{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T05:02:36Z","timestamp":1782882156001,"version":"3.54.5"},"reference-count":33,"publisher":"BMJ","issue":"17","funder":[{"name":"Joint Medical Committee of IOC, FINA, ITU"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["Br J Sports Med"],"accepted":{"date-parts":[[2019,1,28]]},"published-print":{"date-parts":[[2019,9]]},"abstract":"<jats:sec>\n                  <jats:title>Objectives<\/jats:title>\n                  <jats:p>To provide a rationale for minimum water temperature rules for elite and subelite marathon swim racing and highlight factors that make individuals vulnerable to excessive cooling during open water swimming.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>12 lean competitive swimmers swam for up to 2\u2009hours, three times in different water temperatures between 14\u00b0C and 20\u00b0C, wearing standard swimming costumes and hats. Rectal temperature (T<jats:sub>re<\/jats:sub>), oxygen consumption, perception of cold and performance were measured.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>In 16\u00b0C, half the swimmers did not complete a 2-hour swim; four became (or were predicted to become) hypothermic within 2\u2009hours. In 18\u00b0C, three-quarters completed the swim; three became (or were predicted to become) hypothermic. In 20\u00b0C, one swimmer was predicted to become hypothermic in under 2\u2009hours. The mean linear rate of fall of T<jats:sub>re<\/jats:sub> was greater in 16\u00b0C (\u22121.57\u00b0C\/hour) than 18\u00b0C (\u22121.07\u00b0C\/hour) (p=0.03). There was no change in swimming performance during the swims or between conditions. Most of the cooling rate could be explained by metabolic heat production and morphology for both 16\u00b0C (R<jats:sup>2<\/jats:sup>=0.94, p&lt;0.01) and 18\u00b0C (R<jats:sup>2<\/jats:sup>=0.82, p&lt;0.01) conditions. No relationship was observed between T<jats:sub>re<\/jats:sub> and perception of thermal sensation (r=0.25, p=0.13), and there was a weak correlation between T<jats:sub>re<\/jats:sub> and thermal comfort (r=0.32, p=0.04).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>We recommend that 16\u00b0C and 18\u00b0C water are too cold for elite marathon swim racing. F\u00e9d\u00e9rationInternationale de Natation rules were changed in 2017 to make wetsuits compulsory below 18\u00b0C and optional below 20\u00b0C.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1136\/bjsports-2018-099978","type":"journal-article","created":{"date-parts":[[2019,3,1]],"date-time":"2019-03-01T17:25:35Z","timestamp":1551461135000},"page":"1078-1084","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":31,"title":["How cold is too cold? Establishing the minimum water temperature limits for marathon swim racing"],"prefix":"10.1136","volume":"53","author":[{"given":"Jane","family":"Saycell","sequence":"first","affiliation":[{"name":"Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mitch","family":"Lomax","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heather","family":"Massey","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mike","family":"Tipton","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2019,3,1]]},"reference":[{"key":"2025080113215145000_53.17.1078.1","doi-asserted-by":"crossref","first-page":"2012","DOI":"10.1249\/01.mss.0000241641.75101.64","article-title":"American College of Sports Medicine position stand: prevention of cold injuries during exercise","volume":"38","author":"Castellani","year":"2006","journal-title":"Med Sci Sports Exerc"},{"key":"2025080113215145000_53.17.1078.2","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(99)07273-6"},{"key":"2025080113215145000_53.17.1078.3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/2046-7648-3-12","article-title":"Moving in extreme environments: open water swimming in cold and warm water","volume":"3","author":"Tipton","year":"2014","journal-title":"Extrem Physiol Med"},{"key":"2025080113215145000_53.17.1078.4","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1186\/2046-7648-1-8","article-title":"Changes in body core and body surface temperatures during prolonged swimming in water of 10\u00b0C-a case report","volume":"1","author":"R\u00fcst","year":"2012","journal-title":"Extrem Physiol Med"},{"key":"2025080113215145000_53.17.1078.5","unstructured":"FINA. 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