References:
Pollock, Michael L. Ph.D., FACSM ; Gaesser, Glenn A. Ph.D., FACSM ; Butcher, Janus D. M.D., FACSM; Després, Jean-Pierre Ph.D.; Dishman, Rod K. Ph.D., FACSM; Franklin, Barry A. Ph.D., FACSM; Garber, Carol Ewing Ph.D., FACSM(1998)
ACSM Position Stand: The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults
The first link is ACSM for senior fitness:
The second link is ACSM for apparently healthy adults:
>Guidelines from US Department of Health and Human Services: