{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T08:00:21Z","timestamp":1785484821960,"version":"3.56.0"},"reference-count":45,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T00:00:00Z","timestamp":1785456000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T00:00:00Z","timestamp":1785456000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"abstract":"Abstract<\/jats:title>\n \n Far\u2010infrared (FIR) saunas are increasingly used as a passive heating and \u2018wellness\u2019 modality, yet their capacity to elevate core temperature remains unclear, particularly given prior work at lower temperatures (\u223c45\u00b0C) reports limited net heat storage. We therefore examined whether FIR sauna exposure at an ambient temperature more typical of traditional sauna bathing (65\u00b0C) increases core (rectal) temperature and evokes thermoregulatory, cardiovascular, haematological and perceptual responses associated with heat strain. Twelve healthy adults (6 female) completed a single 45\u2010min FIR sauna exposure. Rectal temperature, skin temperature, heart rate, blood pressure, plasma volume changes and perceptual measures were assessed throughout. Rectal temperature increased by 1.4\u00b0C\u00a0(95% CI: 0.9, 1.8;\n P\u00a0<\/jats:italic>\n <\u00a00.001), with elevations evident from \u223c20\u00a0min. Skin temperature rose rapidly (+7.4\u00b0C [95% CI: 5.4,\u00a09.5] at 5\u00a0min;\n P\u00a0<\/jats:italic>\n <\u00a00.001) and remained elevated thereafter. Heart rate increased from 74\u00a0\u00b1\u00a015 to 153\u00a0\u00b1\u00a020\u00a0bpm (\n P\u00a0<\/jats:italic>\n <\u00a00.001), while mean arterial pressure decreased immediately post\u2010exposure (\u22129\u00a0mmHg\u00a0[95% CI: \u22122, \u221216];\n P\u00a0<\/jats:italic>\n =\u00a00.012), driven by reductions in diastolic pressure. Plasma volume contracted by \u221211.6% (95% CI: \u221215.9, \u22127.2;\n P\u00a0<\/jats:italic>\n <\u00a00.001), with a sweat rate of 1.4\u00a0\u00b1\u00a0 0.5 L\u00a0h\n \u2212<\/jats:sup>\n 1<\/jats:sup>\n . Thermal sensation and discomfort increased to \u2018extremely hot\u2019 and \u2018extremely uncomfortable\u2019, respectively (\n P\u00a0<\/jats:italic>\n <\u00a00.001). In summary, FIR sauna exposure at 65\u00b0C elicits substantial increases in rectal temperature and systemic physiological strain comparable to values previously reported in the passive heating literature. These findings indicate that the effectiveness of FIR sauna to increase core temperature is governed by the thermal load imposed, supporting its potential as a heat\u2010based intervention when applied at sufficiently high temperatures.\n <\/jats:p>","DOI":"10.1113\/ep094028","type":"journal-article","created":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T07:36:52Z","timestamp":1785483412000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Far\u2010infrared sauna exposure at 65\u00b0C elevates core temperature"],"prefix":"10.1113","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4053-2410","authenticated-orcid":false,"given":"Elliott J.","family":"Jenkins","sequence":"first","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-6207-1324","authenticated-orcid":false,"given":"Joseph A.","family":"Killick","sequence":"additional","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sally R.","family":"Grimm","sequence":"additional","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sam R.","family":"Davies","sequence":"additional","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-9932-770X","authenticated-orcid":false,"given":"Jemima A.","family":"Benson","sequence":"additional","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1667-294X","authenticated-orcid":false,"given":"Joshua C.","family":"Tremblay","sequence":"additional","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0818-6420","authenticated-orcid":false,"given":"Mike","family":"Stembridge","sequence":"additional","affiliation":[{"name":"Cardiff School of Sport and Health Sciences Cardiff Metropolitan University Cardiff UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,7,31]]},"reference":[{"issue":"1","key":"e_1_2_10_2_1","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1080\/00140139.2022.2058096","article-title":"Post\u2010exercise, passive heat acclimation with sauna or hot\u2010water immersion provide comparable adaptations to performance in the heat in a military context","volume":"66","author":"Ashworth