{
  "abstract": "This study examined gastrointestinal temperature (T GI ) during and body mass (BM) changes pre/post the Western States Endurance Run 100 (WSER), a 100‐mile ultramarathon in hot conditions. Thirty‐nine participants ingested a telemetric pill 30–90 min before the WSER start, and BM was measured pre‐ and post‐race. Environmental conditions were recorded every 30 min at 15 locations along the course. In‐race T GI data were obtained from 23 finishers (54%; 7 females; 42 ± 11 years), including 2 podium finishers and an additional top‐10 finisher. Participants finished in 14–18 h ( n = 4), 19–25 h ( n = 6), and 26–30 h ( n = 13). Peak T GI averaged 38.90°C ± 0.55°C (range 37.76°C–40.09°C) with 9 runners exceeding 39°C and 2 exceeding 40°C. Faster finish times were associated with higher peak T GI ( r = −0.57, p = 0.004). Seven runners (30%) reached peak T GI in the final 2% of the race. Mean BM change was −1.8% ± 3.1% (range −7.4% to +6.4%), with no associations observed between BM change and peak T GI or finish time. Ambient temperature ranged 5°C–39.6°C and was associated with higher T GI ( r = 0.80, p = 0.008). Despite ambient temperatures approaching 40°C, T GI >40°C were rare and transient. Faster runners experienced greater thermal strain, likely reflecting higher metabolic heat production and exposure to the hottest course segments. Hyperthermia risk may be highest near the race finish and during the most demanding segments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 11,
  "authors": [
    {
      "name": "Loïs Mougin"
    },
    {
      "name": "Richard Stennett"
    },
    {
      "name": "Brett Ely"
    },
    {
      "name": "Baptiste Morel"
    },
    {
      "name": "Larry O'Neill"
    },
    {
      "name": "Chris Esh"
    },
    {
      "name": "William Adams"
    },
    {
      "name": "Daniel Longman"
    },
    {
      "name": "Richard Blagrove"
    },
    {
      "name": "Lee Taylor"
    },
    {
      "name": "Stephen Mears"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5m80n12ce45vw.bib",
  "cited_by": 0,
  "doi": "10.14814/phy2.71089",
  "fulltext_url": null,
  "id": "5m80n12ce45vw",
  "issns": [
    "2051-817X"
  ],
  "landing_url": "https://hal.science/hal-05747001v1",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdv"
    ],
    [
      "hal",
      "1.sdv.mhep"
    ],
    [
      "hal",
      "2.sdv.mhep.phy"
    ],
    [
      "openalex",
      "2737|Thermoregulation and physiological responses"
    ]
  ],
  "openalex": "W7211877484",
  "pdf_url": "https://onlinelibrary.wiley.com/doi/pdfdirect/10.14814/phy2.71089",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-07",
  "publisher": "Wiley",
  "ris": "https://research.draconitic.com/paper/5m80n12ce45vw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:33Z",
      "native_id": "hal-05747001",
      "source": "hal",
      "url": "https://hal.science/hal-05747001v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "hal:0.sdv",
      "subfield": "general"
    },
    {
      "field": "medicine",
      "origin": "hal:2.sdv.mhep.phy",
      "subfield": "physiology"
    }
  ],
  "title": "Gastrointestinal temperature of elite and recreational adult runners during a 100‐mile ultramarathon under heat exposure",
  "title_text": "Gastrointestinal temperature of elite and recreational adult runners during a 100‐mile ultramarathon under heat exposure",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:33Z",
  "url": "https://research.draconitic.com/paper/5m80n12ce45vw",
  "venue": "Physiological Reports",
  "versions": []
}