We weren't designed to sit. The body is a perpetual motion machine.

 (Dr. Joan Vernikos)

 Sitting is more dangerous than smoking, kills more people than HIV, and is more treacherous than parachuting. We are sitting ourselves to death. The chair is out to kill us.

(Professor James Levine, The Mayo Clinic) 

Sitting is the new smoking...

 https://www.startstanding.org/sitting-new-smoking/#extended