In recent times, High intensity interval training (HIIT) seems to be an increasingly popular buzzword. Many now pair this with restricted eating windows, intermittent fasting, which together have a compounding effect on weight loss. But, let’s not get ahead of ourselves. Today we’re focusing on HIIT.
When we think of weight loss, we think of diet. Although diets are important, exercise is just as important for promoting, maintaining weight loss and building muscle. It's well know that cardio is the best exercise for weight loss and HIIT is the best type of cardio. High intensity interval training is a cardio technique many athletes use that’s actually proven to work. There’s a lot more to it than just sweating and panting. It's simply one of the most efficient ways to burn fat, get in shape, and improve overall health.
But what exactly is HIIT? How does it work and what are some of its benefits? Let’s looks at these questions in a little more detail.
What is Hight Intensity Interval Training (HIIT)?
As the name implies, HIIT involves:
- High Intensity - The cornerstone of HIIT, short bursts of very intense exercise.
- Intervals - Between these periods of intense exercise are low-intensity recovery periods.
In other words, a HIIT would typically involve short periods of intense exercise alternated with low-intensity recovery periods. For example, a HIIT workout using sprints could include 30-second sprints alternated with 2 minute jogging periods. Every completed cycle is then a repetition of HIIT.
Why Is HIIT Effective for Burning Fat?
All forms of cardiovascular exercise burn fat. You’ll notice, most cardio machines have flashy dashboards that show the fat-burning zone, which is typically at lower heart rates. The idea behind that is, at a lower intensity steady-state cardio, the body can rely mostly on fat stores for energy. At higher heart rates, our bodies need a more efficient source of energy so it switches to glycogen (sugar) stored in our stomach (food we recently ate), muscles and organs.
This is why most machines view low intensity steady-state heart rate as a fat burning zone. But, if HIIT is more intense than steady-state cardio, how can it be more effective for burning fat?
Well, it starts with calories. In simple terms, the more calories someone burns, the more fat they’ll lose. Keep in mind that the body doesn't always burn just fat or just glycogen. It's about the proportion. At lower intensities, it may burn 70% fat and 30% glycogen. At higher intensities, it may switch to burning 90% glycogen and 10% fat.
And HIIT surely burns a lot of calories.
A 2015 study compared the calories burned during 30 minutes of steady-state cardio, weight training, and HIIT. The steady-state cardio comprised of biking and cycling while the HIIT consisted of 20 seconds of maximal effort, followed by 40 seconds of rest.
And the results were surprising. The researchers found that HIIT burned 25 - 30% more calories than the other forms of exercise. The results showed, for example, running burned 284 calories in the 30 minutes while the HIIT regimen burned 378.
This means that HIIT may burn a lower proportion of fat, it burns more calories that, over time, will burn more fat and lead to fat loss.
But that only paints half the picture. HIIT is also shown to:
- Increase metabolic rate for 24 hours after a workout.
- Reduce insulin resistance.
- Increase fat oxidation in muscles.
- Increase growth hormone and catecholamine levels
- Suppress appetite.
All these increases the amount of fat burned and makes HIIT the perfect tool to burn as much fat in as little time as possible. Also, apart from the obvious weight loss benefits, it may build muscle, improve oxygen consumption, reduce heart rate and blood pressure, and reduce blood sugar.
What Exercises Are Best for HIIT?
A simple search on the best HIIT exercise will return many workout plans that incorporate anything from squats, machine bench presses, and kettlebell swings. Although these could be used, the fact is that HIIT is cardio and should be treated like cardio.
Thus, the best exercises for HIIT are cardio exercises. Now, this could be any form of cardio, but some are more effective than others.
For this reason, it's best to stick to:
An example workout using sprints would be to sprint for 30 seconds and walk or jog for 2 minutes and repeat this cycle 8 times. In other words:
- Warm up for 5 minutes
- Sprint for 30 seconds
- Jog for 2 minutes
- Repeat 8 times
- Cool down for 5 minutes
Keep in mind, though, that this is not a hard and fast rule, and HIIT principles can be applied to any form of cardio like swimming, calisthenics, boxing, and so on. The most important thing to remember is to take the high-intensity intervals to the max while going very easy on the rest intervals.
How Intense Should HIIT Workouts Be?
With HIIT workouts, intensity is vital. This means upping the intensity of the cardio and pushing it to the max with every repetition. Not doing so just makes it a harder cardio workout and not true HIIT.
And that's why the repetitions are short. Spending too much time training at this intensity will lead to burnout. Likewise, the recovery periods should be low intensity. If the intensity is too high, it isn't a true HIIT workout and can increase the possibility of burnout.
Over time, as fitness improves, it may be necessary to increase intensity. This can be done by either lengthening the high-intensity intervals or shortening the rest periods.
How Long Should HIIT Workouts Be?
Because HIIT is so efficient and gives a lot of benefits in very little time, it's simply not necessary to do it for hours on end. Besides, it's very stressful on the body, so it's easy to overdo, which can lead to burnout or injuries.
The general consensus is that between 20 and 30 minutes is enough, with 60 minutes being the absolute maximum.
How Frequent Should HIIT Workouts Be?
Once again, the intensity of HIIT plays a role in the frequency of the workouts. Because of the toll it takes, two to three HIIT workouts a week is enough as long as there are at least 24 hours of rest between the workouts.
This gives the body time to recover from the stresses of a HIIT workout and prevents injuries and burnout.
There it is, all the information to get started with HIIT. So, go ahead, try it, and let us know on Facebook how it works for you!