More than 21 million US adults 18–64 years of age have a disability. These are adults with serious difficulty walking or climbing stairs; hearing; seeing; or concentrating, remembering, or making decisions. Most adults with disabilities are able to participate in physical activity, yet nearly half of them get no aerobic physical activity. Physical activity benefits all adults, whether or not they have a disability, by reducing their risk of serious chronic diseases, such as heart disease, stroke, diabetes and some cancers. Only 44% of adults with disabilities who visited a doctor in the past year were told by a doctor to get physical activity. Yet adults with disabilities were 82% more likely to be physically active if their doctor recommended it.