What Scientists Learned About Fitness From Studying 11,000 Twins

A comprehensive national study has demonstrated a clear link between neighborhood walkability and increased walking activity among residents.

Analyzing data from approximately 11,000 twins, the research found that a 55% increase in walkability leads to a 23% increase in weekly walking minutes, highlighting significant public health benefits for the predominantly sedentary U.S. population.

Walkability’s Impact on Activity Levels

Adding compelling evidence in support of “walkable” neighborhoods, a major national study found that the built environment can indeed increase how much people walk.

Published today (December 12) in the American Journal of Epidemiology, the study examined data from about 11,000 twins, allowing researchers to account for family and genetic factors. They found that a 1% increase in a neighborhood’s “walkability” led to a 0.42% rise in walking within the area. Scaled up, a 55% increase in walkability could result in 23% more walking—equivalent to about 19 extra minutes per week for each resident.

Public Health Implications of Walkable Areas

Study lead author Glen Duncan, a professor of nutrition and exercise physiology at Washington State University, highlighted the public health significance of these findings for the highly sedentary U.S. populace.

“We have so many people in the U.S. population who don’t get sufficient activity. If we could shift the percentage of the population that just took on more plain old walking, we would see real health benefits,” said Duncan, who is also the director of the Washington State Twin Registry.

Characteristics of Walkable Neighborhoods

For the study, neighborhoods were deemed walkable based on an index that assesses the density of people, roads, and desirable places to walk to, such as stores, parks, restaurants, and coffee shops. The twin pairs in the study lived in all parts of the U.S., but the more walkable neighborhoods were typically found in urban areas.

Seattle’s Capitol Hill area is a good example of a walkable neighborhood, Duncan said, given its profusion of shops and restaurants, as well as access to public transportation such as buses and a light rail station. On the other side, more suburban or rural areas tend to be less walkable as they require driving to access things like grocery stores or other amenities.

Walkability and Transit Use

The study analyzed data from surveys of 5,477 pairs of twins taken from 2009 to 2020 which included information about where they lived and number of minutes walked in a typical week, whether for recreation, exercise or simply to get from one place to the other. The analysis revealed that those who lived in areas considered more walkable actually did walk more.

The researchers also looked at whether an area’s walkability increased transit use, but few study participants used public transit. However, living in a walkable neighborhood reduced the chance of having no transit use at all by 32%.

Exercise Beyond Walking in Walkable Areas

Living in a walkable area didn’t appear to have an effect on more vigorous exercise, but the authors note that this kind of exercise, which includes running and lifting weights, isn’t limited to the neighborhood environment. For example, a person could go for a vigorous bike ride that would take them well outside the boundaries of their neighborhood.

Simplicity and Benefits of Walking

Regardless, Duncan emphasized that walking is a great and easy way to improve health. It also counts toward the widely recommended 150 minutes a week of physical activity.     

“You don’t have to spend loads of money on fitness clothing and the best gear. Walking is a very natural thing. You just lace on some shoes and head out the door,” he said.

Reference: “Association between neighborhood walkability and physical activity in a community-based twin sample” by Glen E Duncan, Philip M Hurvitz, Bethany D Williams, Ally R Avery, Matthew J D Pilgrim, Siny Tsang, Ofer Amram, Stephen J Mooney and Andrew G Rundle, 12 December 2024, American Journal of Epidemiology.
DOI: 10.1093/aje/kwae170

In addition to Duncan, co-authors on this study include researchers from the University of Washington, University of Southern California, University of Virginia, Columbia University, and WSU.

Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.