You've probably heard the term 'high intensity interval training' being thrown around the fitness world and might be wondering "Why is everyone raving about HIIT, what makes it so good, and why should I care?". We're going to answer these questions and more; if you haven't heard of HIIT, don't worry, we're going to give you an overview on the following:
- What is HIIT?
- Why is HIIT such so effective?
- What are the benefits of HIIT?
- How to do HIIT for fat loss or weight loss
- Example HIIT routines you can use at home or at the gym
Let's dive in!
What is High Intensity Interval Training?
More commonly referred to by the abbreviation, HIIT, is a style of cardio training that alternates between periods of maximum intensity and rest.
This style of training became popular due to the number of scientific studies demonstrating it's superior ability to drive fat loss compared to steady-state cardio training such as running.
In fact, when compared to steady state cardio training, HIIT has been scientifically proven to achieve similar results with 40% less time committed.
Additionally, a 10-week HIIT program can reduce overall body fat by as much as 10% while the 12-week HIIT treadmill program in the same study observed a 19.5% decrease in abdominal visceral fat (belly fat).
What are the benefits of HIIT?
We'll discuss the in's and out's of how HIIT actually works in the next section but for now let's summarise the benefits of high intensity interval training:
- Lowering blood sugar
- Reducing risk of heart disease
- Improving the body's natural fat burning ability
- Reducing risk of Type II diabetes
- Improving muscle development
- Improving exercise capacity
How does High Intensity Interval Training work?
There are several mechanisms that enable high intensity interval training to provide effective fat loss while also minimising muscle loss. These include:- Increased fatty acid transport
- Excess Post-Exercise Oxygen Consumption (EPOC)
- Improved insulin sensitivity
- Hormonal response
Increased fatty acid transport
The mechanism of fatty acid transport is complex however in simple terms you and I can understand, it refers to the uptake of fatty acids by your body and is the critical mechanism your body uses to burn fat.
Researchers from the Department of Medicine at McMaster University in Canada found that HIIT training can increase fatty acid transport by 14-30%.
Excess Post-Exercise Oxygen Consumption
Similar to how a car’s engine remains warm after being turned off, once a workout is over, your body’s metabolism can continue to burn more calories than it would under resting conditions. This physiological effect is called excess post-exercise oxygen consumption (EPOC) or oxygen debt.
EPOC is the amount of oxygen required to restore your body to its normal, resting level of metabolic function (called homeostasis). It also explains how your body can continue to burn calories long after you’ve finished your workout.
In fact, the effect of EPOC can be attributed to as much as 15 percent of the total energy burned during the exercise session!
Improved insulin sensitivity
High intensity interval training has been shown to achieve maximal fat oxidation rates (fat burning) in men and women that are overweight and suffering from Class I and Class II obesity.
This shows that HIIT exercise training is more effective at improving insulin sensitivity and reducing the risk of Type II diabetes than moderate cardio training.
Hormonal response
Scientific studies have found that exercise-related hormonal responses, including cortisol and growth hormone, were significantly higher following HIIT workouts compared to moderate cardio workouts.
Cortisol is a key hormone which helps manage how your body uses carbohydrates, fats and proteins, as well as helping regulate blood pressure, blood sugar and providing energy boosts to your body.
Growth hormone has a myriad of uses and benefits, such as increasing muscle mass, improving exercise capacity and reducing risk of heart disease.
The Three Most Important Aspects of HIIT That Will Maximise Fat Loss
Many people have a general idea of what high intensity interval training is, very few people actually implement HIIT training in a way that will maximise it's effectiveness.
What type of HIIT is most effective?
The versatility of HIIT training allows you to take almost any form of cardio exercise and create a HIIT routine. However, you should stick the the three most effective variations which include:
- Sprinting
- Rowing
- Cycling
Why these three?
The more a cardio exercise mimics the movements used in muscle-building movements, the less it hinders strength and growth. These three exercises closely mimic major compound movements such as squats, deadlifts and seated rows and are therefore most likely to help maintain muscle strength.
What level of intensity do I need to achieve?
Workout intensity is the most important factor (no surprises there!) with regard to high intensity interval training. Unfortunately people continue to get this fundamental aspect wrong!
The primary difference between high and low intensity training should be your speed and not the amount of resistance used. So when you're cycling, you want to place most of your focus on increasing your speed rather than the level of resistance you're working at.
It's also critically important to work in the correct heart rate range to maximise the benefits of HIIT training. Keeping your pulse between 85-95 percent of your maximum heart rate during the high intensity work intervals has been scientifically proven to maximise results and fat loss.
How can you tell if you're at the right level of intensity?
An easy way to give yourself a rough idea of whether you're at the right intensity is when you reach the point where you can't comfortable hold a conversation because you're breathing so heavily.
I know it sounds funny, but this is where you want to be; the goal of HIIT is to maintain this intensity for as long as possible during the high-intensity intervals over repeated cycles.
The higher the intensity and the longer the intervals at that intensity, the more effective your HIIT workout will be.
A good rule of thumb to help ensure you get the most our of your HIIT session, particularly as a beginner, is to start at 80% of your maximum intensity with a work ratio of 1:2. This means you sprint at 80% of your maximum effort for 20 seconds, followed by a 40 second active rest period (walking).
