Diagnosing physical activity in 4D: Spatial-temporal physical activity behavior of Dutch adults aged 45-65 years

Abstract

Insufficient physical activity (PA) is a major public health problem as it is one of the leading risk factors for death and it increases the risk of various non-communicable diseases. Therefore, the societal burden of physical inactivity due to morbidity, mortality, and the associated health care costs is high. Hence, global agencies like the World Health Organization and local policy-makers emphasize the importance of increasing PA levels more and more. Integrating sufficient PA in daily life may be particularly difficult for adults aged 45 to 65 years, as they often combine a demanding job with taking care of their children and their aging parents. This makes these midlife adults an important target group for increasing PA. Previous studies have shown that the (built) environment could offer (new) opportunities to stimulate PA. Although some environmental factors have been linked to PA behavior, there are still gaps that need further investigation. First, previous studies have mostly focused on the role of neighborhood environmental factors, whereas other environments (and their characteristics), such as the work environment or the route from home to work, may also be of great importance for daily PA. Second, PA is not only organized in space, it also has a temporal structure, which is less well studied. This thesis addressed these gaps from a time-geography perspective, using a combination of GPS- and accelerometers to map PA behavior of adults aged 45 – 65 years objectively in space and time. This thesis showed that the use of accelerometers allowed for the distinction of four different hour-by-hour PA patterns: a morning light PA pattern, a mid-day moderate-vigorous PA pattern, an active pattern, and an inactive pattern. Individuals with different PA patterns also appeared to differ regarding several individual characteristics (e.g. ethnicity) and neighborhood environmental characteristics. Findings of the thesis also suggest that the field of PA research should put PA in a broader geographical context, as the results showed that a variety of locations is important for adults’ PA behavior. For example, most time in moderate-vigorous PA was spent at home and at work, whereas the remaining time spent in moderate-vigorous PA was approximately equally distributed across environments such as sports facilities, green spaces, and shopping centers. Still, the residential neighborhood is of importance for PA as well. This thesis showed that objectively measured neighborhood characteristics were associated with neighborhood-based PA. These associations were in particular found for moderate-vigorous PA and areas close to adults’ homes (i.e. within 400 meter from home). Furthermore, different types of natural environments facilitated different types and intensities of PA. The size of natural environments was of importance as well, as results showed that larger-sized natural environments were associated with higher levels of light and moderate-vigorous PA. Broadening the geographical context of PA can also lead to a more beneficial cooperation of various policy domains that may all benefit from environmental interventions increasing PA levels.