[Feature: Rethinking Japan's Living Environment] Shintaro Ando: Considering Community and Housing from a Health Perspective

2021/12/06

There is a famous ethnic joke known as the "Titanic Joke." The gist is as follows.

──There are passengers reluctant to jump from a sinking luxury liner. The method of persuading these passengers differs by country, but the effective way to persuade a Japanese person is to say, "Everyone else has already jumped in."──

This passage is a piece of dark humor mocking the collectivist aspect of Japanese people. The common theory that Japanese people are more collectivist compared to Westerners has long been proven to be an illusion*1, and while the claim that only Japanese people are collectivist is a label, it cannot be denied that people's actions are influenced by the surrounding group.

As an illustration of this, there is a research study that examined environmental factors contributing to walking among approximately 4,000 elderly residents in Fujisawa City, Kanagawa Prefecture. This study categorized walking into walking for daily life and walking for health promotion, finding corresponding factors for each. It showed that "seeing others exercising in the neighborhood" and "having good neighborhood scenery" encouraged residents to walk. These results suggest that the community, which encompasses the surrounding group and the built environment, may influence individual health-promoting behaviors. This is considered to provide a hint for extending the healthy life expectancy of the nation.

The relationship between physical activity, including walking, and health has been demonstrated by numerous studies. Regular physical activity is said to play an important role in maintaining and promoting health, such as preventing heart disease, stroke, diabetes, hypertension, and obesity, as well as improving mental health. A lack of physical activity is seen in every country, with many people worldwide not meeting sufficient activity levels; in Japan, it is shown that one in three people lacks exercise.

In Japan, national health promotion projects are being conducted to solve issues related to lifestyle-related diseases. From fiscal year 2013, "Health Japan 21 (the second term)" was launched as the second phase, aiming to extend healthy life expectancy and improve dietary habits and exercise habits, with target values set for each department. In the physical activity and exercise-related departments, there was a shift from the evaluation values of motivation and drive used up to the first phase, to an emphasis on behavioral indicators such as "increasing the number of steps in daily life" and "increasing the percentage of people with exercise habits." Table 1 shows these target values and the interim evaluation values as of fiscal year 2016. Looking first at the number of steps, the baseline values as of 2010 were 7,841 steps for men and 6,883 steps for women, falling short of the Health Japan 21 (the first term) targets. Looking at the 2016 interim evaluation values, far from reaching the targets, the values have slightly worsened compared to the 2010 figures over these six years. The same trend is seen in the percentage of people with exercise habits. While the impact of an aging population is likely a factor, from a critical perspective, it could be said that previous efforts related to physical activity and exercise have continued to fail.

As described, no improvement was seen in the increase of daily steps or the percentage of people with exercise habits. Therefore, the interim report mentions that to achieve future goals, an approach to the living environment is more important than an individual approach through health guidance, and it is necessary to promote the creation of environments that make people walk without being consciously aware of it.

This brings to mind the results of the Fujisawa City study mentioned earlier. If seeing people exercising in the neighborhood contributes to increased walking, then we should develop walking routes with excellent scenery to create a trend of people walking. If improving scenery through flowerbed maintenance promotes going out, and if people participating in community activities become healthy, then flowerbed creation along walking routes should be positioned as a community activity. By forming a community that involves the entire group in such a virtuous cycle, we can persuade them by saying, "Everyone else has already jumped in (to the trend of zero-phase prevention)."

It is said that there are three phases in disease prevention. First, there is primary prevention. This aims to prevent the onset of disease through improvements in lifestyle habits. Next, secondary prevention aims for early detection and early treatment of diseases through health checkups, and tertiary prevention aims to prevent worsening or aftereffects after the onset of disease. While primary prevention has been pursued enthusiastically in Health Japan 21, measures for "Zero-Phase Prevention" are becoming more emphasized. As the word zero suggests, this refers to prevention at a stage prior to primary prevention. It aims to "prevent the occurrence of socio-economic, environmental, and behavioral conditions that cause undesirable lifestyle habits," referring to efforts that lead to health unconsciously without depending on individual effort.

In the previous section, I discussed zero-phase prevention from the community, but it is thought that zero-phase prevention can similarly be achieved from the home. In the Ministry of Land, Infrastructure, Transport and Tourism's Smart Wellness Housing Promotion Project, evidence is being accumulated regarding the reality of exposure to cold temperatures below 10°C—far below the recommended 18°C—inside Japanese homes, and the health hazards associated with cold exposure*2. For example, being cold upon waking leads to increased blood pressure; a cold living room before bed leads to nocturia and worsened sleep quality; and people who use kotatsu (heated tables) tend to sit for longer periods, reducing their physical activity. Eliminating such undesirable heating behaviors and cold exposure conditions can be considered zero-phase prevention that leads residents to health and longevity without them even realizing it.

As described above, there are many hidden factors in homes and communities that contribute to extending healthy life expectancy, and by controlling these well, it may be possible to link them to zero-phase prevention. However, it has also become clear that there are barriers preventing this promotion. When conducting a room temperature survey in a certain mountainous area, there was a respondent who said, "I don't feel cold at all at night," despite spending time in an environment below 5°C at night. Upon interviewing them, they said, "I've lived in this house forever, so this is normal." There were many similar responses, highlighting the deep-rooted nature of the problem.

To consider countermeasures for this social issue, a project titled "Creation of Housing and Communities that Realize Health and Longevity (Lead Researcher: Toshiharu Ikaga)" was developed in Yusuhara Town, Kochi Prefecture*3. Here, an overnight stay experience program was conducted to let elderly residents experience the difference between their own homes and a model house with high insulation and airtightness firsthand. Temperatures and humidity were measured in both the residents' homes and the model house, thermal images were taken, and home blood pressure and sleep quality were also measured, making it a program where results could be seen and felt. Participants reacted with comments such as, "The model house wasn't cold even in the hallway," "I realized how cold my own home is," and "I learned that my morning blood pressure is high on cold days," leading to awareness among residents. Furthermore, by having acquaintances participate together, comparisons were made not only between the model house and their own homes but also with their friends' houses, which contributed to those with particularly cold homes developing a sense of the problem (Figure 1).

Despite the home being a space where people stay for long periods, proper use of heating and cooling, ventilation methods, and insulation performance are not well known. In promoting zero-phase prevention, it is essential to know the current state of one's home and recognize the issues. While the overnight stay experience program is a typical example, why not start this winter by recording your home's morning and evening room temperatures and your home blood pressure? It might be even better to tackle it as a group.