E.","year":"2023","journal-title":"Ergonomics"},{"issue":"1","key":"e_1_2_10_3_1","doi-asserted-by":"crossref","first-page":"R20","DOI":"10.1152\/ajpregu.00012.2025","article-title":"Comparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalities","volume":"329","author":"Atencio J. K.","year":"2025","journal-title":"American Journal of Physiology\u2010Regulatory, Integrative and Comparative Physiology"},{"issue":"7","key":"e_1_2_10_4_1","first-page":"691","article-title":"Far\u2010infrared saunas for treatment of cardiovascular risk factors: Summary of published evidence","volume":"55","author":"Beever R.","year":"2009","journal-title":"Canadian Family Physician"},{"issue":"1","key":"e_1_2_10_5_1","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1016\/j.jsams.2007.08.017","article-title":"Heat stress and strain in exercise and sport","volume":"11","author":"Brotherhood J. R.","year":"2008","journal-title":"Journal of Science and Medicine in Sport"},{"issue":"18","key":"e_1_2_10_6_1","doi-asserted-by":"crossref","first-page":"5329","DOI":"10.1113\/JP272453","article-title":"Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans","volume":"594","author":"Brunt V. E.","year":"2016","journal-title":"The Journal of Physiology"},{"issue":"1","key":"e_1_2_10_7_1","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.jsams.2007.07.003","article-title":"Wet\u2010bulb globe temperature (WBGT)\u2014its history and its limitations","volume":"11","author":"Budd G. M.","year":"2008","journal-title":"Journal of Science and Medicine in Sport"},{"issue":"3","key":"e_1_2_10_8_1","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1113\/jphysiol.1977.sp011732","article-title":"Thermoregulatory responses as a function of core temperature in humans","volume":"265","author":"Cabanac M.","year":"1977","journal-title":"The Journal of Physiology"},{"issue":"5","key":"e_1_2_10_9_1","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1113\/EP089992","article-title":"Acute physiological and psychophysical responses to different modes of heat stress","volume":"107","author":"Campbell H. A.","year":"2022","journal-title":"Experimental Physiology"},{"issue":"5","key":"e_1_2_10_10_1","doi-asserted-by":"crossref","first-page":"329","DOI":"10.2165\/00007256-200029050-00004","article-title":"The thermophysiology of uncompensable heat stress: Physiological manipulations and individual characteristics","volume":"29","author":"Cheung S. S.","year":"2000","journal-title":"Sports Medicine"},{"issue":"4","key":"e_1_2_10_11_1","doi-asserted-by":"crossref","first-page":"407","DOI":"10.1111\/j.1748-1716.2010.02119.x","article-title":"Cardiovascular function in the heat\u2010stressed human","volume":"199","author":"Crandall C. G.","year":"2010","journal-title":"Acta Physiologica"},{"issue":"1","key":"e_1_2_10_12_1","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1002\/j.2040-4603.2015.tb00604.x","article-title":"Human cardiovascular responses to passive heat stress","volume":"5","author":"Crandall C. G.","year":"2011","journal-title":"Comprehensive Physiology"},{"issue":"2","key":"e_1_2_10_13_1","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1152\/jappl.1974.37.2.247","article-title":"Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration","volume":"37","author":"Dill D. B.","year":"1974","journal-title":"Journal of Applied Physiology"},{"issue":"4","key":"e_1_2_10_14_1","first-page":"45","article-title":"Mechanisms of heat exchange: Biophysics and physiology","volume":"102","author":"Gagge A. P.","year":"2010","journal-title":"Comprehensive Physiology"},{"issue":"1","key":"e_1_2_10_15_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/0013-9351(67)90002-3","article-title":"Comfort and thermal sensations and associated physiological responses at various ambient temperatures","volume":"1","author":"Gagge A. P.","year":"1967","journal-title":"Environmental Research"},{"issue":"9","key":"e_1_2_10_16_1","doi-asserted-by":"crossref","first-page":"1571","DOI":"10.1113\/jphysiol.2010.186965","article-title":"Obligatory role of hyperaemia and shear stress in microvascular adaptation to repeated heating in humans","volume":"588","author":"Green D. J.","year":"2010","journal-title":"The Journal of Physiology"},{"issue":"2","key":"e_1_2_10_17_1","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/S0002-9343(00)00671-9","article-title":"Benefits and risks of sauna