Relationship between cerebral blood flow and cognitive decline in the elderly with heat stress

• Project/Area Number: 17K01656
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Developmental mechanisms and the body works
• Research Institution: Osaka Electro-Communication University
• Principal Investigator: OTA Akemi 大阪電気通信大学, 医療健康科学部, 教授 (70360732)
• Co-Investigator(Kenkyū-buntansha): 岡崎 和伸 大阪公立大学, 都市健康・スポーツ研究センター, 教授 (70447754)
• Project Period (FY): 2017-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 暑熱ストレス / 加齢 / 認知機能 / 脳血流 / 事象関連電位 / 脳血流速度 / 暑熱 / 暑熱負荷 / 姿勢ストレス

Outline of Final Research Achievements

Heat environment and postural change from supine to sitting position decrease cerebral blood flow. Since the circulatory response is attenuated in the elderly, the combination of heat and postural stress is likely to result in a significant decrease in resting cerebral blood flow, even when each is a mild load. The decrease in resting cerebral blood flow suppresses the increase in cerebral blood flow during cognitive activity. In this study, we examined the effects of aging on cognitive function and cerebral blood flow under heat stress. The results suggested that cognitive processing functions may decrease with aging, although no effect of aging on the reaction time to sound stimuli.

Academic Significance and Societal Importance of the Research Achievements

高齢者は若年者と比較して熱中症を発症しやすく、暑熱環境下においては、めまいや失神の発生が高くなる。暑熱環境下でも認知機能を維持し、正しい判断や行動を可能にすることは重要である。また、今後ますます高齢者が増加し、暑熱環境下で働く高齢労働者も増えると予測される。本研究では、暑熱環境下で音に対する反応時間が増悪していなくても、高齢者では認知処理機能が減弱している可能性があることを示唆した。これらの結果は、暑熱環境下で高齢者に生じる事故防止に役立つ基礎データとなる。

Research Products

• [Journal Article] The effects of aging on the distribution of cerebral blood flow with postural changes and mild hyperthermia (2019)
  • Author(s): Ota Akemi、Takeda Ryosuke、Imai Daiki、Naghavi Nooshin、Kawai Eriko、Saho Kosuke、Morita Emiko、Suzuki Yuta、Yokoyama Hisayo、Miyagawa Toshiaki、Okazaki Kazunobu
  • Journal Title: European Journal of Applied Physiology Volume: 119 Issue: 5 Pages: 1261-1272
  • DOI: 10.1007/s00421-019-04118-5
  • NAID: 120006849936
  • Peer Reviewed
• [Presentation] Takeda R,Imai D,Kawai E,Ota A,Saho K,Morita E,Suzuki Y,Yokoyama H,Takahashi H,Hayashi H,Kimura T,Okazaki K (2019)
  • Author(s): Heat acclimation program for firefighters reduced heat stress and improved thermal sensation and thermal comfort during exercise wearing with a firefighting suit.
  • Organizer: Experimental Biology 2019
  • Int'l Joint Research
• [Presentation] The effect of aging on event-related potentials during mild-hyperthermia. (2019)
  • Author(s): Ota Akemi, Takeda Ryosuke, Imai Daiki, Kawai Eriko, Saho Kosuke, Morita Emiko, Suzuki Yuta, Yokoyama Hisayo, Okazaki Kazunobu
  • Organizer: The Journal of Physiological Sciences
  • Int'l Joint Research
• [Presentation] The Effect of Mild Heat Stress on Event-Related Potential in the Elderly (2019)
  • Author(s): Akemi Ota, Ryosuke Takeda, Daiki Imai, Eriko Kawai, Kosuke Saho, Emiko Morita, Yuta Suzuki, Hisayo Yokoyama, and Kazunobu Okazaki
  • Organizer: Experimental Biology 2019
  • Int'l Joint Research
• [Presentation] 受動加温による軽度高体温が認知課題中の脳血流応答に及ぼす影響 (2018)
  • Author(s): 太田暁美、 竹田良祐、 今井大喜、 河合英理子、 佐保光祐、森田恵美子、鈴木雄太、 横山久代、 岡﨑和伸
  • Organizer: 第73回日本体力医学会大会
• [Presentation] The effect of aging on event-related potentials during mild-hyperthermia (2018)
  • Author(s): Akemi Ota, Ryosuke Takeda, Daiki Imai, Eriko Kawai, Kosuke Saho, Emiko Morita, Yuta Suzuki, Hisayo Yokoyama, and Kazunobu Okazaki
  • Organizer: 9th Federation of the Asian and Oceanian Physiological Societies Congress
  • Int'l Joint Research
• [Presentation] A 3-month walking training does not improve thermal sensation in healthy elderly men (2018)
  • Author(s): Ryosuke Takeda, Daiki Imai, Akemi Ota, Nooshin Naghavi, Eriko Kawai, Genta Hanno, Emiko Morita, Yuta Suzuki, Hisayo Yokoyama, Kazunobu Okazaki
  • Organizer: 第95回日本生理学会大会
• [Presentation] 定期的運動の実施が高齢者の温度感覚に及ぼす影響 (2017)
  • Author(s): 竹田良祐，今井大喜，太田暁美，河合英理子，半野源太，Nagavi Nooshin，森田恵美子，鈴木雄太，横山久代，岡崎和伸
  • Organizer: 第72回日本体力医学会大会
• [Presentation] Ryosuke Takeda, Daiki Imai, Akemi Ota, Eriko Kawai, Genta Hanno, Nooshin Naghavi, Emiko Morita, Yuta Suzuki, Hisayo Yokoyama, Kazunobu Okazaki (2017)
  • Author(s): Whole body and skin thermal sensation are not improved with regular exercise in elderly men
  • Organizer: The 17th International Conference On Environmental Ergonomics
  • Int'l Joint Research