Proc. 2023;98(6):915–926. DOI:10.1016/j.mayocp.2023.01.008
   PubMed Web of Science ®Google Scholar
• Scanu A, Tognolo L, Maccarone MC, et al. Immunological events, emerging pharmaceutical treatments and therapeutic potential of balneotherapy on osteoarthritis. Front Pharmacol. 2021;12:681871. DOI:10.3389/fphar.2021.681871
   PubMed Web of Science ®Google Scholar
• Maccarone MC, Scanu A, Coraci D, et al. The potential role of spa therapy in managing frailty in rheumatic patients: a scoping review. Healthcare (Basel). 2023;11(13):11. DOI:10.3390/healthcare11131899
   Google Scholar
• Kaeberlein M. How healthy is the healthspan concept? Geroscience. 2018;40(4):361–364. DOI:10.1007/s11357-018-0036-9
   PubMed Web of Science ®Google Scholar
• Ukai T, Iso H, Yamagishi K, et al. Habitual tub bathing and risks of incident coronary heart disease and stroke. Heart. 2020;106(10):732–737. DOI:10.1136/heartjnl-2019-315752
   PubMed Web of Science ®Google Scholar
• Kominami K, Takahiza E, Tabuchi M, et al. Blood pressure-lowering effect of repeated waon therapy in non-smokers with hypertension. Med. 2021;100(23):e26266. DOI:10.1097/MD.0000000000026266
   PubMed Web of Science ®Google Scholar
• Rocha Conceicao LS, de Queiroz JG, Neto MG, et al. Effect of waon therapy in individuals with heart failure: a systematic review. J Card Fail. 2018;24:204–206.
   PubMed Web of Science ®Google Scholar
• Miyata M, Tei C. Waon therapy for cardiovascular disease: - innovative therapy for the 21st Century -. Circ J. 2010;74(4):617–621. DOI:10.1253/circj.CJ-09-0939
   PubMed Web of Science ®Google Scholar
• Miyata M, Tei C. Pleiotropic effect of waon therapy. JMAJ. 2009;52:191–193.
   Google Scholar
• Sobajima M, Nozawa T, Fukui Y, et al. Waon therapy improves quality of life as well as cardiac function and exercise capacity in patients with chronic heart failure. Int Heart J. 2015;56(2):203–208. DOI:10.1536/ihj.14-266
   PubMed Web of Science ®Google Scholar
• Mooventhan A, Nivethitha L. Scientific evidence-based effects of hydrotherapy on various systems of the body. N Am J Med Sci. 2014;6(5):199–209. DOI:10.4103/1947-2714.132935
   PubMedGoogle Scholar
• Pandiaraja M, Vanitha A, Maheshkumar K, et al. Effect of the steam bath on resting cardiovascular parameters in healthy volunteers. Advances In Integrative Medicine. 2021;8(3):199–202. DOI:10.1016/j.aimed.2020.06.001
   Web of Science ®Google Scholar
• Zaccardi F, Laukkanen T, Willeit P, et al. Sauna bathing and incident hypertension: a prospective cohort study. Am J Hypertens. 2017;30(11):1120–1125. DOI:10.1093/ajh/hpx102
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Khan H, Zaccardi F, et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med. 2015;175(4):542–548. DOI:10.1001/jamainternmed.2014.8187
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Khan H, Zaccardi F, et al. Sauna bathing reduces the risk of stroke in Finnish men and women: a prospective cohort study. Neurology. 2018;90(22):e1937–e. 1944. DOI:10.1212/WNL.0000000000005606.
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen, J A., et al. Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men. Age And Ageing. 2016;46:245–249. DOI:10.1093/ageing/afw212 2
   Web of Science ®Google Scholar
• Kunutsor SK, Makikallio TH, Khan H, et al. Sauna bathing reduces the risk of venous thromboembolism: a prospective cohort study. Eur J Epidemiol. 2019;34(10):983–986. DOI:10.1007/s10654-019-00544-z
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Laukkanen T, Laukkanen JA. Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study. Eur J Epidemiol. 2017;32(12):1107–1111. DOI:10.1007/s10654-017-0311-6
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Jae SY, Laukkanen JA. Impact of sauna bathing on risk of pneumonia in men with low socioeconomic status: a cohort study. J Cardiopulm Rehabil Prev. 2021;41(4):289–291. DOI:10.1097/HCR.0000000000000611
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Laukkanen T, Laukkanen JA. Frequent sauna bathing may reduce the risk of pneumonia in middle-aged Caucasian men: the KIHD prospective cohort study. Respir Med. 2017;132:161–163. DOI:10.1016/j.rmed.2017.10.018
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Laukkanen JA, Kunutsor SK. Sauna bathing and risk of psychotic disorders: a prospective cohort study. Med Princ Pract. 2018;27(6):562–569. DOI:10.1159/000493392
   PubMed Web of Science ®Google Scholar
• Nurmikko T, Hietaharju A. Effect of exposure to sauna heat on neuropathic and rheumatoid pain. Pain. 1992;49(1):43–51. DOI:10.1016/0304-3959(92)90186-F
   PubMed Web of Science ®Google Scholar
• Isomaki H. The sauna and rheumatic diseases. Ann Clin Res. 1988;20(4):271–275.
