Daiwa House Industry and Nara Medical University Commence Joint Research on "Living Environments for Achieving Good Quality Sleep" (Newsletter)

Daiwa House Industry Co., Ltd. (Headquarters: Osaka City, President: Hirotsugu Otomo, hereinafter "Daiwa House Industry") and Nara Medical University (President: Midori Shima, hereinafter "Nara Medical University") began a joint research project on living environments for achieving good quality sleep on April 1, 2026.

In this study, the impact of the living environment on sleep will be medically verified through a randomized controlled trial (*1) involving approximately 200 adults. Daiwa House Industry aims to realize a "living environment that enhances sleep quality" based on medical evidence by integrating the findings of this study with technologies related to high insulation, whole-house air conditioning, and soundproofing/silencing.

*1. A clinical research method that compares results by randomly assigning subjects to groups with or without the intervention of research elements. It is internationally recognized as a highly reliable method for medical evidence.

Ensuring good quality sleep is essential for maintaining and promoting health. While the Ministry of Health, Labour and Welfare's "Sleep Guidelines for Health Promotion 2023" recommends adults get six or more hours of sleep, the proportion of people with an average daily sleep time of less than six hours is over 40% for men in their 30s to 50s and women in their 40s to 50s, making securing adequate sleep for every citizen a significant health issue.

Previous medical research has shown that the sleep environment, including temperature, light, and sound, is also involved in sleep quality, and the same guidelines recommend adjusting the sleep environment appropriately to obtain good quality sleep. However, medical knowledge regarding the optimal living environment for sleep cannot be said to be sufficiently accumulated. In particular, there are only a handful of reliable studies based on Japan's climatic conditions and actual living environments. In the housing industry as well, efforts have mostly been limited to referencing findings from prior research, and there has not been enough initiative to verify housing conditions suitable for health based on a medical framework and apply it to home building.

Therefore, Daiwa House Industry and Nara Medical University have decided to start joint research aiming to develop housing products based on new medical evidence concerning good quality sleep. They will explore how to create housing that allows even those who find it difficult to secure sufficient sleep time due to work or family circumstances to achieve healthy, high-quality sleep by arranging the living environment without drastically changing their lifestyle.

Going forward, both parties will continue to contribute to the realization of an affluent residential life and sustainable social development by advancing research on homes where people can live healthily.

1. Overview of Joint Research
This research will be conducted jointly by the Daiwa House Industry Comprehensive Technical Research Institute and Professor Keigo Saeki of Nara Medical University. Based on Japan's climatic and actual living environments, it aims to medically verify the effects of environmental factors such as temperature, humidity, illuminance, and sound on sleep and health, and to obtain new evidence that contributes to good quality sleep.

Period: April 1, 2026 - March 31, 2029