A new report from the Centers for Disease Control and Prevention has found that about half of Americans are sitting for too many hours a day and not receiving any exercise at all.

A survey of 5,900 adults found that about 26% of people sit for more than eight hours a day, and 45% do not get any moderate or vigorous exercise during the week. About 11% of adults sit for more than eight hours a day and are not physically active.

A separate survey has shown that 86% of American workers sit all day for their jobs, putting them at risk for “sitting disease” and contributing to the problem of prolonged sitting.

Peter Katzmarzyk, study co-author, said, “In recent years, we have begun to understand the health hazards of excessive sitting.”

Doctors are still unsure of why prolonged sitting is bad for health, but Katzmarzyk speculates that “when people sit, they deactivate the large muscles in their legs, and this has a host of metabolic consequences that seem to be harmful.”

Programs designed to increase physical activity and reduce sitting can be especially beneficial for reducing health risks, Katzmarzyk notes.

As the number of smokers has declined in the U.S., poor diet and lack of exercise are becoming the leading causes of premature death and chronic diseases. But experts say that simply standing up, moving around and sitting less often can benefit your health.

The latest edition of the U.S. Physical Activity Guidelines for Americans states that any amount of physical activity, even just two minutes of activity, can provide significant health benefits.

When these new guidelines were released, Adm. Brett Giroir, assistant secretary for health at the U.S. Department of Health and Human Services, said, “Physical activity is about finding opportunities to add movement throughout the day as part of a bigger commitment to healthy living.”

“The main idea is that regular physical activity over months and years can produce long-term health benefits,” the study states.

Giroir says that sedentary lifestyles cause 10% of premature deaths in the United States. He notes that getting the recommended 150 minutes of moderate exercise per week could help prevent nearly 75,000 premature deaths each year.

These guidelines are issued by the U.S. Department of Health and Human Services and is in conjunction with the Dietary Guidelines for Americans. It is a joint effort between the HHS and the U.S. Department of Agriculture, the study states.