   PubMedGoogle Scholar
• Kunutsor SK, Lavie CJ, Laukkanen J. Finnish sauna and COVID-19. Infez Med. 2021;29:160–162.
   PubMedGoogle Scholar
• Laitinen LA, Lindqvist A, Heino M. Lungs and ventilation in sauna. Ann Clin Res. 1988;20(4):244–248.
   PubMedGoogle Scholar
• Cox NJ, Oostendorp GM, Folgering HT, et al. Sauna to transiently improve pulmonary function in patients with obstructive lung disease. Arch Phys Med Rehabil. 1989;70(13):911–913.
   PubMed Web of Science ®Google Scholar
• Perasalo J. Traditional use of the sauna for hygiene and health in Finland. Ann Clin Res. 1988;20:220–223.
   PubMedGoogle Scholar
• Valtakari P. The sauna and bathing in different countries. Ann Clin Res. 1988;20(4):230–235.
   PubMedGoogle Scholar
• Hannuksela ML, Ellahham S. Benefits and risks of sauna bathing. Am J Med. 2001;110(2):118–126. DOI:10.1016/S0002-9343(00)00671-9
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Laukkanen J. Sauna, body & mind. Jyvaskyla: Docendo; 2020.
   Google Scholar
• Kukkonen-Harjula K, Kauppinen K. Health effects and risks of sauna bathing. Int J Circumpolar Health. 2006;65(3):195–205. DOI:10.3402/ijch.v65i3.18102
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Khan H, Laukkanen T, et al. 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. DOI:10.1080/07853890.2017.1387927
   PubMed Web of Science ®Google Scholar
• Lee E, Laukkanen T, Kunutsor SK, et al. Sauna exposure leads to improved arterial compliance: Findings from a non-randomised experimental study. Eur J Prev Cardiol. 2017;25(2):130–138. DOI:10.1177/2047487317737629
   PubMed Web of Science ®Google Scholar
• Fleming SA, Gutknecht NC. Naturopathy and the primary care practice. Prim Care. 2010;37(1):119–136. DOI:10.1016/j.pop.2009.09.002
   PubMed Web of Science ®Google Scholar
• Oyama J, Kudo Y, Maeda T, et al. Hyperthermia by bathing in a hot spring improves cardiovascular functions and reduces the production of inflammatory cytokines in patients with chronic heart failure. Heart Vessels. 2013;28(2):173–178. DOI:10.1007/s00380-011-0220-7
   PubMed Web of Science ®Google Scholar
• Inoue S, Takemoto M, Chishaki A, et al. Leg heating using far infra-red radiation in patients with chronic heart failure acutely improves the hemodynamics, vascular endothelial function, and oxidative stress. Intern Med. 2012;51(17):2263–2270. DOI:10.2169/internalmedicine.51.7115
   PubMed Web of Science ®Google Scholar
• OCEBM Levels of Evidence Working Group. The oxford 2011 levels of evidence. Oxford Centre for Evidence-Based Medicine. https://www.cebm.ox.ac.uk/resources/levels-of-evidence/ocebm-levels-of-evidence. Accessed on 8 October 2020.
   Google Scholar
• Gayda M, Bosquet L, Paillard F, et al. Effects of sauna alone versus postexercise sauna baths on short-term heart rate variability in patients with untreated hypertension. J Cardiopulm Rehabil Prev. 2012;32(3):147–154. DOI:10.1097/HCR.0b013e318251ffeb
   PubMed Web of Science ®Google Scholar
• Radtke T, Poerschke D, Wilhelm M, et al. Acute effects of Finnish sauna and cold-water immersion on haemodynamic variables and autonomic nervous system activity in patients with heart failure. Eur J Prev Cardiol. 2016;23(6):593–601. DOI:10.1177/2047487315594506
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Kunutsor SK, Zaccardi F, et al. Acute effects of sauna bathing on cardiovascular function. J Hum Hypertens. 2017;32(2):129–138. DOI:10.1038/s41371-017-0008-z.
   PubMed Web of Science ®Google Scholar
• Gayda M, Paillard F, Sosner P, et al. Effects of sauna alone and postexercise sauna baths on blood pressure and hemodynamic variables in patients with untreated hypertension. J Clin Hypertens. 2012;14(8):553–560. DOI:10.1111/j.1751-7176.2012.00637.x
   Web of Science ®Google Scholar
• Brunt VE, Howard MJ, Francisco MA, et al. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. J Physiol. 2016;594(18):5329–5342. DOI:10.1113/JP272453
   PubMed Web of Science ®Google Scholar
• Shin TW, Wilson M, Wilson TW. Are hot tubs safe for people with treated hypertension? CMAJ. 2003;169(12):1265–1268.
   PubMed Web of Science ®Google Scholar
• Pizzey FK, Smith EC, Ruediger SL, et al. The effect of heat therapy on blood pressure and peripheral vascular function: a systematic review and meta-analysis. Exp Physiol. 2021;106(6):1317–1334. DOI:10.1113/EP089424
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Kunutsor SK, Khan H, et al. 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. DOI:10.1186/s12916-018-1198-0
   PubMed Web of Science ®Google Scholar
• Laukkanen JA, Kunutsor SK. Is sauna bathing protective of sudden cardiac death? A review of the evidence. Prog Cardiovasc Dis. 2019;62(3):288–293. DOI:10.1016/j.pcad.2019.05.001
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Khan H, Zaccardi F, et al. Sauna bathing reduces the risk of stroke in Finnish men and women: a prospective cohort study. Neurology. 2018;90(22). In Press. DOI:10.1212/WNL.0000000000005606.
