National recommendations for physical activity
encourage all Americans to engage in regular physical activity and reduce
sedentary activities to promote health, psychological well-being, and a
healthy body weight.
Benefits of regular physical activity can:
Those who are just beginning to be physically active should start out slowly and gradually build to increase levels in order to prevent the risk of injury. It is important to:
The intensity of physical activity, or how hard your body is working, is typically categorized as light, moderate, or vigorous based on the amount of energy or effort a person expends in performing the activity.
Higher intensity activities require less time spent. Lower intensity activities require more time spent. Some examples of activities and their intensity levels are as follows:
Moderate intensity physical activity refers to a level of effort in which a person should experience some increase in breathing or heart rate. Examples of moderate intensity physical activity include:
Vigorous intensity physical activity refers to a level of effort in which a person should experience a large increase in breathing or heart rate. Examples of vigorous intensity physical activity include:
For a list of fitness related terms click here.
For infants and toddlers parents/care givers can promote physical activity by playing with infants and recognizing motor skills that will help the development of the child lead a more physically active life.

2005 recommendations for adolescents are to engage in at least 60minutes of moderate intensity physical activity. Examples of activity would be helping with yard work, bowling, dancing, etc..
Click here for an activity pyramid for children.
2005 recommendations for adults
are to engage in at least 30 minutes of moderate intensity
physical activity on most days of the week. Examples of activity would
be walking the dog, parking further away from stores, etc..
Click here for an activity pyramid for adults.

Adults who are able should engage in vigorous intensity physical activity 3 or more days of the week for 20 or more minutes per occasion. Examples of activity would be swimming, running, bicycling, etc...
References: Ainsworth BE, Haskell WL, Leon AS, et al. Compendium of physical activities: classification of energy costs of human physical activities. Medicine and Science in Sports and Exercise 1993;25(1):71–80.Borg G. Perceived exertion and pain scales. Champaign (IL): Human Kinetics, 1998.