bathing","volume":"110","author":"Hannuksela M. L.","year":"2001","journal-title":"The American Journal of Medicine"},{"key":"e_1_2_10_18_1","doi-asserted-by":"crossref","first-page":"1851","DOI":"10.3389\/fphys.2018.01851","article-title":"Passive heating: Reviewing practical heat acclimation strategies for endurance athletes","volume":"9","author":"Heathcote S. L.","year":"2018","journal-title":"Frontiers in Physiology"},{"issue":"5","key":"e_1_2_10_19_1","doi-asserted-by":"crossref","first-page":"R629","DOI":"10.1152\/ajpregu.00115.2017","article-title":"Effects of heat and cold on health, with special reference to Finnish sauna bathing","volume":"314","author":"Heinonen I.","year":"2018","journal-title":"American Journal of Physiology\u2010Regulatory, Integrative and Comparative Physiology"},{"issue":"2","key":"e_1_2_10_20_1","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1113\/EP090969","article-title":"Delineating the impacts of air temperature and humidity for endurance exercise","volume":"108","author":"Jenkins E. J.","year":"2022","journal-title":"Experimental Physiology"},{"key":"e_1_2_10_21_1","doi-asserted-by":"publisher","DOI":"10.1113\/JP288997"},{"key":"e_1_2_10_22_1","doi-asserted-by":"publisher","DOI":"10.1113\/JP289874"},{"issue":"4","key":"e_1_2_10_23_1","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1113\/EP089993","article-title":"A crossover control study of three methods of heat acclimation on the magnitude and kinetics of adaptation","volume":"107","author":"Kissling L. S.","year":"2022","journal-title":"Experimental physiology"},{"issue":"1","key":"e_1_2_10_24_1","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1080\/23328940.2020.1826287","article-title":"Sweat rate and sweat composition following active or passive heat re\u2010acclimation: A pilot study","volume":"8","author":"Klous L.","year":"2021","journal-title":"Temperature"},{"issue":"1","key":"e_1_2_10_25_1","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1080\/23328940.2023.2300623","article-title":"The multifaceted benefits of passive heat therapies for extending the healthspan: A comprehensive review with a focus on Finnish sauna","volume":"11","author":"Laukkanen J. A.","year":"2024","journal-title":"Temperature"},{"issue":"4","key":"e_1_2_10_26_1","doi-asserted-by":"crossref","first-page":"542","DOI":"10.1001\/jamainternmed.2014.8187","article-title":"Association between sauna bathing and fatal cardiovascular and all\u2010cause mortality events","volume":"175","author":"Laukkanen T.","year":"2015","journal-title":"JAMA Internal Medicine"},{"issue":"4","key":"e_1_2_10_27_1","first-page":"240","article-title":"Human thermoregulation in sauna","volume":"20","author":"Lepp\u00e4luoto J.","year":"1988","journal-title":"Annals of Clinical Research"},{"issue":"1","key":"e_1_2_10_28_1","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1111\/j.1748-1716.1986.tb07952.x","article-title":"Some cardiovascular and metabolic effects of repeated sauna bathing","volume":"128","author":"Lepp\u00e4luoto J.","year":"1986","journal-title":"Acta Physiologica Scandinavica"},{"key":"e_1_2_10_29_1","doi-asserted-by":"publisher","DOI":"10.1113\/JP287700"},{"issue":"8","key":"e_1_2_10_30_1","doi-asserted-by":"crossref","first-page":"1624","DOI":"10.1016\/j.burns.2017.04.003","article-title":"A review of the evidence for threshold of burn injury","volume":"43","author":"Martin N.","year":"2017","journal-title":"Burns: Journal of the International Society for Burn Injuries"},{"issue":"3","key":"e_1_2_10_31_1","doi-asserted-by":"crossref","DOI":"10.1002\/cph4.70017","article-title":"Influence of exercise heat acclimation protocol characteristics on adaptation kinetics: A quantitative review with Bayesian meta\u2010regressions","volume":"15","author":"McDonald P.","year":"2025","journal-title":"Comprehensive Physiology"},{"key":"e_1_2_10_32_1","unstructured":"NESO. (2026).Carbon intensity API.https:\/\/carbonintensity.org.uk"},{"key":"e_1_2_10_33_1","unstructured":"Ofgem. (2026).Energy price cap and standing charges explained.https:\/\/www.ofgem.gov.uk\/information\u2010consumers\/energy\u2010advice\u2010households\/energy\u2010price\u2010cap\u2010explained"},{"issue":"4","key":"e_1_2_10_34_1","doi-asserted-by":"crossref","first-page":"1873","DOI":"10.1152\/physrev.00038.2020","article-title":"Exercise under heat stress: Thermoregulation, hydration, performance implications and mitigation