Metabolism slows down 90 percent after 30 minutes of sitting. The enzymes that move the bad fat from your arteries to your muscles, where it can get burned off, slow down. The muscles in your lower body are turned off.
And after two hours, good cholesterol drops 20 percent. Just getting up for five minutes is going to get things going again.

These things are so simple they’re almost stupid.

(Gavin Bradley)

 The risk of heart failure was more than double for men who sat for at least five hours a day outside of work and didn't exercise very much, compared with men who were physically active and sat for less than two hours a day.

 (Dr. Deborah Rohm) 

 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