An estimated 100,000 older adults will participate in local fitness activities throughout the country on May 26 as part of the 17th annual National Senior Health & Fitness Day. Senior centers, health clubs, hospitals, parks and recreation departments, and retirement communities will host some 1,000 events. Typical programs include small group exercise demonstrations, walking tours and health fairs. Nationally, the initiative is orchestrated by Mature Market Resource Center, an information clearinghouse for older adult programs.