Introduction
Outdoor physical activity, particularly walking, plays a key role in maintaining health and mobility in old age [1–3]. Physical activity refers to activities performed in daily life and includes activities such as those related to occupation, leisure-time, housework and transportation. The majority of moderate intensity physical activity in older adults occurs outside of the individual’s home [4,5]. Furthermore, a higher frequency of leaving the home is beneficial for maintaining health and function [6–8], and being able to go beyond the own neighborhood has been associated with positive health outcomes, such as higher physical and cognitive function [6–9].