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

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

──There are passengers hesitant 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 belief 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 something that leaves an impression of this, there is a research study that verified environmental factors contributing to walking among approximately 4,000 elderly residents in Fujisawa City, Kanagawa Prefecture. Here, walking associated with daily life and walking for health promotion were classified, and factors corresponding to each were identified. It was shown that "seeing people exercising in the neighborhood" and "having good scenery in the neighborhood" encourage residents to walk. These results suggest the possibility that the community, which encompasses the surrounding group and the formed environment, influences individual health promotion behaviors. This is thought 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 activity is said to play an important role in maintaining and promoting health, such as preventing heart disease, stroke, diabetes, high blood pressure, 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 carried out to solve issues related to lifestyle-related diseases. From fiscal 2013, "Health Japan 21 (the second term)" began as its second phase, aiming to extend healthy life expectancy and improve dietary habits and exercise habits, with target values set for each sector. In the physical activity and exercise-related sectors, there was a shift from the evaluation values of motivation and drive used up until the first term, and behavioral indicators such as "increasing the number of steps in daily life" and "increasing the percentage of people with exercise habits" came to be emphasized. Table 1 shows those target values and the interim evaluation values as of fiscal 2016. First, focusing on the number of steps, the baseline value as of 2010 was 7,841 steps for men and 6,883 steps for women, which did not reach the targets of Health Japan 21 (the first term). Looking at the interim evaluation values for 2016, it can be seen that far from reaching the target values, the figures have slightly worsened compared to the 2010 values over these six years. The same trend applies to the percentage of people with exercise habits. While the impact of an aging population can be considered to some extent, from a strict perspective, it could be said that previous efforts related to physical activity and exercise have continued to fail.

As described, no improvement was seen regarding the increase in the number of steps in daily life 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 approach to individuals through health guidance, and it is necessary to promote the creation of an environment that makes people walk without each individual being conscious of it.

This brings to mind the results of the Fujisawa City study mentioned earlier. If seeing people exercising in the neighborhood contributes to the promotion of walking, then we should develop walking routes with excellent scenery and create a trend where people walk. If the enhancement of scenery through the maintenance of flowerbeds promotes going out, and if people who participate in community activities become healthy, then the creation of flowerbeds 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 particularly earnestly in Health Japan 21, measures for "Zero-Phase Prevention" are becoming more emphasized. As the word "zero" suggests, it refers to prevention at a stage prior to primary prevention. With the goal of "preventing the occurrence of socio-economic, environmental, and behavioral conditions that cause undesirable lifestyle habits," it refers to efforts that aim to link 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 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 when waking up leads to increased blood pressure; a cold living room before bed leads to nocturia and worsened sleep quality; and people who use kotatsu (table heaters) spend more time sitting, which decreases their physical activity level. Eliminating conditions such as undesirable heating behaviors and cold exposure as described above is thought to be a form of zero-phase prevention that unconsciously leads residents to a long and healthy life.

As described above, there are many hidden factors in homes and communities that contribute to extending people's healthy life expectancy, and by controlling these well, there is a possibility of linking 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 night at all," despite spending time in an environment that dropped below 5°C at night. Upon interviewing them, they said, "I've lived in this house forever, so this is normal." Many similar responses existed, and I witnessed the deep-rooted nature of the problem.

To consider countermeasures for this social issue, a project titled "Creation of Housing and Communities that Realize Healthy Longevity (Research Representative: Toshiharu Ikaga)" was developed in Yusuhara Town, Kochi Prefecture*3. Here, a residential experience learning program was conducted to let elderly residents in the town experience the difference between a model house with high insulation and airtightness and their own homes firsthand. Temperature and humidity were measured, thermal images were taken in both their own homes and the model house, and home blood pressure and sleep quality were also measured, making it a program that could be felt both visually and physically. 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 found 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 the homes of their acquaintances, 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 a long time, proper ways to use 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 residential 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.