   PubMed Web of Science ®Google Scholar
• Ye WN, Thipse M, Mahdi MB, et al. Can heat therapy help patients with heart failure? Artif Organs. 2020;44(7):680–692. DOI:10.1111/aor.13659
   PubMed Web of Science ®Google Scholar
• Tei C, Shinsato T, Kihara T, et al. Successful thermal therapy for end-stage peripheral artery disease. J Cardiol. 2006;47(4):163–164.
   PubMedGoogle Scholar
• Tei C, Shinsato T, Miyata M, et al. Waon therapy improves peripheral arterial disease. J Am Coll Cardiol. 2007;50(22):2169–2171. DOI:10.1016/j.jacc.2007.08.025
   PubMed Web of Science ®Google Scholar
• Miyamoto H, Kai H, Nakaura H, et al. Safety and efficacy of repeated sauna bathing in patients with chronic systolic heart failure: a preliminary report. J Card Fail. 2005;11(6):432–436. DOI:10.1016/j.cardfail.2005.03.004
   PubMed Web of Science ®Google Scholar
• Haseba S, Sakakima H, Kubozono T, et al. Combined effects of repeated sauna therapy and exercise training on cardiac function and physical activity in patients with chronic heart failure. Disabil Rehabil. 2016;38(5):409–415. DOI:10.3109/09638288.2015.1044032
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Jae SY, Kurl S, et al. Frequent sauna bathing may mitigate the increased risk of mortality in men with elevated systolic blood pressure: a prospective cohort study. 2022 ( Unpublished).
   Google Scholar
• Koivisto VA. Sauna-induced acceleration in insulin absorption from subcutaneous injection site. British Med J. 1980;280(6229):1411–1413. DOI:10.1136/bmj.280.6229.1411
   PubMedGoogle Scholar
• Hooper PL. Hot-tub therapy for type 2 diabetes mellitus. N Engl J Med. 1999;341(12):924–925. DOI:10.1056/NEJM199909163411216
   PubMed Web of Science ®Google Scholar
• Ely BR, Clayton ZS, McCurdy CE, et al. Heat therapy improves glucose tolerance and adipose tissue insulin signaling in polycystic ovary syndrome. Am J Physiol Endocrinol Metab. 2019;317(1):E172–E182. DOI:10.1152/ajpendo.00549.2018
   PubMed Web of Science ®Google Scholar
• Sebok J, Edel Z, Vancsa S, et al. Heat therapy shows benefit in patients with type 2 diabetes mellitus: a systematic review and meta-analysis. Int J Hyperthermia. 2021;38(1):1650–1659. DOI:10.1080/02656736.2021.2003445
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Kauhanen J, Laukkanen JA. Sauna bathing, renal function and chronic kidney disease: cross-sectional and longitudinal findings from the KIHD study. Eur J Clin Invest. 2023;53(8):e14001. DOI:10.1111/eci.14001
   PubMed Web of Science ®Google Scholar
• Ravanelli N, Barry H, Schlader ZJ, et al. Impact of passive heat acclimation on markers of kidney function during heat stress. Exp Physiol. 2021;106(1):269–281. DOI:10.1113/EP088637
   PubMed Web of Science ®Google Scholar
• Knekt P, Jarvinen R, Rissanen H, et al. Does sauna bathing protect against dementia? Prev Med Rep. 2020;20:101221. DOI:10.1016/j.pmedr.2020.101221
   PubMedGoogle Scholar
• Hunt AP, Minett GM, Gibson OR, et al. Could heat therapy be an effective treatment for Alzheimer’s and Parkinson’s diseases? A narrative review. Front Physiol. 2019;10:1556. DOI:10.3389/fphys.2019.01556
   PubMed Web of Science ®Google Scholar
• Wust P, Hildebrandt B, Sreenivasa G, et al. Hyperthermia in combined treatment of cancer. Lancet Oncol. 2002;3(8):487–497. DOI:10.1016/S1470-2045(02)00818-5
   PubMed Web of Science ®Google Scholar
• Rao W, Deng ZS, Liu J. A review of hyperthermia combined with radiotherapy/chemotherapy on malignant tumors. Crit Rev Biomed Eng. 2010;38(1):101–116. DOI:10.1615/CritRevBiomedEng.v38.i1.80
   PubMedGoogle Scholar
• van der Zee J. Heating the patient: a promising approach? Ann Oncol. 2002;13:1173–1184.
   PubMed Web of Science ®Google Scholar
• Yi GY, Kim MJ, Kim HI, et al. Hyperthermia treatment as a promising anti-cancer strategy: therapeutic targets, perspective mechanisms and synergistic combinations in experimental approaches. Antioxid (Basel). 2022;11(4):11. DOI:10.3390/antiox11040625
   Google Scholar
• Ernst E, Pecho E, Wirz P, et al. Regular sauna bathing and the incidence of common colds. Ann Med. 1990;22(4):225–227. DOI:10.3109/07853899009148930
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Jae SY, Laukkanen JA. Attenuated risk of pneumonia due to inflammation by frequent sauna baths: a PROSPECTIVE COHORT STUDY. J Cardiopulm Rehabil Prev. 2022;42(1):59–63. DOI:10.1097/HCR.0000000000000598
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Laukkanen JA. High fitness levels, frequent sauna bathing and risk of pneumonia in a cohort study: are there potential implications for COVID-19? Eur J Clin Invest. 2021;51(3):e13490. DOI:10.1111/eci.13490
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Jae SY, Laukkanen JA. The interplay between socioeconomic status, sauna bathing and chronic obstructive pulmonary disease: a longitudinal study. J Cardiopulm Rehabil Prev. 2022;43(2):148–150. In Press. DOI:10.1097/HCR.0000000000000759.
