Saelens 2003 - “Neighborhood-Based Differences in Physical Activity: An Environment Scale Evaluation”

Saelens, Brian E.; Sallis, James F.; Black, Jennifer B.; Chen, Diana.
“Neighborhood-Based Differences in Physical Activity: An Environment Scale Evaluation”
American Journal of Public Health
September 2003; v.93, n.9.
On the Web
Relevance: high

Saelens et al conducted a small preliminary study using accelerometers and surveys to analyze how activity levels and body mass indexes differ between two neighborhoods: one with high-walkability, one with low-walkability.  They found that residents of high-walkability neighborhoods walked more for errands, engaged in more moderate to vigorous physical activity, and were less likely to be overweight.  Interestingly, this study suggests that walkability primarily affects walking for errands but not walking for exercise.

Residents of the high-walkability neighborhood engaged in 70 more minutes of moderate to vigorous physical activity (211 vs. 140 min.) and had lower overweight prevalence (60.4% vs. 35.2%) than did residents of the low-walkability neighborhood.

While a higher percentage of high-walkability residents walked for errands (85.2% vs 59.6%) and breaks at work/school (50% vs 25%), only the difference in walking for errands remained significant after adjusting for age and education level.  Walking for exercise did not differ significantly, although low-walkability residents reported more places to walk/bicycle than did high-walkability residents.  High-walkability residents scored their neighborhoods higher on other measures of walkability, such as land-use mix, aesthetics, pedestrian safety, and crime safety.

"A 70-minute-per-week difference in physical activity translates to walking 3 miles more per week given an approximate 20-minute-per-mile pace.  Over the course of the year, this amount of walking would yield about 15,000 kilocalories of energy expended for a 68 kilogram person, which, if not offset by caloric intake, could result in almost 1.8 kilograms of weigh loss."

Comments

[Eric de Place]

Does that 70-minute/week difference adjust for age and education? It seems like that's the crux. Caloric intake held constant, the potential to drop 4 pounds of weight a year is astonishing. (So astonishing, in fact, that I'm a tad skeptical.)

What's the sample size?

What's the definition of walkability? How residents describe their neighborhoods?