It is estimated that just 150 minutes of cycling or walking spent by each adult per week could save the US economy about $28 billion a year. Yet, cycling and walking still lack the widespread popularity required to realize this level of economic benefit.

Between 2007 and 2016, despite a slight increase in the number of people walking or biking to work, only 3.4 percent of the total US population commuted by foot or bike, according to the Alliance for Biking and Walking. In the most populous cities, however, this proportion is higher with an average of 6.4 percent of people biking or walking to work.

Beyond personal health and leisure preferences, structural barriers exist that prevent stronger growth in biking and walking, including a lack of infrastructure, weather, and the distance between residence and place of employment.

The popularity of bicycling and walking emerges in studies of general physical activity in the United States. States in which biking and walking to work are more common also report higher shares of the population engaging in at least 150 minutes of physical activity per week.

Residents of Oregon, Colorado, and Hawaii lead the country in meeting the recommended weekly physical activity levels and are also among the top 10 states for biking and walking to work. The question becomes, does walking and biking lead to more physical activity, or do physically active people walk and bike more often? We'll leave that to the researchers to answer.

The popularity of cycling and walking remains widely divergent among the 50 states, suggesting that health insurers to government planners should take heed in developing incentives to encourage these forms of physical activity.