In his book, "Get Up!: Why Your Chair Is Killing You and What You Can Do About It," Dr. James Levine, co-director of the Mayo Clinic and the Arizona State University Obesity Initiative, notes there are about 10,000 publications showing that sitting is harmful to your health.

Prolonged sitting actively promotes dozens of chronic diseases, including obesity and Type 2 diabetes, even if you're very fit and exercise regularly. It's also an independent risk factor for premature death, even if you lead an otherwise healthy lifestyle. In fact, chronic sitting has a mortality rate similar to smoking.1

Studies looking at life in agriculture environments show that people in agrarian villages sit for about three hours a day. Meanwhile, the average American office worker can sit for 13 to 15 hours a day, and research shows that vigorous exercise cannot counteract the adverse effects of this prolonged sitting.

Interestingly, evidence of the biological effects associated with lack of movement go further back than you might think — straight into the human fossil records, as reported by NPR in 2014 (audio above).

According to biological anthropologists at the Smithsonian National Museum of Natural History, the fossil record suggests that when early man traded their nomadic hunter-gatherer lifestyles for a more settled one, it resulted in a less dense bone structure. As reported by NPR:2

"The lightweight bones don't appear until about 12,000 years ago. That's right when humans were becoming less physically active because they were leaving their nomadic hunter-gatherer life behind and settling down to pursue agriculture.

A report on the work appeared … in the Proceedings of the National Academy of Sciences,3 along with a study from a different research group that came to much the same conclusion.