Researchers from Stanford University have found that moving to a more walkable city leads to a significant increase in daily physical activity. The study, published in Nature, used smartphone data from over 2 million Americans and tracked 5,400 individuals who relocated between cities during a three-year period.
“This natural experiment sought to answer an important yet challenging question that the public health field has been attempting to answer for decades, which is whether changes in people’s built environments can actually lead to changes in their physical activity levels,” said study author Abby King, a professor of epidemiology and population health at Stanford Medicine.
The analysis revealed that those who moved to cities with higher Walk Scores—an index measuring walkability on a scale from 0 to 100—increased their average daily steps by about 1,100, or roughly 11 extra minutes of walking each day. For instance, participants relocating from less walkable areas to New York City (Walk Score 89) saw their daily step count rise from 5,600 to 7,000. Conversely, those leaving highly walkable places for less walkable ones experienced a decrease in daily steps.
“It was exciting to have this rich, longitudinal dataset with activity across months and years to unravel how your environment impacts your activity,” said Jennifer Hicks, executive director of the Wu Tsai Human Performance Alliance at Stanford University.
The researchers used data collected via the Azumio Argus fitness app and examined over 248,000 days of minute-by-minute step counts. By comparing individual step counts before and after relocation while accounting for factors like age and body mass index (BMI), they aimed to isolate the impact of urban design on behavior.
“I was surprised and incredibly encouraged by the fact that greater walkability led to significantly greater daily steps across nearly all age and gender groups,” Hicks noted. “Individuals had greater daily steps in a more walkable city regardless of how active they were before they moved and regardless of what their body mass index is.”
One exception was older adult women; for this group, increased city walkability did not correspond with more walking—a result suggesting other barriers may exist.
While previous research has indicated an association between neighborhood design and physical activity levels, many studies relied on self-reported data or could not determine cause-and-effect relationships. This study’s approach allowed researchers to control for personal preferences by showing movers’ demographic characteristics were similar regardless of where they relocated or their prior activity levels.
Data shows most people move due to family or work reasons rather than seeking out more walkable neighborhoods. As such, the observed changes in physical activity appear linked directly to differences in local infrastructure rather than individual motivation or lifestyle choices.
America faces increasing rates of inactivity; more than one-quarter of U.S. adults do not get enough exercise according to CDC estimates. Physical inactivity is linked with chronic conditions such as obesity and cardiovascular disease. The findings suggest that improvements in urban design could help address these public health challenges by encouraging more walking among residents.
To assess potential impact at scale, researchers modeled how increasing all U.S. locations’ Walk Scores might affect national exercise rates. If every location matched Chicago or Philadelphia’s level (Walk Score 78), an estimated additional 36 million Americans would meet recommended guidelines for aerobic exercise per week; if matching New York City’s score (89), that number could rise by up to 47 million people meeting these standards.
“While most of the digital health interventions and programs currently being offered in the physical activity area have been focused almost exclusively on the individual, behavioral scientists have long known that behavior doesn’t occur in a vacuum,” King said. “The physical and social contexts surrounding all of our behaviors play a huge role in affecting what we do on a daily basis. This study adds significantly to that body of research.”
Authors note limitations including possible bias toward higher-income individuals already interested in tracking fitness due to reliance on smartphone app data. Additionally, only step-based activities were measured; forms like cycling or swimming were excluded.
“Despite the explosion of wearable devices and smartphone apps to track physical activity and other health behaviors,” added Hicks, “we have only scratched the surface here in terms of our ability to learn how to use this data to help people be more active and optimize their health and performance.”
This project was part of Stanford’s Wu Tsai Human Performance Alliance Digital Athlete Moonshot initiative with support from agencies including the National Institutes of Health and Bill & Melinda Gates Foundation.