   PubMed Web of Science ®Google Scholar
• Kunutsor SK, Laukkanen JA. Frequent sauna bathing may reduce chronic obstructive pulmonary disease risk: a prospective study. Eur J Clin Invest. 2023;53(5):e13940. DOI:10.1111/eci.13940
   PubMed Web of Science ®Google Scholar
• Tyrrell D, Barrow I, Arthur J. Local hyperthermia benefits natural and experimental common colds. BMJ. 1989;298(6683):1280–1283. DOI:10.1136/bmj.298.6683.1280
   PubMedGoogle Scholar
• Singh M, Singh M, Jaiswal N, et al.Heated, humidified air for the common coldCochrane Database Syst Rev 8 CD00172820178 DOI:10.1002/14651858.CD001728.pub6
   Google Scholar
• Umehara M, Yamaguchi A, Itakura S, et al. Repeated waon therapy improves pulmonary hypertension during exercise in patients with severe chronic obstructive pulmonary disease. J Cardiol. 2008;51(2):106–113. DOI:10.1016/j.jjcc.2008.01.004
   PubMed Web of Science ®Google Scholar
• Matsushita K, Masuda A, Tei C. Efficacy of waon therapy for fibromyalgia. Intern Med. 2008;47(16):1473–1476. DOI:10.2169/internalmedicine.47.1054
   PubMed Web of Science ®Google Scholar
• Cozzi F, Ciprian L, Carrara M, et al. Balneotherapy in chronic inflammatory rheumatic diseases—a narrative review. Int J Biometeorol. 2018;62(12):2065–2071. DOI:10.1007/s00484-018-1618-z
   PubMed Web of Science ®Google Scholar
• Masiero S, Vittadini F, Ferroni C, et al. The role of thermal balneotherapy in the treatment of obese patient with knee osteoarthritis. Int J Biometeorol. 2018;62(2):243–252. DOI:10.1007/s00484-017-1445-7
   PubMed Web of Science ®Google Scholar
• Hannuksela M, Vaananen A. The sauna, skin and skin diseases. Ann Clin Res. 1988;20(4):276–278.
   PubMedGoogle Scholar
• Kowatzki D, Macholdt C, Krull K, et al. Effect of regular sauna on epidermal barrier function and stratum corneum water-holding capacity in vivo in humans: a controlled study. Dermatology. 2008;217(2):173–180. DOI:10.1159/000137283
   PubMed Web of Science ®Google Scholar
• Brunt VE, Eymann TM, Francisco MA, et al.Passive heat therapy improves cutaneous microvascular function in sedentary humans via improved nitric oxide-dependent dilationJ Appl Physiol 19852016121716–723
   PubMed Web of Science ®Google Scholar
• Putkonen PT, Elomaa E. Sauna and physiological sleep: increased slow-wave sleep after heat exposure. In: ValtakariH, Collan Y.P, editors. Sauna studies. Helsinki: The Finnish Sauna Society; 1976.
   Google Scholar
• Mishima Y, Hozumi S, Shimizu T, et al. Passive body heating ameliorates sleep disturbances in patients with vascular dementia without circadian phase-shifting. Am J Geriatr Psychiatry. 2005;13(5):369–376. DOI:10.1097/00019442-200505000-00005
   PubMed Web of Science ®Google Scholar
• Liao WC. Effects of passive body heating on body temperature and sleep regulation in the elderly: a systematic review. Int J Nurs Stud. 2002;39(8):803–810. DOI:10.1016/S0020-7489(02)00023-8
   PubMed Web of Science ®Google Scholar
• Liu J, Zhou J, Yao J, et al. Impact of meteorological factors on the COVID-19 transmission: a multi-city study in China. Sci Total Environ. 2020;726:138513. DOI:10.1016/j.scitotenv.2020.138513
   PubMed Web of Science ®Google Scholar
• Jaakkola K, Saukkoriipi A, Jokelainen J, et al. Decline in temperature and humidity increases the occurrence of influenza in cold climate. Environ Health. 2014;13(1):22. DOI:10.1186/1476-069X-13-22
   PubMedGoogle Scholar
• Chan KH, Peiris JS, Lam SY, et al.The effects of temperature and relative humidity on the viability of the SARS CoronavirusAdv Virol2011 20111–72011 DOI:10.1155/2011/734690
   Google Scholar
• Kunutsor SK, Laukkanen T, Laukkanen J. Longitudinal associations of sauna bathing with inflammation and oxidative stress: the KIHD prospective cohort study. Ann Med. 2018;50(5):437–442. DOI:10.1080/07853890.2018.1489143
   PubMed Web of Science ®Google Scholar
• Laukkanen JA, Laukkanen T. Sauna bathing and systemic inflammation. Eur J Epidemiol. 2018;33(3):351–353. DOI:10.1007/s10654-017-0335-y
   PubMed Web of Science ®Google Scholar
• Mehta P, McAuley DF, Brown M, et al. COVID-19: consider cytokine storm syndromes and immunosuppression. Lancet. 2020;395(10229):1033–1034. DOI:10.1016/S0140-6736(20)30628-0
   PubMed Web of Science ®Google Scholar
