Try the Seated Sun Pose - it improves circulation to your head , massages internal organs, and limbers your spine and hips. 
Sit back in your chair with your legs slightly wider than hip width apart. Breathe out completely then breathe in and with a sweeping motion bring your arms up over your head. Look up and stretch. Breathe out while bending forward between your legs and if you can put your palms on the floor. Slowly breathe in while raising back up with arms over head again, then loer your arms to the side.