Here's a quick and simple aerobic exercise you can do while seated.
Step 1: Sit in your chair with your feet flat on the ground, shoulder-width apart.
Step 2: Alternating your arms, pump them vigorously over your head for thirty seconds.
Step 3: Tap the balls of your feet of the floor, first the right and then the left, football-drill style, for 30 seconds.
Step 4: Repeat the entire exercise five times.
See the complete library of Workplace Fitness exercises.