Why pedestrian and bike friendly cities are better than exercise

    My recent trip to the ACSM annual meeting dramatically underscored the impact that walkable and bike able communities can have on daily activity patterns. In just a few short years, Denver, CO, has made huge strides to its pedestrian and cycling infrastructure, creating a community that accommodates both cars and human modes of transportation, including the Denver B-cycle bike share program. In some contrast, Richmond has continued to struggle with implementing its own infrastructure by seemingly installing traffic infrastructure that in some cases actually makes streets less safe for pedestrians and cyclists (as well as failing to enforce basic traffic laws). Nonetheless, many recognize the overall value of such infrastructure changes on a community. Therefore, I wanted to highlight some of those benefits, as well as relate my own experience on my trip in this short article.
Smart cities, lead to better health and lower costs
     Rather than write pages of benefits that have already been published, I’m going to cut right to the chase. People who live in walkable, cycling friendly cities (WCFC) are not only thinner and healthier, the air quality in WCFC’s is generally better. Moreover, transportation costs are also lower. For example, a 2006 paper by Frank et al. found that an increase in walkability of just a 5% is associated with a per capita increase of 32.1% physically active travel, a 0.23-point drop in BMI, a 6.5% decrease in vehicle miles traveled, and more than a 5% drop in air pollution. Other studies have noted similar findings, as well as 50% lower transportation costs, saving more than $8000/year (Littman 2007). But just because you offer such infrastructure, it does not mean people will actually use it, or will they?
If you build it, they will come
    One common argument that I hear is that it costs too much money to change infrastructure and transportation that people won’t use. The evidence, however, suggests that investment in WCFC infrastructure results increased reliance on non-vehicular transportation. Drawing on twenty years of infrastructure investment in Boulder, CO, Henao et al. (2015) noted that the use of walking, cycling, and transit increased nearly 0.5 % each year over a 20 year period. In my own anecdotal experience, the completion of the Virginia Capital Trail has dramatically increased both walking and cycling in the surrounding community, particularly among minorities, who I never used to see out on bikes.
Real world experience
    During my trip to Denver, I either walked or rode (using the bike share) Sunday – Friday. In that time, I accrued nearly 85,000 steps. Using a very conservative estimate for step length of 1.5 feet/step (vs the internets 2.5 ft), that amounted to nearly 24 miles of walking over 6 days, and 20 miles of bike riding. Counting my handful of short runs and a swim, I achieved MORE THAN 13.5 HOURS of activity; well above any typical training week. Even conservatively estimating a caloric expenditure of 400 kcal/hour, results in a weekly expenditure of 5500 kcal.
    The point of all this math is not to impress anyone. Rather, its to impress upon us how our country can reduce obesity and be far healthier than we are by building cities around pedestrians and cyclists and not cars. Its also to illustrate why exercise, as is typically done, 3 -4 days per week, is wholly inadequate for reducing obesity. There was nothing super human about my daily activity, nor impressive. I used the lack of time I had to both transport myself and increase my overall activity. Rather than lamenting how one does not have time to exercise, relying on our own two legs would result in significant caloric expenditures and dramatic improvement in health.

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