As global warming accelerates, the relationship between heat exposure and human health—particularly the concept of heat acclimatization—has become an urgent issue. Extreme heat is increasingly recognized as a significant health risk in both environmental and occupational settings. Not only is it a leading cause of weather-related mortality, but it also exacerbates pre-existing health conditions.

According to the Lancet Countdown 2023 report—a global research collaboration on climate change and health led by the medical journal The Lancet—people experienced an annual average of 86 days of health-threatening high temperatures between 2018 and 2022. In response to the health impacts of climate change, key international organizations such as the World Health Organization (WHO) have launched initiatives including the Alliance for Transformative Action on Climate and Health (ATACH) and the Global Heat Health Information Network (GHHIN). These efforts aim to advance urgent responses and share strategies and knowledge to mitigate the health risks of extreme heat.

In Japan, the heatwave of 2024 resulted in 97,578 emergency medical transports and 2,033 deaths. The number of heat-related deaths that year far exceeded those caused by other natural disasters such as earthquakes, floods, or landslides. Moreover, societal factors such as demographic aging, changing household composition, and the increasing number of single-person households are compounding the risks associated with heatstroke. By 2040, people aged 65 and over are projected to account for 35.3% of Japan’s total population (up from 12% in 1990). Consequently, the incidence of heatstroke is expected to rise significantly. In Tokyo alone, the number of heatstroke cases is projected to increase by 360% by 2040 due to population growth and aging.

To address the increasing risk of heatstroke anticipated in the coming years, Japan officially launched the Heat Stroke Alert System in 2021. More recently, as of June 1, 2025, workplace heatstroke prevention measures have become mandatory. Furthermore, the Heat Illness Prevention Action Plan approved by the Cabinet on May 30, 2023, outlines a goal of halving heatstroke-related deaths by 2030. This plan includes initiatives to raise public awareness, provide timely information, implement preventive measures for vulnerable populations such as older adults and children, promote collaboration with industry, and advance research related to heatstroke.

Against this backdrop, the upcoming HGPI Seminar will welcome Dr. Shoji Yokobori, Professor and Director and Chair of Department of Emergency and Critical Care Medicine, Nippon Medical School and Graduate School of Nippon Medical School. A leading expert in the field of heat-related illnesses and emergency medicine, Dr. Yokobori is actively addressing the lack of comprehensive data on the scale of health impacts from heat-related illnesses. His work focuses on identifying the most vulnerable populations, assessing preemptive strategies, and developing practical tools that can support both healthcare professionals and the general public. As the health risks posed by heatwaves continue to grow, this seminar aims to deepen our understanding of the importance of evidence-based preparedness and policy responses.

[Event Overview]

• Speaker:
  Dr. Shoji Yokobori (Professor, Director and Chair of Department of Emergency and Critical Care Medicine, Nippon Medical School and Graduate School of Nippon Medical School)
• Date & Time: Tuesday, July 1, 14:30-15:45 JST
• Format: Online (Zoom webinar)
• Language: Japanese
• Participation Fee: Free
• Capacity: 500 participants

■Profile:

Shoji Yokobori (Professor, Director and Chair of Department of Emergency and Critical Care Medicine, Nippon Medical School and Graduate School of Nippon Medical School)

Prof. Yokobori graduated from Gunma University of Medicine in 1999 and obtained his Ph.D from Graduate School of Nippon Medical School in 2005. From 2010 to 2013, he had carried out research on neurotrauma as a visiting researcher at University of Miami Miller School of Medicine in the United States. His specialty is neruosurgical emergency. He is currently engaged in clinical work and research on basic experiment of nerve regeneration, transplantation of stem cells, brain hypothermia and heatstroke.