{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T19:44:25Z","timestamp":1772999065310,"version":"3.50.1"},"reference-count":35,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T00:00:00Z","timestamp":1772582400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T00:00:00Z","timestamp":1772582400000},"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":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    We examined whether seven consecutive days of warm\u2010water immersion could elevate resting and exercise\u2010induced levels of brain\u2010derived neurotrophic factor (BDNF), irisin and klotho in older adults. These biomarkers support cognitive and metabolic health, but their levels decline with age. Passive heat exposure, like warm\u2010water immersion, may offer a promising alternative to exercise for enhancing cellular\u2010level\u00a0physiological resilience in populations where exercise is limited. Twelve habitually active older men (median [IQR] age: 68 [64\u201373] years; : 34.1 [29.4\u201336.1] mL O\n                    <jats:sub>2<\/jats:sub>\n                    \u0387\u00a0kg\n                    <jats:sup>\u2212<\/jats:sup>\n                    <jats:sup>1<\/jats:sup>\n                    \u00a0\u0387 min\n                    <jats:sup>\u2212<\/jats:sup>\n                    <jats:sup>1<\/jats:sup>\n                    ) completed seven consecutive days of \u223c90\u2010min warm\u2010water immersion (\u223c40\u00b0C), with rectal temperature maintained at \u223c38.5\u00b0C for the final 60\u00a0min. Before and after the warm\u2010water immersion intervention, participants completed a standardized exercise\u2013heat stress test consisting of three 30\u2010min cycling bouts (150, 200 and 250\u00a0W \u0387\u00a0m\n                    <jats:sup>\u2212<\/jats:sup>\n                    <jats:sup>2<\/jats:sup>\n                    ), each separated by 15\u2010min rest. Blood samples were collected at baseline and post\u2010exercise to assess circulating BDNF, irisin, and klotho. Repeated warm\u2010water immersion increased resting BDNF by 2.43\u00a0ng \u0387\u00a0mL\n                    <jats:sup>\u22121<\/jats:sup>\n                    (95% CI: 0.64\u20134.23;\n                    <jats:italic>P<\/jats:italic>\n                    \u00a0=\u00a00.005; 1.73\u2010fold) and irisin by 0.94\u00a0ng \u0387\u00a0mL\n                    <jats:sup>\u22121<\/jats:sup>\n                    (95% CI: 0.25\u20131.63;\n                    <jats:italic>P<\/jats:italic>\n                    \u00a0=\u00a00.005; 1.65\u2010fold). Resting klotho concentration did not change (mean difference: +0.05\u00a0ng \u0387\u00a0mL\n                    <jats:sup>\u22121<\/jats:sup>\n                    ; 95% CI: \u20130.05 to 0.14;\n                    <jats:italic>P<\/jats:italic>\n                    \u00a0=\u00a00.539). No significant exercise\u2010induced changes in any cytoprotective hormones were observed (\n                    <jats:italic>P<\/jats:italic>\n                    \u2265 0.053). Seven consecutive days of warm\u2010water immersion elevated resting levels of BDNF and irisin, but not klotho, in older males. Passive heat acclimation may offer a non\u2010exercise strategy to upregulate biomarkers linked to cognitive and metabolic health, reflecting activation of cellular pathways associated with physiological resilience.\n                  <\/jats:p>","DOI":"10.1113\/ep093317","type":"journal-article","created":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T17:03:10Z","timestamp":1772989390000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Seven days of warm\u2010water immersion enhances resting irisin and BDNF, but not klotho, in older men"],"prefix":"10.1113","author":[{"given":"Joel M","family":"Garrett","sequence":"first","affiliation":[{"name":"School of Allied Health, Sport and Social Work Griffith University  Queensland Australia"},{"name":"Australian Centre for Precision Health and Technology (PRECISE) Griffith University  Gold Coast Queensland Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"James J","family":"McCormick","sequence":"additional","affiliation":[{"name":"Human and Environmental Physiology Research Unit, School of Human Kinetics University of Ottawa  Ottawa Ontario Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kelli E","family":"King","sequence":"additional","affiliation":[{"name":"Human and Environmental Physiology Research Unit, School of Human Kinetics University of Ottawa  Ottawa Ontario Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kristina\u2010Marie T","family":"Janetos","sequence":"additional","affiliation":[{"name":"Human and Environmental Physiology Research Unit, School of Human Kinetics University of Ottawa  Ottawa Ontario Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nathalie V","family":"Kirby","sequence":"additional","affiliation":[{"name":"Human and Environmental Physiology Research Unit, School of Human Kinetics University of Ottawa  Ottawa Ontario Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9509-7682","authenticated-orcid":false,"given":"Fergus K","family":"O'Connor","sequence":"additional","affiliation":[{"name":"School of Allied Health, Sport and Social Work Griffith University  Queensland Australia"},{"name":"Australian Centre for Precision Health and Technology (PRECISE) Griffith University  Gold Coast Queensland Australia"},{"name":"Human and Environmental Physiology Research Unit, School of Human Kinetics University of Ottawa  Ottawa Ontario Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8683-6973","authenticated-orcid":false,"given":"Glen P","family":"Kenny","sequence":"additional","affiliation":[{"name":"Australian Centre for Precision Health and Technology (PRECISE) Griffith University  Gold Coast Queensland Australia"},{"name":"Clinical Epidemiology Program Ottawa Hospital Research Institute  Ottawa Ontario Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2026,3,4]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41422-024-01064-6"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11332-024-01244-2"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1974.37.2.247"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.cger.2020.06.009"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1093\/gerona\/glu057"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1111\/jnc.15707"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jtherbio.2019.102482"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jtherbio.2021.103067"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.neurobiolaging.2004.01.003"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0000000000003649"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.3389\/fnagi.2021.649929"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.12965\/jer.2550074.037"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/j.2040-4603.2013.tb00536.x"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-023-05171-x"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.2174\/1874609815666220304200939"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.1139\/apnm-2024-0289"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1196\/annals.1403.009"},{"key":"e_1_2_9_19_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.npep.2019.101961"},{"key":"e_1_2_9_20_1","first-page":"121","article-title":"Role of brain\u2010derived neurotrophic factor and NF\u2010\u03baB in neuronal plasticity and survival: From genes to phenotype","volume":"22","author":"Marini A. 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