The researchers pored through data from the NIH-Formerly AARP Diet and Health Study to examine "how leisure-time physical activity participation from adolescence (15–18 years) into early (19–29 years), middle (35–39 years) and later adulthood (43–64 years) is associated with subsequent Medicare costs." They ultimately tracked the healthcare costs of 21,750 people who responded to in-depth questionnaires about their physical activity. As expected, cost-savings were significant. Adults who maintained moderate or high physical activity throughout life saved around $1,300 per year in Medicare costs after age 65. Adults who were most active in early adulthood saved $1,874 dollars in yearly Medicare costs. Higher physical activity in middle age was particularly effective at lowering average annualized total healthcare costs after age 65. People who exercised between one and three hours per week during this time saved $1,365 compared to people reporting less than one hour of activity. People who exercised 7+ hours saved $2,079.