• Hagglund H. Sauna bathing and lower urinary tract symptoms- the heat is on? Scand J Urol. 2022;56(2):168. DOI:10.1080/21681805.2022.2028898
   PubMed Web of Science ®Google Scholar
• Poyhonen A, Akerla J, Koskimaki J, et al. Sauna habits/bathing and changes in lower urinary tract symptoms – Tampere ageing male urologic study (TAMUS). Scand J Urol. 2022;56(1):77–82. DOI:10.1080/21681805.2021.2002403
   PubMed Web of Science ®Google Scholar
• Kanji G, Weatherall M, Peter R, et al. Efficacy of regular sauna bathing for chronic tension-type headache: a randomized controlled study. J Altern Complement Med. 2015;21(2):103–109. DOI:10.1089/acm.2013.0466
   PubMed Web of Science ®Google Scholar
• Strandberg TE, Strandberg A, Pitkala K, et al. Sauna bathing, health, and quality of life among octogenarian men: the Helsinki Businessmen Study. Aging Clin Exp Res. 2017;30(9):1053–1057. DOI:10.1007/s40520-017-0855-z
   PubMed Web of Science ®Google Scholar
• Beever R. The effects of repeated thermal therapy on quality of life in patients with type II diabetes mellitus. J Altern Complement Med. 2010;16(6):677–681. DOI:10.1089/acm.2009.0358
   PubMed Web of Science ®Google Scholar
• Masuda A, Nakazato M, Kihara T, et al. Repeated thermal therapy diminishes appetite loss and subjective complaints in mildly depressed patients. Psychosom Med. 2005;67(4):643–647. DOI:10.1097/01.psy.0000171812.67767.8f
   PubMed Web of Science ®Google Scholar
• Lee E, Willeit P, Laukkanen T, et al. Acute effects of exercise and sauna as a single intervention on arterial compliance. Eur J Prev Cardiol. 2020;27(10):1104–1107. DOI:10.1177/2047487319855454
   PubMed Web of Science ®Google Scholar
• Lee E, Kostensalo J, Willeit P, et al. Standalone sauna vs exercise followed by sauna on cardiovascular function in non-naïve sauna users: A comparison of acute effects. Health Sci Rep. 2021;4(4):e393. DOI:10.1002/hsr2.393
   PubMedGoogle Scholar
• Stanley J, Halliday A, D’Auria S, et al. Effect of sauna-based heat acclimation on plasma volume and heart rate variability. Eur J Appl Physiol. 2015;115(4):785–794. DOI:10.1007/s00421-014-3060-1
   PubMed Web of Science ®Google Scholar
• Rissanen JA, Hakkinen K, Laukkanen JA, et al. Acute hemodynamic responses to combined exercise and sauna. Int J Sports Med. 2020;41(12):824–831. DOI:10.1055/a-1186-1716
   PubMed Web of Science ®Google Scholar
• Lee E, Kolunsarka IA, Kostensalo J, et al. 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. DOI:10.1152/ajpregu.00076.2022
   PubMed Web of Science ®Google Scholar
• Mero A, Tornberg J, Mantykoski M, et al. Effects of far-infrared sauna bathing on recovery from strength and endurance training sessions in men. Springerplus. 2015;4(1):321. DOI:10.1186/s40064-015-1093-5
   PubMedGoogle Scholar
• Pilch W, Pokora I, Szygula Z, et al. Effect of a single Finnish sauna session on white blood cell profile and cortisol levels in athletes and non-athletes. J Hum Kinet. 2013;39(1):127–135. DOI:10.2478/hukin-2013-0075
   PubMed Web of Science ®Google Scholar
• Laukkanen J, Laukkanen T, Khan H, et al. Combined effect of sauna bathing and cardiorespiratory fitness on the risk of sudden cardiac deaths in Caucasian men: a long-term prospective cohort study. Prog Cardiovasc Dis. 2018;60(6):635–641. DOI:10.1016/j.pcad.2018.03.005
   PubMed Web of Science ®Google Scholar
• Kubozono T, Miyata M, Haseba J, et al. Effect and safety of combination of waon therapy and exercise training in patients with chronic heart failure. J Card Fail. 2011;17(9):S135. DOI:10.1016/j.cardfail.2011.06.632
   PubMed Web of Science ®Google Scholar
• Sakurai R, Fujiwara Y, Saito K, et al. Effects of a comprehensive intervention program, including hot bathing, on overweight adults: a randomized controlled trial. Geriatr Gerontol Int. 2013;13(3):638–645. DOI:10.1111/j.1447-0594.2012.00955.x
   PubMed Web of Science ®Google Scholar
• Sutkowy P, Woźniak A, Boraczyński T, et al. The effect of a single Finnish sauna bath after aerobic exercise on the oxidative status in healthy men. Scand J Clin Lab Invest. 2014;74(2):89–94. DOI:10.3109/00365513.2013.860616
   PubMed Web of Science ®Google Scholar
• Masuda A, Miyata M, Kihara T, et al. Repeated sauna therapy reduces urinary 8-epi-prostaglandin F2.ALPHA. Jpn Heart J. 2004;45(2):297–303. DOI:10.1536/jhj.45.297
