Otsuka Pharmaceutical Co., Ltd. (Otsuka) has announced joint research with World Athletics and Waseda University in the World Athletics Championships Tokyo 25 (WCH Tokyo 25) as a global partner of the WCH Tokyo 25. The joint research will focus on investigating the endurance of the athletes' knowledge and practice regarding heat acclimatization and fluid/nutrition intake pre and during the competition. In addition to its current expertise and findings, Otsuka will support athletes new insights gained from this joint research to improve their safety and performance in exercise and sports.

With the growing impact of global warming, the importance of heat preparation in outdoor sports during summer has become increasingly recognized. In addition to heat acclimatization/acclimation, strategies on fluid, electrolyte, and nutritional intake, body cooling, and conditioning such as infection prevention are essential for athletes to maintain their performance.

We expect blazing hot and humid weather during the WCH Tokyo 25 this September. National team athletes from each country and region are required to prepare for extreme heat to ensure they perform at their best. To address this, the research will conduct a survey on athletes' knowledge and practices of heat preparation, as well as fluid and nutrition intake. It will also explore the relationship between these factors and their performance during the competition. Based on the findings from this research, Otsuka's aim is not only to explore effective approaches to sports in hot environments but also to provide practical insights for future generations of athletes and people involved in sports around the world.

●Research Title： Endurance Athletes' Knowledge & Practices in Nutrition and Heat Acclimation/Acclimatization

●Research Duration： September 13th, 2025 to March, 2026 (planned)

●Research Methods：　

This study aims to investigate elite endurance athletes' knowledge, performance preparation, and race-day conduct regarding heat acclimatization and hydration/nutrition strategies, targeting male and female athletes competing in the marathon and race walk events (20 km, 35 km) at the WCH Tokyo 25. Pre- and post-race body weight measurements will be conducted in the designated research area prepared by World Athletics at the competition venue on the race day. Based on the bodyweight measurements, the dehydration level (in % of body mass loss) and estimated total body sweat loss will be calculated.

Otsuka will also support the international conference "Global Summit on Athletics Science & Medicine" organized by the World Academy for Endurance Medicine on September 19. At the summit, Otsuka will share research findings and insights on electrolyte beverages accumulated to date. Through these initiatives, Otsuka aims to provide valuable information to athletes and professionals involved in exercise and sports around the world.

Based on the corporate philosophy of 'Otsuka-people creating new products for better health worldwide,' Otsuka Pharmaceutical continues to contribute to the health and well-being of people around the world.

■The World Athletics Championships Tokyo 25　

https://worldathletics.org/competitions/world-athletics-championships/tokyo25

・Organizer：World Athletics

・Period：Saturday, September 13th to Sunday, September 21st, 2025 (9 days)

・Venue：Japan National Stadium (marathon and race walking will be held within Tokyo)

・Athletes：more than 2,000 (planned)

・Participating countries and regions：approximately 200 (planned)

・Events：49 events

Reference: Research & Development focused on exercise and nutrition

In 1984, Otsuka Pharmaceuticals established Nutraceuticals Research Institute in Saga prefecture, as Japan's first private clinical exercise and nutrition research facility. Here we've conducted a various study and developed products with innovative ideas and have demonstrated their effectiveness across various situations. These innovative and scientific-based products include an electrolyte beverage designed for rapid hydration, a functional drink which was developed based on the discovery of the importance of dietary fiber, which at that time was not considered to be an essential part of a healthy diet, a sports drink that supports the body's energy supply during sustained exercise, a protein jelly designed for the reliable, well-timed and efficient intake of protein, and drinks that can provide BCAA which is essential for endurance sports.

Now Otsuka has been reorganized into the "Nutraceuticals Research Institute" (Saga Site / Otsu Site) . Otsuka also collaborates with universities and external research institutions, publishing data and continuously creating new scientific value. Through these efforts, Otsuka actively shares information to contribute to people's health.

■Ion supply drink research on replenishment of fluid and electrolytes

https://www.otsuka.co.jp/en/nutraceutical/about/rehydration/researchlab/

Otsuka has begun overseas expansion with an electrolyte drink and continued to study the impact of fluid and electrolytes replenishment on the body. These efforts have uncovered scientific evidence supporting the drink's usefulness not only during perspiration from sports or labor in hot conditions but also in everyday situations, such as during dry winter months or after bathing. 40 years since then, Otsuka has continued its research and accumulated scientific evidence demonstrating its effectiveness. The company also has run awareness campaigns focused on the importance of replenishing water and electrolytes in various situations throughout the year. This includes information on how to prevent heat stroke in hot environments, as well as ways to rehydrate in dry seasons such as fall and winter.

●Representative research titles：

・The effect of ingestion of electrolyte-sugar drink on recovery of dehydration

・Effects of hydration on fluid balance and lower-extremity blood viscosity during long airplane flights

・Changes in plasma volume and blood viscosity during a 4-hour period sitting in a dry environment: The effects of prehydration

・Rehydration after bathing: Comparison between a carbohydrate-electrolyte beverage and water

・Effect of prehydration on nasal mucociliary clearance in low relative humidity

・Enhanced renal Na⁺ reabsorption by carbohydrates in beverages during restitution from thermal and exercise-induced dehydration in men

About Otsuka

Otsuka Pharmaceutical Co., Ltd. is a total healthcare company that focuses on each individual's potential to enhance their well-being. Our medical-related business provides treatments and diagnostics for both physical and mental health. Our nutraceutical business supports daily health maintenance and improvement. Otsuka's unique products and services are based on scientific evidence, under the guidance of our corporate philosophy: Otsuka-people creating new products for better health worldwide.

For further information, please visit. www.otsuka.co.jp/en/