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Effect of time-of-day on heat-induced hyperventilation and cerebral hypoperfusion

Research Project

Project/Area Number 18K17858
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 59020:Sports sciences-related
Research InstitutionPrefectural University of Hiroshima

Principal Investigator

Tsuji Bun  県立広島大学, 大学教育実践センター, 准教授 (40707212)

Project Period (FY) 2018-04-01 – 2020-03-31
Project Status Completed (Fiscal Year 2019)
Budget Amount *help
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Keywords高体温 / 過換気 / 熱中症 / 脳虚血 / 時刻 / 暑熱順化
Outline of Final Research Achievements

Hyperthermia leads to increases in minute ventilation, resulting in hypocapnia and cerebral hypoperfusion. This study examined the effect of time-of-day on cerebrovascular responsiveness to changes in end-tidal CO2 during passive heating. We showed that cerebral vasodilator response to CO2 during heat stress diminishes in the evening than in the morning, and that exercise training in the heat (heat acclimation) at a fixed daily time does not affect cerebrovascular responsiveness to CO2 during passive heating.

Academic Significance and Societal Importance of the Research Achievements

近年,体温上昇時に起こる過換気とそれに付随する脳血流の低下が熱中症の一因であることが示唆されているが,これら反応に及ぼす時刻の影響はほとんど明らかではなかった。本研究の結果,早朝よりも夕方では高体温時の脳血管拡張機能が低下することが明らかになった。熱中症による搬送者数は早朝よりも昼から夕方で多く,これには単に気温の変化だけでなく,本研究で観察された夕方における二酸化炭素に対する脳血管拡張機能の低下といった高体温時の脳血流反応の日内変化が関与している可能性がある。本結果は暑熱環境下おける安全確保とその具体策を提示する上で重要な基礎的知見になると考えられる。

Report

(3 results)
  • 2019 Annual Research Report   Final Research Report ( PDF )
  • 2018 Research-status Report
  • Research Products

    (1 results)

All 2019

All Presentation (1 results) (of which Int'l Joint Research: 1 results)

  • [Presentation] Effect of time-of-day on cerebral CO2 reactivity in resting heated humans2019

    • Author(s)
      Bun Tsuji, Saori Yamashita, Mika Yamamoto, Naoto Fujii, Takeshi Nishiyasu
    • Organizer
      ARIHHP Human High Performance International Forum 2019
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research

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Published: 2018-04-23   Modified: 2021-02-19  

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