The Centers for Disease Control and Prevention in Atlanta recommends adults do 2 hours and 30 minute of moderate-intensity aerobic activity such as brisk walking every week and muscle-strengthening activities on two or more days a week that work all major muscle groups -- legs, hips, back, abdomen, chest, shoulders and arms.
Amy L. Freeland, Andrew L. Dannenberg and Arthur M. Wende, all of the National Center for Environmental Health, Healthy Community Design Initiative at the CDC; and Shailendra N. Banerjee of the National Center for Environmental Health, Emergency and Environmental Health Services at the CDC assessed changes in transit-associated U.S. walking from 2001 to 2009.
They used data from the National Household Travel Survey, a telephone survey administered by the U.S. Department of Transportation to examine travel behavior in the United States.
The study, published in the American Journal of Public Health, found those who walked to mass transit in large urban areas with a rail system were 72 percent more likely to transit walk 30 minutes or more per day than were those without a rail system.
In addition, from 2001 to 2009, the estimated number of transit walkers rose from 7.5 million to 9.6 million -- a 28 percent increase; those whose transit-associated walking time was 30 minutes or more increased from approximately 2.6 million to 3.4 million, a 31 percent increase.
Transit walking contributes to meeting physical activity recommendations, the study authors concluded.
Notable deaths of 2014 [PHOTOS]