When it comes to shedding fat, you have to grind away hour upon hour on the elliptical, right? Wrong! Research shows there is a superior form of cardio training for achieving your best possible physique – high intensity interval training (HIIT).
HIIT is a workout regimen in which you alternate periods of (near) all-out and low effort. An example is sprinting on an exercise bike for 30 seconds followed by 30 seconds of rest. Such style of training can help you burn up to nine times as much fat as traditional cardio .
But this way of training is not just superior for ditching that spare tire you carry: scientists have found that HIIT beats steady-state cardio when it comes to improving endurance. In fact, where advanced trainees are concerned, some researchers believe HIIT is the only way to keep improving certain endurance markers .
But what exactly is HIIT? And should you add it to your workout program? That, and more, you’re about to discover. Read on, learn, and put in practice!
What Is HIIT?
While there is no universal definition of the term, “HIIT” generally refers to a style of exercising in which you alternate periods of (near) all-out and low effort. An example is doing sprints on an exercise bike for 30 seconds followed by 30 seconds of rest. Such training style allows you to exert your body to a greater degree compared to traditional steady-state cardio.
While the popularity of HIIT is steadily rising, it is not something new. HIIT has been used for almost a decade now by endurance athletes to improve their condition. Paavo Nurmi, one of the world’s best middle- and long-distance runners around 1920, was already using elements of HIIT in his training routine.
But HIIT is not suited only for elite endurance athletes. It can be used for many purposes, ranging from fat loss to improving brain function to stimulating cardiovascular disease rehab [1-5].
HIIT Is Superior for Losing Fat
When it comes to losing fat, most people believe they must suffer endless hours of steady-state cardio. Nothing can be further from the truth! Research clearly shows that HIIT is superior for fat loss [1-2].
A study by the Laval University (Quebec), for example, had 27 individuals follow either a 20-week steady-state cardio program or a 15-week HIIT program consisting of 10 to 15 sprints of 15 to 30 seconds. At the end of the study, the results that emerged were remarkable.
Despite the fact that their program was 5 weeks shorter, the HIIT group lost nine times as much fat and 12% more visceral belly fat than the steady-state cardio group .
Coincidence? Definitely not! Research by the University of Western Ontario (London) found similar results. The scientists noted that just four to six 30-second all-out sprints burned more fat than 30 to 60 minutes of incline treadmill walking .
The Best HIIT Workout for Fat Loss
To turbocharge fat loss with HIIT workouts, there are two things you should keep in mind.
First off, set up your work and rest intervals in such a way that you maximize the release of lactic acid. This, in turn, causes the secretion of HGH, a powerful fat-burning hormone 
To ensure maximum lactic acid build-up, a great work-rest interval pattern is going (nearly) all-out for 30 to 45 seconds and then resting for 30 to 45 seconds. Do this for a total of 6 to 12 sets.
Second, you have to choose the right exercises. They should strain many muscle groups at once, and you must be able to perform them safely under high levels of fatigue. Two excellent options are sprints on an exercise bike and sprints on a rowing machine.
Here is a sample fat loss HIIT workout:
Exercise: Sprints on exercise bike
Work interval intensity: 90% of maximum sprinting speed
Work interval duration: 30 seconds
Rest interval duration: 30 seconds
Rest interval intensity: Very slowly pedaling (10% of max speed)
Total sets: 10
Why HIIT Is Superior for Improving Endurance
Not only is HIIT the best form of cardio to lose fat, it is also the superior choice for improving endurance, especially if you’re an advanced endurance athlete. Why? Because when submaximal endurance training (steady-state cardio) becomes habitual, additional increases in the training volume (training longer) or the training frequency do not further improve performance . In other words, you’ll get to a point of diminishing returns.
That’s why researchers believe that the only way for highly trained endurance athletes to keep improving is by adding HIIT to their workout routine .
But this applies not only to high-level endurance athletes. HIIT is also the go-to way to build endurance at beginner and immediate levels. Scientists from the University of Queensland (Australia) concluded: “HIIT in sedentary and recreationally active individuals improves endurance performance to a greater extent than does continuous submaximal training alone” .
So, why is HIIT superior for improving endurance performance markers? It’s been suggested the reason is that HIIT stresses the oxygen transport and utilization systems to an extent impossible with steady-state cardio [9-10].
Now, don’t interpret this wrongly. If you want to take part in a marathon, you have to specifically prepare yourself for the event, meaning you have to run over long distances. But adding HIIT on top of that will give you an edge and allow you to maximize your performance.
The Best HIIT Workout for Improving Endurance
To improve your endurance with HIIT training, you must build your HIIT sessions with one goal in sight: creating the largest oxygen deficit possible. In order words, train in such a way that you’ll be completely out of breath, gasping for air. This stresses your oxygen transport and utilization systems to the max, leading to the greatest improvement in Vo2max and other endurance markers.
An example is Tabata training – a HIIT program in which you alternate between 20 seconds of all-out effort (on an exercise bike) and 10 seconds of rest over a total of 8 rounds, or 4 minutes all told. When done right, this is extremely tough, but the results are worth it.
This form of exercising is extremely taxing, both psychologically and on your cardiovascular system. So, when you do it right, you can’t maintain such training style for longer than 5 to 10 minutes. (And that shouldn’t be your goal!)
When using HIIT to improve endurance, you must focus on quality, not quantity. Every set must be done at a maximum intensity, and the rest periods between sets must be kept to a minimum. Besides, you must choose exercises that stimulate many muscles at the same time, such as sprints on an exercise bike.
What’s the Bottom Line on HIIT?
Whether you want to lose fat or improve your endurance, research on the subject speaks clearly – HIIT is your ticket to success. The downside? When done right, HIIT training is extremely tough. It has you gasping for air and makes you doubt the benefit of putting yourself through all this torture. But don’t let that stop you – the results are worth it! So no more excuses, put your nose to the grindstone and start HIIT’ing it!
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