During the past four decades, obesity levels in the United States have risen dramatically. The rates of chronic disease — including heart disease, stroke, diabetes, some types of cancer, sleep disorders, joint pains, mental illness and depression — have similarly risen while the amount of physical activity that Americans participate in has steadily decreased. Fortunately, cycling offers a low-impact form of physical activity that appeals to a wide range of the population.
Perhaps the two greatest environmental benefits of bicycling are that it produces no pollution and consumes no fossil fuel. Annual emissions of greenhouse gases (GHG) in the U.S. are projected to increase by 35 percent between 2005 and 2030, from 7.2 to 9.7 billion tons CO2 equivalent, a standardized measure of GHG emissions. The greater the number of trips made by bicycle, the slower the rate of increase.