If you want to burn calories while doing computer work, using a treadmill desk is a surefire way to do so. LifeSpan, a fitness company that primarily makes workout machines, has created a 68.5 by 28.5-inch treadmill attached to a 38 by 29-inch desktop. You can adjust the height of the desk between 52.5 and 32.5 inches to suit your height. The treadmill console tells you your distance traveled, calories burned, step count, and speed. Compared to average treadmills, this motor is extremely quiet and usable in a public environment. Sync your treadmill desk with the LifeSpan app on your smartphone to keep up with your stats.