Investigators were able to draw the conclusions using data from the Coronary Artery Risk Development in Young Adults Study, also known as CARDIA, which started following 5,115 participants between ages 18 to 30 more than 30 years ago, measuring their activity levels with an accelerometer, or activity monitor, that is similar to a pedometer. These decreases of physical activity over a 10-year period in middle age were observed in both men and women. However, the decline was steepest among black men who typically started being the most active but reduced their activity levels by nearly one hour daily. Black women began as the least active, and continued to have the lowest physical activity levels 10 years later. - www.sciencedaily.com