The advice to "sit up straight" is well meant, and almost useless. It treats posture like a pose you can hold, when the real trouble is time: any position, held long enough, becomes the wrong one.
Stillness is the actual problem
A perfectly upright spine held for three hours puts steady load on the same discs and muscles the whole time. Your body is built to move — small, frequent shifts are how it keeps tissue fed and joints comfortable.
- Change position every 20–30 minutes, even slightly.
- Let the backrest and cushion do the holding, not your muscles.
- Stand for a phone call you'd normally take sitting.
Rotate, don't lock
Think of good sitting as a range you move through, not a single correct shape. Support that follows your lower back as you shift makes that rotation effortless — which is the whole point.
So the better instruction isn't "sit up straight." It's "don't stay still."
