Should You Always Sit up Straight?

They found that sitting up straight strains your back unnecessarily. ... Ideally, you should lean slightly back, at an angle of about 135 degrees, they say.

Should I always sit straight?

Here's a quick posture check-in: When sitting, your feet should rest flat on the floor, with even weight on both hips. Your back should be mostly straight (you'll have natural curves in your lumbar, thoracic, and cervical areas).

Why is it uncomfortable to sit up straight?

And there's a reason for this: your body is trained to believe that your not-so-great way of sitting or standing is “normal” so anything that isn't that (i.e. sitting up straight) feels uncomfortable because your muscles aren't trained to keep your torso supported in that manner.