The name of today's exercise is not to be confused with Death March, even though you might feel like you're at the end of the wire, energy-wise, the Desk March is a way to keep in step while you work. Studies by several medical research groups indicate that people who sit at their desks all day are more likely have to heart problems than those who rarely sit. You can do steps one and two of this exercise without missing a beat in your work.
Step 1: While seated, alternate walking in place on your toes and heels (i.e. toes-toes, heel-heel, toes-toes, and so on).
Step 2: Repeat 20 times (or more!).
Step 3: If you can find the time, stand up. March in place or take a brief walk around your office at a quick pace, raising your knees higher than you normally would for walking.
Marching, like any low-impact aerobic exercise, helps to increase your blood flow and your heart rate.