Population studies have confirmed that a combination of external stimulation (e.g., physical exercise, solitary leisure activities, attendance at religious events, activities of daily living) are associated with a reduced mortality in old age. Greater social networks and social engagements are associated with a reduced cognitive decline in elderly individuals. Use any type of stimulation (e.g., physical, mental, social, sensual, spiritual) to keep your body and mind agile and energetic. (BLS Newsletter, May 2011. Kyriazis, Marios, MD. Source)