The sedentary lifestyle of most Americans and the effects of inactivity on their health and function are of increasing concern. Researchers at the University of Michigan's School of Public Health found that many American women in their forties and fifties have the strength and fitness levels that you'd expect to see in their great-grandmothers. This means they have trouble carrying groceries, climbing stairs and walking around the block.

• By age 75, 42% of women could not stand for over 15 minutes, 20% were unable to climb stairs, and 33% were unable to lift a weight over 10 pounds (e.g., a 3 month old grandchild).
  
  
• By age 85, about 50% of the older adults required the assistance with their activities of daily living ADLs such as walking, bathing, eating, dressing, and using the toilet. (Branch, Katz, and colleagues, 1984)
  
  
• Older persons who engaged in vigorous running and other aerobic activities had lower death rates and slower development of disability compared to those in the more sedentary control group. (Fries, Singh and colleagues, 1994)
  
  
• When physically fit men in their fifties were compared to inactive men in their 20's, the physically fit older men had significantly lower resting heart rates-- 64 beats per minute versus 85 beats per minute than the younger men, more efficient oxygen uptake, and they weighed less.