   PubMedGoogle Scholar
• Miyata M, Kihara T, Kubozono T, et al. Beneficial effects of waon therapy on patients with chronic heart failure: results of a prospective multicenter study. J Cardiol. 2008;52(2):79–85. DOI:10.1016/j.jjcc.2008.07.009
   PubMed Web of Science ®Google Scholar
• Lee E, Laukkanen T, Kunutsor SK, et al. Sauna exposure leads to improved arterial compliance: findings from a non-randomised experimental study. Eur J Prev Cardiol. 2018;25(2):130–138. DOI:10.1177/2047487317737629
   PubMed Web of Science ®Google Scholar
• Ganio MS, Brothers RM, Shibata S, et al. Effect of passive heat stress on arterial stiffness. Exp Physiol. 2011;96(9):919–926. DOI:10.1113/expphysiol.2011.057091
   PubMed Web of Science ®Google Scholar
• Ohori T, Nozawa T, Ihori H, et al. Effect of repeated sauna treatment on exercise tolerance and endothelial function in patients with chronic heart failure. Am J Cardiol. 2012;109(1):100–104. DOI:10.1016/j.amjcard.2011.08.014
   PubMed Web of Science ®Google Scholar
• Imamura M, Biro S, Kihara T, et al. Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors. J Am Coll Cardiol. 2001;38(4):1083–1088. DOI:10.1016/S0735-1097(01)01467-X
   PubMed Web of Science ®Google Scholar
• Kihara T, Biro S, Imamura M, et al. Repeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failure. J Am Coll Cardiol. 2002;39(5):754–759. DOI:10.1016/S0735-1097(01)01824-1
   PubMed Web of Science ®Google Scholar
• Brunt VE, Weidenfeld-Needham KM, Comrada LN, et al. Serum from young, sedentary adults who underwent passive heat therapy improves endothelial cell angiogenesis via improved nitric oxide bioavailability. Temperature. 2019;6(2):169–178. DOI:10.1080/23328940.2019.1614851
   Google Scholar
• Gryka D, Pilch W, Szarek M, et al. The effect of sauna bathing on lipid profile in young, physically active, male subjects. Int J Occup Med Environ Health. 2014;27(4):608–618. DOI:10.2478/s13382-014-0281-9
   PubMed Web of Science ®Google Scholar
• Pilch W, Szygula Z, Klimek AT, et al. Changes in the lipid profile of blood serum in women taking sauna baths of various duration. Int J Occup Med Environ Health. 2010;23(2):167–174. DOI:10.2478/v10001-010-0020-9
   PubMed Web of Science ®Google Scholar
• Scoon GS, Hopkins WG, Mayhew S, et al. Effect of post-exercise sauna bathing on the endurance performance of competitive male runners. J Sci Med Sport. 2007;10(4):259–262. DOI:10.1016/j.jsams.2006.06.009
   PubMed Web of Science ®Google Scholar
• Crandall CG, González-Alonso J. Cardiovascular function in the heat-stressed human. Acta Physiol (Oxf). 2010;199(4):407–423. DOI:10.1111/j.1748-1716.2010.02119.x
   PubMed Web of Science ®Google Scholar
• Kukkonen-Harjula K, Kauppinen K. How the sauna affects the endocrine system. Ann Clin Res. 1988;20(4):262–266.
   PubMedGoogle Scholar
• Tei C, Horikiri Y, Park JC, et al. Acute hemodynamic improvement by thermal vasodilation in congestive heart failure. Circulation. 1995;91(10):2582–2590. DOI:10.1161/01.CIR.91.10.2582
   PubMed Web of Science ®Google Scholar
• Von E. Quantitation of stress by Catecholamine Analysis. Clin Pharmacol Ther. 1964;5(4):398–404. DOI:10.1002/cpt196454398
   PubMed Web of Science ®Google Scholar
• Laukkanen T, Lipponen J, Kunutsor SK, et al. Recovery from sauna bathing favorably modulates cardiac autonomic nervous system. Complement Ther Med. 2019;45:190–197. DOI:10.1016/j.ctim.2019.06.011
   PubMed Web of Science ®Google Scholar
• Genuis SJ, Birkholz D, Rodushkin I, et al. Blood, urine, and sweat (BUS) study: monitoring and elimination of bioaccumulated toxic elements. Arch Environ Contam Toxicol. 2011;61(2):344–357. DOI:10.1007/s00244-010-9611-5
   PubMed Web of Science ®Google Scholar
• Patrick RP, Johnson TL. Sauna use as a lifestyle practice to extend healthspan. Exp Gerontol. 2021;154:111509. DOI:10.1016/j.exger.2021.111509
   PubMed Web of Science ®Google Scholar
• Kojima D, Nakamura T, Banno M, et al. Head-out immersion in hot water increases serum BDNF in healthy males. Int J Hyperthermia. 2018;34(6):834–839. DOI:10.1080/02656736.2017.1394502
   PubMed Web of Science ®Google Scholar
• Kauppinen K, Vuori I. Man in the sauna. Ann Clin Res. 1986;18(4):173–185.
