Physical activity is associated with better health; however, the optimal 
intensity of activity remains unclear. A total of 13,485 men (mean age, 57.5 
years) from the Harvard Alumni Health Study reported their walking, stair 
climbing, and sports/recreation in 1977. Between 1977 and 1992, 2,539 died. 
After adjusting for the different activity components, distance walked and 
storeys climbed independently predicted longevity (p, trend = 0.004 and <0.001, 
respectively). Light activities (<4 multiples of resting metabolic rate (METs)) 
were not associated with reduced mortality rates, moderate activities (4-<6 
METs) appeared somewhat beneficial, and vigorous activities (> or =6 METs) 
clearly predicted lower mortality rates (p, trend = 0.72, 0.07, and <0.001, 
respectively). These data provide some support for current recommendations that 
emphasize moderate intensity activity; they also clearly indicate a benefit of 
vigorous activity.