strategies","volume":"101","author":"P\u00e9riard J. D.","year":"2021","journal-title":"Physiological Reviews"},{"key":"e_1_2_10_35_1","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.autneu.2016.02.002","article-title":"Cardiovascular adaptations supporting human exercise\u2010heat acclimation","volume":"196","author":"P\u00e9riard J. D.","year":"2016","journal-title":"Autonomic Neuroscience"},{"key":"e_1_2_10_36_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.phrs.2024.107349","article-title":"Far\u2010infrared radiation and its therapeutic parameters: A superior alternative for future regenerative medicine?","volume":"208","author":"Qin B.","year":"2024","journal-title":"Pharmacological Research"},{"issue":"3","key":"e_1_2_10_37_1","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1152\/jappl.1964.19.3.531","article-title":"A new weighting system for mean surface temperature of the human body","volume":"19","author":"Ramanathan N.","year":"1964","journal-title":"Journal of Applied Physiology"},{"issue":"6","key":"e_1_2_10_38_1","doi-asserted-by":"crossref","first-page":"1628","DOI":"10.1152\/japplphysiol.00067.2025","article-title":"Muscle temperature increases during a single far infrared sauna session without changes in intestinal temperature","volume":"138","author":"Reed E. L.","year":"2025","journal-title":"Journal of Applied Physiology"},{"issue":"1","key":"e_1_2_10_39_1","doi-asserted-by":"crossref","DOI":"10.1002\/cph4.70089","article-title":"Heat therapy: Targeting health, disease, and Disability","volume":"16","author":"Richey R. E.","year":"2026","journal-title":"Comprehensive Physiology"},{"issue":"4","key":"e_1_2_10_40_1","doi-asserted-by":"crossref","first-page":"1883","DOI":"10.1002\/j.2040-4603.2011.tb00385.x","article-title":"Integrated physiological mechanisms of exercise performance, adaptation, and maladaptation to heat stress","volume":"1","author":"Sawka M. N.","year":"2011","journal-title":"Comprehensive Physiology"},{"issue":"11","key":"e_1_2_10_41_1","first-page":"1275","article-title":"Effects of exposure to Finnish sauna","volume":"12","author":"Sohar E.","year":"1976","journal-title":"Israel Journal of Medical Sciences"},{"issue":"4","key":"e_1_2_10_42_1","doi-asserted-by":"crossref","first-page":"785","DOI":"10.1007\/s00421-014-3060-1","article-title":"Effect of sauna\u2010based heat acclimation on plasma volume and heart rate variability","volume":"115","author":"Stanley J.","year":"2015","journal-title":"European Journal of Applied Physiology"},{"issue":"4","key":"e_1_2_10_43_1","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1007\/BF00417979","article-title":"Plasma volume during heat stress and exercise in women","volume":"57","author":"Stephenson L. A.","year":"1988","journal-title":"European Journal of Applied Physiology and Occupational Physiology"},{"key":"e_1_2_10_44_1","first-page":"255","article-title":"Far infrared radiation (FIR): Its biological effects and medical applications","volume":"4","author":"Vatansever F.","year":"2012","journal-title":"Photonics & Lasers in Medicine"},{"key":"e_1_2_10_45_1","first-page":"403","volume-title":"Nucleation\u00a0and\u00a0Atmospheric\u00a0Aerosols","author":"Vesala T.","year":"1996"},{"issue":"1","key":"e_1_2_10_46_1","article-title":"Cardiovascular and Thermal Response to Dry\u2010Sauna Exposure in Healthy Subjects","volume":"2014","author":"Zalewski P.","year":"2014","journal-title":"Physiology Journal"}],"container-title":["Experimental Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/EP094028","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/full-xml\/10.1113\/EP094028","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/EP094028","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T07:36:59Z","timestamp":1785483419000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/EP094028"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,31]]},"references-count":45,"alternative-id":["10.1113\/EP094028"],"URL":"https:\/\/doi.org\/10.1113\/ep094028","archive":["Portico"],"relation":{},"ISSN":["0958-0670","1469-445X"],"issn-type":[{"value":"0958-0670","type":"print"},{"value":"1469-445X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,31]]},"assertion":[{"value":"2026-05-12","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-07-13","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-07-31","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"EP094028"}}