Sitting most of the day (i.e. with almost all of your muscles relaxed) is associated with dozens of diseases and early death. Any chair that lets you relax you

Sitting most of the day (i.e. with almost all of your muscles relaxed) is associated with dozens of diseases and early death. Any chair that lets you relax your legs or disengages your hips is very bad for your health. Any chair that also relaxes your spine is even worse. The author basically nails it: either pick a chair so basic you're forced to engage your hips and spine to spread the load and maintain posture, or go with an active option like a medicine ball or stand-up desk.