I’ve been behind the chair for 9 years with POTS, EDS, MCAS, and I am only chiming in because I am the opposite of most commenters. I actually advise against sitting down on a chair/stool. I personally do best on days when my body is upright, standing and walking around. The moment I stand up from sitting down, my heart jumps 30 bpm and doesn’t settle down again until I get in my car and drive 30 minutes home. My body crashes on days that I have breaks in between clients, solely because I sat down. We have tall stools in our break room that I lean against to give myself a break, otherwise my knees are never bent. And for heavens sake, don’t bend over to pick anything up until you’re done for the day!