How to set yourself up for success
- 80% maximum effort during work intervals
- Use a work ratio of 1:2, for example 20 seconds sprint and 40 seconds walking
Using progressive overloading to maximise results
As you progress in your HIIT training, your body will adapt and eventually reach a fat loss plateau. At this point, the best way to continue towards your fat-burning goals is through the use of progressive overloading.
Progressive overloading is a strategy used among many sport professionals to break through natural performance plateaus and achieve further results.
We can use this technique in the same way to break through fat loss plateaus where your body adapts to your exercise and you stop seeing progress.
Progressive overloading can be achieved by:
- Increasing the intensity of your work intervals
- Increasing the duration of your work intervals
- Decreasing the duration of your rest intervals
- Increasing the total number of cycles and intervals you complete
- Increasing the frequency of your HIIT workouts
High Intensity Interval Training Workouts and Routines
Pulling the above information together into an effective HIIT workout for maximum fat loss, we've compiled a selection of HIIT routines below for you to explore.
HIIT Workout Routine for Fat Loss
Week 1 & 2
- Frequency - One session/week
- Work Interval - 20 seconds of 80% max intensity cycling
- Rest Interval - 40 seconds of light cycling
- Number of Intervals - 5 cycles
Week 3 & 4
- Frequency - Two sessions/week
- Work Interval - 20 seconds of 80% max intensity cycling
- Rest Interval - 40 seconds of light cycling
- Number of Intervals - 5 cycles
Week 5 & 6
- Frequency - Two sessions/week
- Work Interval - 30 seconds of 80% max intensity cycling
- Rest Interval - 30 seconds of light cycling
- Number of Intervals - 7 cycles
Week 7 & 8
- Frequency - Three sessions/week
- Work Interval - 40 seconds of 80% max intensity cycling
- Rest Interval - 20 seconds of light cycling
- Number of Intervals - 7 cycles
HIIT Treadmill Workout Routine
The great benefit of performing a HIIT workout on a treadmill is the ability to set your pace on the machine and force yourself to meet your target (no cutting corners!).
If you're looking for a quick yet effective 20 minute HIIT workout that you can do on a treadmill, either at home or in the gym, then give this a go.
- Warm Up - 5 minutes brisk walking
- Frequency - Two sessions/week
- Work Interval - 30 seconds sprint at 11 - 15 km/h with incline set between 0.5 - 3 depending on your fitness level.
- Rest interval - 40 seconds of walking
- Number of intervals - 5 cycles
Don't forget to use the progressive overload strategy we discussed previously to enhance your workouts and boost your results over the long-term!
HIIT Body Weight Workout Routine
- Warm Up - 5 minutes brisk walking
- Frequency - Two sessions/week
- Work Interval - 30 seconds max effort
- Rest Interval - 30 seconds walking
- Number of Intervals - 7 exercises
For this routine we'll be performing a range of exercises designed to target and engage the whole body:
- 180 Jump Squats
- Five Foot Shuffles
- One Arm Burpees
- Spider Luge With Knee Drive
- Power Thrusters
- Knee Drive Mountain Climbers
- Lateral Lunge With Knee Drive
These will help improve overall muscle fitness as well as push your body to the optimal level of effort to maximise results. Let's take a look at how to perform each movement.
180 Jump Squats
Squat down and tap the ground. Launch up, jump and spin 180 degrees. Repeat. (Beginners - Stand up and spin).
Five Foot Shuffle
Quickly sidestep (shuffle) left for five steps and touch the ground. Repeat to the right and touch the ground. Repeat.
One Arm Burpees
As a regular burpee but with only one hand touching the ground. Start in a prone position on your toes and hand with back, legs and arm straight.
Jump your legs into a tuck under you and then jump upwards, raising your hand over your head. Return to prone position and repeat with alternate hand. (Beginners - Regular burpees; stand up instead of jump if you struggle)
Spider Lunge with Knee Drive
Start in a prone position on your toes and hand with back, legs and arm straight.
Bring legs underneath you in a tuck and stand up. As you stand, bring one knee up driving as high as you can.
Return to prone position and repeat with alternate knee.
Power Thrusters
Start in a prone position on your toes and hand with back, legs and arm straight.
Perform a push up, chest to the ground with legs and torso straight. As you extend your arms to maximum, jump up into a crouch position. (Beginners - step into the crouch position, knees on the ground if needed).
Knee Driver Mountain Climbers
Start in a prone position on your toes and hand with back, legs and arm straight.
Alternating legs, pick one foot off the ground and drive the knee forward fast and hard as you can. Keep your other leg straight, back flat and maintain your prone position.
Alternate legs and repeat.
Lateral Lunge With Knee Drive
Start standing. Keeping your right foot stationary, step left leg to the side and squat into a side lunge touching the ground with your fingers.
Drive back up to standing, raising your left knee to your chest as you do so. Repeat for two reps then alternate legs. Repeat.
HIIT Rowing Workout Routine
- Warm Up - 5 minutes light rowing
- Frequency - Two sessions/week
- Work Interval - 30 seconds max effort
- Rest Interval - 90 seconds of light rowing
- Number of Intervals - 8 cycles
Start with your warm up on a resistance level of around 5. Make sure to use correct technique and full range of motion:
- Drive with the legs first, keeping arms straight.
- Once legs are extended, hinge with your hips and lean back. Keep your back straight and strong!
- As you lean back, bring your arms in to complete the movement.
For your high intensity intervals, keep your resistance the same and push for maximum effort.
