Changing your direction is another great way to mix up your cardio workouts for better results. If you always move forward on the treadmill, elliptical, or bike, try moving sideways and backwards too, Olson says.
"We are so used to moving forward in one plane of motion, but research on treadmill exercise has shown that you can burn more calories and activate lesser-used muscles such as your outer hip muscles, shins, and hamstrings if you turn your walk or jog sideways and backwards."
Try this routine: Walk or jog for 3 minutes forward, and then turn to the side and do a side shuffle for 30 seconds with your right leg leading, and then turn around and lead with your left leg for 30 seconds. Return to your forward stride for 3 more minutes, and then try walking backwards for 30 seconds. For safety, be sure to slow your speed and/or use the handrails as you adjust to moving in new directions.
"Since your body is not used to this (even though it is designed to move in all three directions), it will pump your heart rate up higher and cause you to burn extra calories." You can also do this on the elliptical or stationary bike. Use the interval routine above but simply pedal backwards for the 30-second intervals.