   PubMedGoogle Scholar
• Rissanen JA, Hakkinen A, Laukkanen J, et al. Acute neuromuscular and hormonal responses to different exercise loadings followed by a sauna. J Strength Cond Res. 2020;34(2):313–322. DOI:10.1519/JSC.0000000000003371
   PubMed Web of Science ®Google Scholar
• Huhtaniemi IT, Laukkanen JA. Endocrine effects of sauna bath. Current Opinion In Endocrine And Metabolic Research. 2020;11:15–20. DOI:10.1016/j.coemr.2019.12.004
   Google Scholar
• Vescovi PP, DiGennaro C, Hormonal CV. (ACTH, cortisol, beta-endorphin, and met-enkephalin) and cardiovascular responses to hyperthermic stress in chronic alcoholics. Alcohol Clin Exp Res. 1997;21:1195–1198.
   PubMed Web of Science ®Google Scholar
• Kappel M, Gyhrs A, Galbo H, et al. The response on glucoregulatory hormones of in vivo whole body hyperthermia. Int J Hyperthermia. 1997;13(4):413–421. DOI:10.3109/02656739709046542
   PubMed Web of Science ®Google Scholar
• Rivas E, Newmire DE, Crandall CG, et al. An acute bout of whole body passive hyperthermia increases plasma leptin, but does not alter glucose or insulin responses in obese type 2 diabetics and healthy adults. J Therm Biol. 2016;59:26–33. DOI:10.1016/j.jtherbio.2016.04.010
   PubMed Web of Science ®Google Scholar
• Laatikainen T, Salminen K, Kohvakka A, et al. Response of plasma endorphins, prolactin and catecholamines in women to intense heat in a sauna. Eur J Appl Physiol Occup Physiol. 1988;57(1):98–102. DOI:10.1007/BF00691246
   PubMed Web of Science ®Google Scholar
• Salleh MR. Life event, stress and illness. Malays J Med Sci. 2008;15:9–18.
   PubMedGoogle Scholar
• Vuori I. Sauna bather’s circulation. Ann Clin Res. 1988;20:249–256. 4
   PubMedGoogle Scholar
• Ketelhut S, Ketelhut RG. The blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exercise. Complement Ther Med. 2019;44:218–222. DOI:10.1016/j.ctim.2019.05.002
   PubMed Web of Science ®Google Scholar
• Morimoto RI. Cells in stress: transcriptional activation of heat shock genes. Sci. 1993;259(5100):1409–1410. DOI:10.1126/science.8451637
   PubMed Web of Science ®Google Scholar
• Faulkner SH, Jackson S, Fatania G, et al. The effect of passive heating on heat shock protein 70 and interleukin-6: a possible treatment tool for metabolic diseases? Temperature. 2017;4(3):292–304. DOI:10.1080/23328940.2017.1288688
   Google Scholar
• Calderwood SK, Murshid A, Prince T. The shock of aging: molecular chaperones and the heat shock response in longevity and aging–a mini-review. Gerontology. 2009;55(5):550–558. DOI:10.1159/000225957
   PubMed Web of Science ®Google Scholar
• Madeo F, Zimmermann A, Maiuri MC, et al. Essential role for autophagy in life span extension. J Clin Invest. 2015;125(1):85–93. DOI:10.1172/JCI73946
   PubMed Web of Science ®Google Scholar
• Sies H. Oxidative stress: a concept in redox biology and medicine. Redox Biol. 2015;4:180–183. DOI:10.1016/j.redox.2015.01.002
   PubMed Web of Science ®Google Scholar
• Marchant ED, Nelson WB, Hyldahl RD, et al. Passive heat stress induces mitochondrial adaptations in skeletal muscle. Int J Hyperthermia. 2023;40(1):2205066. DOI:10.1080/02656736.2023.2205066
   PubMed Web of Science ®Google Scholar
• Gonzalez-Freire M, de Cabo R, Bernier M, et al. Reconsidering the role of mitochondria in aging. J Gerontol A Biol Sci Med Sci. 2015;70(11):1334–1342. DOI:10.1093/gerona/glv070
   PubMed Web of Science ®Google Scholar
• Dai DF, Chiao YA, Marcinek DJ, et al. Mitochondrial oxidative stress in aging and healthspan. Longev Healthspan. 2014;3(1):6. DOI:10.1186/2046-2395-3-6
   PubMedGoogle Scholar
• Dai DF, Rabinovitch PS, Ungvari Z, et al. Mitochondria and cardiovascular aging. Circ Res. 2012;110(8):1109–1124. DOI:10.1161/CIRCRESAHA.111.246140
   PubMed Web of Science ®Google Scholar
• Hubbard BP, Sinclair DA. Small molecule SIRT1 activators for the treatment of aging and age-related diseases. Trends Pharmacol Sci. 2014;35(3):146–154. DOI:10.1016/j.tips.2013.12.004
   PubMed Web of Science ®Google Scholar
• Schmid JP. Some like it hot: cardiovascular health benefits of Finnish sauna. Eur J Prev Cardiol. 2018;25(2):127–129. DOI:10.1177/2047487317742501
   PubMed Web of Science ®Google Scholar
• Shoenfeld Y, Sohar E, Ohry A, et al. Heat stress: comparison of short exposure to severe dry and wet heat in saunas. Arch Phys Med Rehabil. 1976;57(3):126–129.
