At least half an hour of moderate-to-vigorous physical activity five or more days a week is needed to reduce cancer risk, the American Cancer Society says.

New guidelines say this sort of workout is in addition to usual activity of daily life. Taking an occasional flight of stairs won't cut it any more.

Further, communities are urged to take a more active role in promoting a healthy environment with increased access to healthful foods and safe, enjoyable recreation areas.

Weight control, physical activity and dietary factors are the most important modifiable cancer risk factors among non-smokers, researchers say.

One-third of the more than 500,000 cancer deaths in the United States each year are attributable to diet and physical activity habits, such as being overweight, the report says.

Copyright 2006 by United Press International