If you sit at a desk for long periods every day you could be losing a crucial few inches from your possible height, as well as setting yourself up for more health problems in the future. The good news is that this can be simply rectified if you perform these exercises in the office as often as possible.
Sorting out your posture is the first step to feeling and looking taller. Bad posture can shorten the spine by several inches. Poor posture can either be caused by structural problems in the middle back where the vertebrae are naturally wedge-shaped, or by functional limitation in the lower back with a rear-tilted pelvis rounding the shoulders significantly, especially when sitting.
Here are two spine-lengthening exercises that will combat the effect of sitting still:
Shoulders forward - Stretch the chest: stand in an open doorway and put both arms on the frame at shoulder height. Keeping the spine straight, step through the door with one foot, and stretch out the pectoral muscles, which are frequently too strong and tight and pull the shoulder forwards.
Shoulders back - Stand up and pull the shoulder blades both together and down to the buttocks. Stand with your chest out for it to be above the lower back and not in front of it and your chin tucked in, while looking straight ahead. Activate your oblique muscles to hold this pose.