We must always stand or sit as straight and upright as possible.
The fact is that there is no perfect posture that we should remain in for hours.
Our body works best when we move so if our back is sensitive then we would do better trying to change things up every 20 minutes or so.
And to be honest, when it comes to pain and posture, making ourselves sit or stand with an exaggerated ‘good posture’ can actually cause more problems. Think shoulder blades pulled back, tummy muscles pulled in tight, and sitting very tall in the chair. Contracting all our muscles in this way can be very irritating for our bodies and very tiring for our muscles. It may be something that we’ve all learned to do but for most people it really doesn’t help in the long run.
There is no perfect posture. Once again, moving often is key!