BACKGROUND
Physical inactivity is a risk factor for cancer that may be influenced by environmental factors. Indeed, dense and well-connected built environments and environments with natural vegetation may create opportunities for higher routine physical activity. However, studies have focused primarily on residential environments to define exposure and self-reported methods to estimate physical activity. The current study explores the momentary association between minute-level global positioning systems (GPS)-based greenness exposure and time-matched objectively measured physical activity.
METHODS
Adult women were recruited from sites across the US. Participants wore a GPS device and accelerometer on the hip for 7 days to assess location and physical activity at minute-level epochs. GPS records were linked to 250m resolution satellite-based vegetation data and Census Block Group-level EPA Smart Location Database walkability data. Minute-level generalized additive mixed models were conducted to test for associations between GPS measures and accelerometer count data, accounting for repeated measures within participant and allowing for deviations from linearity using splines.
RESULTS
Among 360 adult women (mean age of 55.3 ± 10.2 years), we observed positive nonlinear relationships between physical activity and both greenness and walkability. In exploratory analyses, the relationship between environmental factors and physical activity were strongest among those who were White, had higher incomes, and who were middle-aged.
CONCLUSIONS
Our results indicate that higher levels of physical activity occurred in areas with higher greenness and higher walkability.
IMPACT
Findings suggest that planning and design policies should focus on these environments to optimize opportunities for physical activity.