Sitting in a slouched position puts a lot of pressure on the discs of the lower back. Research has shown that pressure on the discs when sitting slouched, is similar to the pressure created by jumping! If you sit slouched 8 hours a day, you may be putting your spine under that level of stress. Good posture of the spine begins with the pelvis, because the pelvis is the platform of the spine. Here is a suggestion to sit with a comfortable straight spine/back.
1.Start by sitting up straight, feet flat on the floor hip width apart, hands on the top of each thigh. I sit toward the middle/front of the chair
2. Find your sitz bones or butt bones, they align with your pelvis.
3. Then place one of your hands on the very bottom of your lower back, right near the tail bone, now slide the hand up to the waist, imagine your back gently lengthening. At the same time lean forward from your hips about an inch, so your stomach is now slightly over your hips. Find your comfortable position without any strain.
Now your back is nice and straight without any pressure on your lower back! It's also a great way to work your stomach at the same time.
How long does is take for this to feel comfortable? Practicing this in your daily routine, you will find it uncomfortable to sit slouched.
If you want more information on this, come to my Pilates Studio and take one of my Mat Classes or Private Sessions.