What is HiiT?
HiiT stands for High-Intensity Interval Training and involves alternating periods of high-intensity exercise with periods of rest and recovery. For example, in my HiiT Quickie Workouts we do 3 rounds of 5 exercises for 50 seconds on, 10 seconds rest.
HiiT workouts are designed to improve cardiovascular capacity and conditioning, which in turn improves glucose metabolism (how your body produces energy) and fat burning.
Research also shows that short HiiT workouts can be just as or more effective than longer, steady-state cardio because of the EPOC effect.
What is EPOC?
Also known as the afterburn effect, EPOC stands for Excess Post-Exercise Oxygen Consumption. Simply put, this is the amount of oxygen your body requires after exercise to return to its resting state and adapt to the work you just did.
EPOC matters because it means you’ve pushed your body to the point of having an oxygen debt. If you sprint up a steep hill as fast as you can, it will be quite difficult to catch your breath afterward, right? That is EPOC in action. Your body is now forced to work harder to return to normal, and all the while you’re expending more energy.
The good news – that means you’re burning calories even after you’ve stopped exercising! Brilliant!
Interestingly enough, you may burn fewer calories during a HiiT workout (as compared to a steady-state workout like jogging), but you’ll burn far more calories after the workout. According to one study, for up to 38 hours afterward!
Most forms of exercise will generate an afterburn effect to some degree, but not all forms are equal. After lower intensity exercise, your body’s systems don’t take as long to return to normal. Therefore, you expend less energy while recovering. But with higher intensity exercise, more energy is needed afterward to catch your breath, return hormone levels to normal, and oxidize the build-up of lactic acid in your muscles. HiiT makes brilliant use of the afterburn.
Who Should Do HiiT?
HiiT is adaptable to all levels because high-intensity is relative. Let’s use burpees as the example exercise.
A very fit person might do 16 burpees in 45 seconds and trigger a major afterburn.
A less conditioned person may only manage 7 burpees in 45 seconds, and yet that person will still be out of breath and very challenged, hence triggering a major afterburn.
And a beginner may trigger the afterburn by doing 45 seconds of squats, which would be a good alternative to the more advanced burpees.
Will HiiT Help Me Lose Fat?
Yes! The afterburn effect can last anywhere from 15 minutes to a full 48 hours! That means you’re expending additional energy for many hours after your workout is done. This is a great benefit to those trying to lose weight! Steady cardio for long periods of time will burn fat. BUT, they take up a longer period of time and unless you incorporate higher-intensity intervals, your metabolism may return to normal more quickly so you get less benefit from the afterburn effect. Higher intensity cardio, like you get with my Quickie HiiT Workouts, will force your body to work harder afterward. That’s where the magic happens.
Will HiiT Help Me Build Muscle?
Yes! In addition to cardio-based moves like sprinting and jumping jacks, it makes sense to incorporate exercises to build power and strength using weights and other forms of resistance. These moves build muscle tone, speed, and power. You don’t have to separate your weight training routines from your long cardio sessions. You can get it all with HiiT workouts! And in far less time.
Building muscle actually helps you burn fat as well, because muscle cells are more metabolically active than fat cells. Your metabolism has to work harder to supply your muscle tissue with the nutrients they need. The harder your body works to provide those nutrients, the more energy you expend. Expended energy = calories burned.
How Long are HiiT Intervals?
With HiiT, like in my Quickie Workouts, exercises are performed at a very high intensity for a specific amount of time, followed by a brief rest period, and then those intervals are repeated several times. The ratio of exercise to rest can be adapted to your fitness level.
For beginners, I’d recommend starting with 30/30 intervals – 30 seconds of exercise followed by 30 seconds of rest.
Then, I’d advance to 40/20 intervals.
Advanced might tackle 50/10 intervals.
I use 50/10 timing in my Quickie Workouts, and if you follow along with those, simply go as long as you can during the 50 seconds, and rest when needed. There’s no shame in needing a longer rest period in the beginning. Because every exercise is challenging and you’re asked to give it your all, these workouts are sure to be challenging!
If my Quickie Workouts are too hard for you, learn ways to make my Quickies easier here.
If you are truly going all-out during the work portion of the interval, whether you do 20 seconds or 1 minute, it will be challenging!
And if you are new to HiiT training, you are in for a treat! A treat in the form of decreased fat, sculpted muscles, and an overall increase in awesomeness!
Have you tried HiiT training yet? If so, what are your favorite exercises to include?