High-Intensity Interval Training (HIIT) is a popular form of interval training that alternates between short bursts of High-Intensity with periods of Low-Intensity active rest periods. The high-intensity and low-intensity intervals can range anywhere from 10 seconds to 4 minutes long. Shorter high-intensity interval ranges (10-30 seconds) engage the anaerobic system for energy. Longer high-intensity interval ranges ranges (more than 30 seconds) will engage the aerobic system for energy. Generally, a HIIT workout (including warm-up and cool-down) can be completed within 45 minutes based upon the intensity of the workout.

HIIT workouts have gained popularity due to their ability to provide similar health benefits to steady-state moderate intensity exercise in much less time.

Research shows that HIIT is more efficient than steady-state moderate intensity exercise at improving aerobic and anaerobic fitness, cardiovascular health, resting blood pressure, fat burning both during and after exercise, muscle mass, and cholesterol levels. One study showed that three days of HIIT per week for two weeks doubled the aerobic capacity of participants from 25 minutes to 51 minutes in a time trial. Another study showed that HIIT provided 100% of the benefits of endurance training despite only 10% of the total exercise volume. HIIT takes less time than traditional endurance training and can provide more health benefits. Thus, HIIT is an efficient and effective workout for people who don’t have time to spend an hour at the gym.

Generally yes, but this will depend on your own fitness level and circumstances. If an aerobic endurance base is developed over time and the training protocols are followed properly, then HIIT can be a safe and effective method of exercise. Individuals who are just starting to workout or have serious heart conditions should get the approval of their doctor before beginning strenuous activity. HIIT should not be the only form of exercise that you do during the week, but it can help you when you are crunched for time and need to workout quickly. 

Research shows that HIIT improves aerobic and anaerobic fitness, cardiovascular health, increases fat oxidation, maintains muscle mass, improves blood pressure, and improves cholesterol levels. And you don’t need to spend one hour on the treadmill or complete a complicated routine of 20 different bodyweight exercises in order to have an intense workout.

There are two components of losing weight, they are diet and exercise.  Losing weight requires you to be in a calorie deficit and diet and exercise will help you achieve this.  If you go on a 2-hour run, you will probably burn more calories than completing a 20-minute HIIT session, however if you are short of time, then a HIIT session will provide you with the best results.  A combination of HIIT and correct diet will be very effective at helping you lose weight rather than exercise or diet in isolation.

We would not recommend trying to do HIIT more than once per day for an average individual. The purpose of a HIIT workout is to give 100% effort during the workout and then allow proper time for recovery (ranging from 24-48 hours depending on your fitness level). A second HIIT workout would not be as efficient or effective as your first workout and can lead to injury if you are over-exhausting yourself. Instead of two HIIT workouts, you can add power walking or low-intensity cardio later in the day for active recovery. You don’t need to constantly give maximal effort to get the benefits of HIIT.

The answer to this question depends on the age, fitness level, gender and other factors for each individual. You should aim to increase the intensity of your exercise to get your heart rate up to 80-95% of your heart rate maximum (HRmax) during your working intervals. You should then decrease the intensity to bring your heart rate back down to around 60-75% HRmax during your active rest intervals. One way to estimate your HRmax is to take 220 and subtract your age (i.e. a 25-year old has an HRmax of 195). 

Here is a chart from the American College of Sports Medicine that will help you differentiate between your own high-intensity and low-intensity intervals. The chart also provides information relating to the Rate of Perceived Exertion (RPE) which is a subjective measure of how difficult the workout feels for you.

Intensity

HRmax

RPE

Low (i.e. Walking)

57-63%

Very light to fairly light

Moderate (i.e. ET)

64-76%

Fairly light to somewhat hard

Vigorous (i.e. HIIT)

77-95%

Somewhat hard to very hard

All-Out (i.e. Sprinting)

>95%

Very hard

No, not at all.  We use the MyZone heart rate monitoring system to ensure you are at your correct intensity throughout the workout.  Our coaches keep a close ye on you and not just the intensity or exercise technique.  Whilst your Coach is there to encourage you to push yourself so you always get better, they are not there to hurt you!

Members book into classes online 24/7 via our website.  However if you are not a member you need and wish to trial a class, then simply email us at [email protected] and we will be able to organise for you to attend a class as a trial at no cost.  

If you aim for 2-3 sessions a week you should start to see a difference in about 3-4 weeks.  Please remember to maintain an appropriate diet during the same period to ensure results are not slowed by incorrect eating.

Yes, you must book a spot in a class prior to attending.  The purpose of this is to ensure the Coach sets up the room correctly for the amount of participants.  You can book via the hiit republic website at https://www.hiitrepublic.com.au/ and selecting the Timetable option.