Feel the HIIT: The Basics of High-Intensity Interval Training

High-intensity interval training or “HIIT” continues to shine in the fitness industry, with many gyms and fitness businesses thriving on the interest and popularity of this training style throughout the years. What’s the hype, and how does it work? Let’s talk about HIIT.

While HIIT training is relatively new in the fitness industry, athletes have been employing this style of training since the early 90s [5]. Olympian, Emil Zátopek, won gold in a 5000m race in the 1952 Helsinki Summer Olympics, crediting his win to HIIT being part of his training regime [5]. But wait there’s more… Emil continued his gold streak in the 10,000m event and the marathon. Not only was this his first-ever marathon, it was also one he entered at the last minute! And not only did he win, he also broke Olympic records in both of these events [2]… talk about winning!

Unsurprisingly, this led to growing interest in HIIT for athletes everywhere, including scientists who  turned towards how it worked. Today, HIIT is not only for the elite athlete – it’s likely your local gym runs an exercise class focussed on HIIT-style training, or is inspired by some of its principles. It is also likely you have done some HIIT yourself, or are participating in classes based on HIIT formats!

High-intensity interval training (HIIT) is a type of training that orders exercises performed at higher intensities in alternation with exercises at lower intensities or periods of rest… all within one training session. HIIT exercises can be cardiovascular-based, resistance (weight)-based or a combination of both. What types of exercise are incorporated would depend on individual fitness goals, but all operate on the HIIT format of alternating high-intensity exercises with low-intensity ones.

Within a HIIT session, you would execute ‘work intervals’ and ‘rest intervals’. HIIT works best on optimal work-to-rest ratios that correlate with one’s level of exercise experience. The less experienced someone is, or the lower their fitness levels are, the longer the rest intervals generally are. As the individual gets fitter, the work intervals can increase, rest intervals decrease or a mixture of the two [5].

For example:

• An advanced client in sprint training may execute 5 sets of 100m sprints in an EMOM (every minute on the minute) workout
• A beginner client in sprint training may execute 5 sets of 100m sprints in an E2MOM (every 2 minutes on the minute) workout

In the example above, our beginner client gets a 2-minute rest, while our advanced client gets a 1-minute rest.

Safety during exercise should be your number one priority in any training session, so modifications should always be considered in the context of your ability and exercise experience – HIIT is no exception to this rule. For beginners, we start at lower weights, distances or durations, allowing time for adaptation, enjoyment of the session and consistency in training. Over time, exercise intensity can increase as fitness levels grow.

HIIT is known to positively influence cardiovascular health by increasing one’s aerobic capacity [5,6]. Aerobic capacity is the body’s ability to use oxygen more efficiently and at higher intensities. A higher aerobic capacity assists in preventing cardiovascular disease and improving overall cardiovascular health**. 

For this reason alone, HIIT is beneficial to include in any exercise regime for improving overall fitness. 

• Time Efficiency: One of the biggest barriers to exercise is time or the lack of it. Due to the nature of HIIT-style training, this can overcome these barriers for individuals. HIIT workouts are typically shorter than traditional steady-state cardio workouts and can be done in as little as 20 minutes. This is great for people who have busy schedules and don’t have a lot of time to dedicate to exercise [3]. 

• Increased Metabolic Rate: HIIT workouts can increase your metabolic rate for hours after the workout is completed. This means you continue to burn calories even after you have finished exercising, which can help with weight loss and fat burning [1]. 

Other benefits include:

• Increased Endurance: HIIT workouts are designed to push you to your limits and then allow you to recover. Over time, this can help increase your endurance, allowing you to perform at a higher level for longer periods of time [7]. 

• Versatility: HIIT workouts can be done with a variety of exercises, including running, jumping, cycling, and resistance training. This means you can switch things up and keep your workouts interesting, which can help prevent boredom and keep you motivated and make exercise fun[8]. 

• Improved Muscle Physiology: HIIT workouts can help improve the function and structure of muscles by combining resistance training with high-intensity cardio. This type of exercise can help build lean muscle mass and increase overall strength [3]. 

Key Takeaways

When people think about HIIT training, they often misinterpret it as the use of all-out efforts. For those beginning an exercise routine, going “all-out” can be daunting and discouraging, leading some to believe they must ‘work up’ to HIIT or improve their fitness before attempting any HIIT program.

The truth is: HIIT is for everyone – you decide what ‘high intensity’ means for you, then set the bar challenging enough for the level of fitness you are at, increasing the bar as you become fitter.

This means that whatever weights you use need to be heavy enough, but not too heavy, or that explosive high jump does not need to be extremely high – just high enough. You get the picture!

Whatever the style of training you choose to do, consistency is key. If HIIT is new to you, why not change it up and feel the HIIT?

**When starting any fitness program it is important to ensure you are first fit for exercise. Consult a qualified personal trainer for health and fitness screening prior to commencing any type of exercise, or consult your General Practitioner.

REFERENCES

1. Boutcher, S. H. (2011). High-Intensity Intermittent Exercise and Fat Loss. Journal of Obesity, 2011, 1–10. doi:10.1155/2011/868305
2. Britannica, T. Editors of Encyclopaedia (2022, November 18). Emil Zátopek. Encyclopedia Britannica. https://www.britannica.com/biography/Emil-Zatopek
3. Gibala, M. J., Little, J. P., van Essen, M., Wilkin, G. P., Burgomaster, K. A., Safdar, A., Raha, S., & Tarnopolsky, M. A. (2006). Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. The Journal of physiology, 575(Pt 3), 901–911. https://doi.org/10.1113/jphysiol.2006.112094
4. Maillard, F., Pereira, B., & Boisseau, N. (2017, November 10). Effect of High-Intensity Interval Training on Total, Abdominal and Visceral Fat Mass: A Meta-Analysis. Sports Medicine, 48, 269-288. 10.1007/s40279-017-0807-y
5. Ross, L. M., Porter, R. R., & Durstine, J. L. (2016, June). High-Intensity Training (HIIT) For Patients With Chronic Disease. Journal of Sport and Health Science, 5(2), 139-144. 10.1016/j.jshs.2016.04.005
6. Shiraev, T., & Barclay, G. (2012). Evidence based exercise: Clinical benefits of high intensity interval training. Australian Family Physician, 41(12), 960–962.
7. Talanian, J. L., Galloway, S. D. R., Heigenhauser, G. J. F., Bonen, A., & Spriet, L. L. (2007). Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. Journal of Applied Physiology, 102(4), 1439–1447. doi:10.1152/japplphysiol.01098.2006
8. Tjønna, A. E., Lee, S. J., Rognmo, Ø., Stølen, T. O., Bye, A., Haram, P. M., Loennechen, J. P., Al-Share, Q. Y., Skogvoll, E., Slørdahl, S. A., Kemi, O. J., Najjar, S. M., & Wisløff, U. (2008). Aerobic interval training versus continuous moderate exercise as a treatment for the metabolic syndrome: a pilot study. Circulation, 118(4), 346–354. https://doi.org/10.1161/CIRCULATIONAHA.108.772822

• Bio

Shaun Radford

Having worked and studied in the fitness industry in both New Zealand and Australia for over fourteen years, Shaun has held positions as a group exercise instructor, personal trainer, educator and mentor for personal trainers and training clients. With a passion for education and strong teams, Shaun revels in empowering future personal trainers and businesses to expand their minds and think differently. In recent years Shaun presents at conferences and for businesses on how to take their clients and teams to the next level, aiming for goals to be hit and client retention through inclusive practices and mental health support.