Treadmills allow you to get an HIIT workout no matter the weather.
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A high-intensity interval training, or HIIT, workout is a fast-paced way to perform your treadmill exercise, and it burns a lot of calories. This type of workout not only burns the same or more calories than moderate intensity exercise of the same duration, but also elicits a beneficial after-burn effect called excess post-oxygen consumption, or EPOC, causing your body to continue burning calories at a faster-than-normal rate for hours after the workout is done.
Prime the Pump
Using your treadmill, you can do an HIIT workout several different ways. HIIT works by alternating short high-energy intervals with recovery intervals done at a light to moderate pace. You can try various combinations of fast and slow intervals, but get started by trying 20 seconds fast and 40 seconds slow; repeat this 60-second cycle for 20 to 30 minutes. Adjust times accordingly once you get the hang of it.
One way to go about this is to use a sprint-and-jog HIIT regimen. If you're more of a walker, you can alternative short walk intervals done at 4 mph or more - as fast as you can go - with slower intervals performed at about 2 or 3 mph. A third way to do go about your HIIT workout is to use your treadmill's incline settings to boost the workload. Obviously, you'll burn the most calories by exercising at the highest intensity possible, meaning the sprint-jog workout and the incline workout will burn the most calories.
Compare the Burn
If a 200-pound person were to jog at 5 mph at a steady pace for 30 minutes on the treadmill, he would burn about 384 calories. The same person would burn approximately the same number of calories in 30 minutes doing an HIIT workout consisting of a 50/50 ratio of 7 mph sprints and 3 mph walking for recovery - an average of 5 mph, but then burn an average of 58 extra calories after the workout.
The difference occurs in the EPOC after-burn effect associated with HIIT. It's difficult to estimate exact figures because it varies from person to person, but you can expect to burn an extra 15 percent more calories following HIIT workouts, or in per the example above, nearly 58 calories. The after-burn effect of burning calories faster than you would at normal resting state can last up to 24 hours after the workout is done.
Burn more on the Treadmill
Increase the treadmill's speed, incline or both to burn more calories during your HIIT workouts. As an example of how this works, jogging at 6 mph on a flat deck burns about 2 calories per minute, while walking at just 2 mph on a 16 percent incline burns about 6 calories per minute. Since walking on an incline is less stressful on your joints compared to jogging on a flat-deck treadmill, alternating walking on a flat deck with walking at a steep incline for your HIIT workout may be an optimal choice if you have joint pain or physically can't do an all-out sprint workout on the treadmill. It's an effective way to burn a significant number of calories without resorting to sprinting or even jogging on the treadmill.
Freak Out Your Hormones
HIIT is the most effective way to promote long-term improvements in fat loss and overall body composition. You have to look beyond the number of calories burned to see just how this works. High-energy exercise causes a physiological response in your body that basically makes your hormones go berserk. HIIT causes an increase in human growth hormone, testosterone, endorphins and other hormones in your body. Additionally, the high-intensity nature of the workout increases the size and number of mitochondria in your body, which is the tiny energy factories at the cellular level. This combination benefits your body by increasing your VO2 max - your overall aerobic capacity - burning more calories and body fat, and increases your heart health better than steady-state moderate exercise of the same duration.