In Japan, life expectancy has increased over the last seven years, and this includes “healthy life expectancy” which indicates the years of living in full health without disease and/or injury. However, the gap between life expectancy and healthy life expectancy—nine years for men and twelve years for women—called the unhealthy period, has not changed. Therefore, it is important to shorten the unhealthy period and extend healthy life expectancy to improve the quality of life (QOL) and reduce social security expenses. To do so, it is effective to promote walking, which accounts for 80% of daily physical activity.
There are two approaches to increasing physical activity by walking: the first is to increase the quantity of walking. Many studies focus on built environmental factors to increase walking by personal attributes. The second is to improve the quality of walking, however, only a handful of studies exist on built environmental factors that improve the quality of walking. As an index for the quality of walking, we defined walking intensity by dividing the amount of physical activity by step counts as of March 2017, and analyzed its relationship with built environmental indices (steepness, population density, commercial area ratio, improvement of footpaths, and distance to the nearest station, community center, park, and hospital).
The sample consisted of 10,599 middle-aged men in 281 neighborhoods, 17,752 elderly men in 295 neighborhoods, 15,481 middle-aged women in 293 neighborhoods, and 20,069 elderly women in 296 neighborhoods. First, we analyzed geographical features of walking intensity by creating maps. Second, we analyzed the relationship between built environmental indices and walking intensity by gender and generation using multiple regression analysis.
By creating maps, we found areas that had similar walking intensity in all generations and both genders. In the multiple regression analysis, steepness, distance to the nearest station and hospital, population density, and improvement of footpaths had a significant relationship to walking intensity in any gender and generation. Specifically, we found significant non-linear relationship between distance to the nearest station and walking intensity in middle-aged men. The correlation between steepness and walking intensity was significant only in women; the correlation was positive in middle-aged women and negative in elderly women.
In conclusion, we offered two suggestions. First, we found low walking intensity near stations, which seemed to be due to obstacles to walking, such as high traffic density and narrow sidewalks. The walking environment near station areas must be improved. Second, the relationship between steepness and walking intensity in women was inconsistent by generation, which suggested that the required improvements to built environments differed. In future studies, longitudinal research or research with other generations like rising generation should be conducted to measure changes of participants’ walking intensity.
