Most people intuitively recognize that physical inactivity and prolonged sitting are not healthy. New research shows that these behaviors may also increase your risk of cancer.

Sitting for too long may be responsible for more than 90,000 new cases of breast and colon cancer each year, researchers said in a presentation made this week at the American Institute for Cancer Research (AICR) in Washington, D.C. The estimate was further broken down by type of cancer: breast (49,000 cases) and colon (43,000 cases).

Analysis was based on U.S. physical activity data and cancer statistics, as well as more than 200 international cancer studies in which physical activity reduced the risk of these cancers by 25 to 30 percent, said researcher and Canadian epidemiologist Christine Friedenreich.

“This gives us some idea of the cancers we could prevent by getting people to be more active,” Friedenreich said.

"A brisk daily walk of at least 30 minutes could lower a person's risk over time for breast cancer and colon cancer," said Alice Bender, a registered dietitian with AICR.