Read on to learn more about High Intensity Interval Training, and whether it’s right for you.
Getting bored with your cardio routine? Trying to push through a weight loss plateau or get a little leaner to show off those hard-earned muscles? Maybe you’re looking for a more efficient way to make the most out of a time-crunched workout? High intensity interval training (referred to as “HIIT”) just might be the answer you’ve been looking for.
How is HIIT different?
In a nutshell, a HIIT workout alternates between short intervals of maximum intensity and longer intervals of moderate intensity. Yes, you’ve probably seen the generic interval modes on cardio machines and may even have tried them out—this is different. The standard interval training you’ve done before simply involves alternating lower heart rate exercise with higher heart rate exercise. HIIT, however, is distinguished by the fact that the high intervals are done at maximum intensity—not merely an elevated intensity.
What are the benefits of HIIT?
Because HIIT incorporates maximum intensity effort, it conditions both the aerobic and anaerobic systems. This will lead to an increase in your VO2 max, which is the maximum amount of oxygen you can take in while exercising. In other words, your overall cardio endurance will improve. Also, research has shown that, due to the amount of time it takes your body to recover after a HIIT session, the number of calories burned both during and after a 20-minute HIIT session can equal or even far outweigh the number burned during and after a steady 50-minute cardio session. Finally, research has also demonstrated that HIIT sessions appear to be an effective means of reducing body fat while still preserving muscle mass—as opposed to long, steady cardio sessions which can deplete muscle stores.
How do I do a HIIT workout?
Imagine your personal scale of exertion, ranging from 1 to 10. Let’s say a 1 represents the energy it takes to roll over in bed, while a 10 would be something like running for your life from a zombie, flying cockroach, etc… Keeping that in mind, start your cardio workout with a 5-minute warm up. The duration of intervals used for a HIIT session can vary, but this basic principle always applies: after the warm up, start alternating between an interval at a 9 and an interval at a 6 (based on that 1-10 scale mentioned above). A good place to start is 30-second intervals at a 9, and 90 second intervals at a 6. 30 seconds may not sound like much, but if you are really working at a 9, it will feel like the longest 30 seconds of your life. As you get the hang of HIIT workouts, you can vary your intervals (20 seconds at a 9, 40 seconds at a 6, etc…). Because these workouts are intense, you shouldn’t do them more than 2 to 3 times per week. Also, they are not meant to fully replace longer cardio sessions, especially if your goal is fat loss. For example, you may want to start with 2 days of HIIT per week, but alternate them with 2 days per week of traditional steady-state cardio exercise.
Who should use HIIT?
Because HIIT workouts are physically demanding, they are not for everyone. If you are new to exercising, are not already in moderately good shape, or have any cardiovascular or health concerns that could be affected by intense aerobic effort, you should not try HIIT without first consulting your doctor. If, however, you are already capable of completing a 20 minute workout at roughly 75% of your estimated maximum heart rate, you should be ready to give HIIT a try.
 Physiological adaptations to low-volume, high-intensity interval training in health and disease, The Journal of Physiology, 2012 Mar 1; 590 (Pt 5): 1077-84.