Adjusting Your Chair Contrary to popular belief, sitting, which most people believe is relaxing, is hard on the back. Sitting for long periods of time can cause increased pressure on the intervertebral discs the springy, shock-absorbing part of the spine. Sitting is also hard on the feet and legs.
Gravity tends to pool blood in the legs and feet and create a sluggish return to the heart.
When performing daily tasks, alternate between sitting and standing. Adjust height of backrest to support the natural inward curvature of the lower back. It may be useful to use a rolled towel or lumbar pad to support the low back. The backrest angle is set so that your hip-torso angle is 90 degrees or greater. Sit upright in the chair with the low back against the backrest and the shoulders touching the backrest.