   PubMed Web of Science ®Google Scholar
• Luurila OJ. The sauna and the heart. J Intern Med. 1992;231(4):319–320. DOI:10.1111/j.1365-2796.1992.tb00938.x
   PubMed Web of Science ®Google Scholar
• Kihara T, Biro S, Ikeda Y, et al. Effects of repeated sauna treatment on ventricular arrhythmias in patients with chronic heart failure. Circ J. 2004;68(12):1146–1151. DOI:10.1253/circj.68.1146
   PubMed Web of Science ®Google Scholar
• Ylikahri R, Heikkonen E, Soukas A. The sauna and alcohol. Ann Clin Res. 1988;20(4):287–291.
   PubMedGoogle Scholar
• Roine R, Luurila OJ, Suokas A, et al. Alcohol and sauna bathing: effects on cardiac rhythm, blood pressure, and serum electrolyte and cortisol concentrations. J Intern Med. 1992;231(4):333–338. DOI:10.1111/j.1365-2796.1992.tb00941.x
   PubMed Web of Science ®Google Scholar
• Eisalo A, Luurila OJ. The Finnish sauna and cardiovascular diseases. Ann Clin Res. 1988;20(4):267–270.
   PubMedGoogle Scholar
• Papp A. Sauna-related burns: a review of 154 cases treated in Kuopio University Hospital burn center 1994–2000. Burns. 2002;28(1):57–59. DOI:10.1016/S0305-4179(01)00073-0
   PubMed Web of Science ®Google Scholar
• Lateef F. Post exercise ice water immersion: is it a form of active recovery? J Emerg Trauma Shock. 2010;3(3):302. DOI:10.4103/0974-2700.66570
   PubMedGoogle Scholar
• Keatinge WR, Evans M. The respiratory and cardiovascular response to immersion in cold and warm water. Q J Exp Physiol Cogn Med Sci. 1961;46(1):83–94. DOI:10.1113/expphysiol.1961.sp001519
   PubMedGoogle Scholar
• Schmid JP, Morger C, Noveanu M, et al. Haemodynamic and arrhythmic effects of moderately cold (22°C) water immersion and swimming in patients with stable coronary artery disease and heart failure. Eur J Heart Fail. 2009;11(9):903–909. DOI:10.1093/eurjhf/hfp114
   PubMed Web of Science ®Google Scholar
• Keast ML, Adamo KB. The Finnish sauna bath and its use in patients with cardiovascular disease. J Cardiopulm Rehabil. 2000;20(4):225–230. DOI:10.1097/00008483-200007000-00002
   PubMedGoogle Scholar
• Vuori I. The heart and the cold. Ann Clin Res. 1987;19(3):156–162.
   PubMedGoogle Scholar
• Vuori I. Healthy and unhealthy sauna bathing. Ann Clin Res. 1988;20:217–219.
   PubMedGoogle Scholar
• Akerman AP, Tipton M, Minson CT, et al. Heat stress and dehydration in adapting for performance: good, bad, both, or neither? Temperature. 2016;3(3):412–436. DOI:10.1080/23328940.2016.1216255
   PubMedGoogle Scholar
• Leyk D. Health risks and interventions in exertional heat stress. Dtsch Arztebl Int. 2019;116:537–544. DOI:10.3238/arztebl.2019.0537
   PubMed Web of Science ®Google Scholar
• Garcia CK, Renteria LI, Leite-Santos G, et al. Exertional heat stroke: pathophysiology and risk factors. BMJ Med. 2022;1(1):e000239. DOI:10.1136/bmjmed-2022-000239
   PubMedGoogle Scholar
• Meade RD, Akerman AP, Notley SR, et al. Physiological factors characterizing heat-vulnerable older adults: a narrative review. Environ Int. 2020;144:105909. DOI:10.1016/j.envint.2020.105909
   PubMed Web of Science ®Google Scholar
• Fjallbrant H, Akerstrom M, Svensson E, et al. Hot tub lung: an occupational hazard. Eur Respir Rev. 2013;22(127):88–90. DOI:10.1183/09059180.00002312
   PubMedGoogle Scholar
• Turner B, Pennefather J, Edmonds C. Cardiovascular effects of hot water immersion (suicide soup). Med J Aust. 1980;2(1):39–40. DOI:10.5694/j.1326-5377.1980.tb131813.x
   PubMed Web of Science ®Google Scholar
• Baartmans M, Kerkhof E, Vloemans J, et al. Steam inhalation therapy: severe scalds as an adverse side effect. Br J Gen Pract. 2012;62(600):e473–477. DOI:10.3399/bjgp12X652337
   PubMed Web of Science ®Google Scholar
• Patel CJ, Ioannidis JP. Placing epidemiological results in the context of multiplicity and typical correlations of exposures. J Epidemiol Community Health. 2014;68(11):1096–1100. DOI:10.1136/jech-2014-204195
   PubMed Web of Science ®Google Scholar
• McAlindon TE, Bannuru RR, Sullivan MC, et al. OARSI guidelines for the non-surgical management of knee osteoarthritis. Osteoarthr Cartil. 2014;22(3):363–388. DOI:10.1016/j.joca.2014.01.003
   PubMed Web of Science ®Google Scholar