If you have been looking for an efficient way to burn fat and improve cardiovascular health, you have likely asked: What is high-intensity interval training? Often referred to simply as HIIT, this exercise method involves short bursts of vigorous activity performed at maximum potential, followed by brief periods of rest or low-intensity recovery. While the rigour of a HIIT routine can be intimidating, its popularity among fitness trainers and athletes continues to grow.

But is this the right workout for you? Research suggests that the benefits of High-Intensity Interval Training may actually exceed those of traditional, steady-state cardio. However, because of its demanding nature, understanding both the HIIT benefits and risks is crucial before you dive in. Whether you want to incorporate it into your existing routine or start a new HIIT workout programme, knowing the science behind the sweat is the first step toward reaching your fitness goals. Research suggests that high-intensity interval training (HIIT) has benefits that may exceed those of exercises that involve a steady pace.  Let’s discuss!

Understanding What is high-intensity interval training? Can help you make informed decisions about your fitness journey.

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What is High-Intensity Interval Training?

High-intensity interval Training (HIIT) is described as the performance of exercise moves at a high intensity (burst of optimal speed) for usually thirty (30) to Sixty (60) seconds to a few minutes with periods of recovery between (Shiraev and Barclay, 2012).  While it is often still considered aerobic exercise, it is an amplified version of the standard steady-paced exercise.

High-Intensity Interval Training (HIIT) purportedly is associated with many benefits, including improving cardiovascular and metabolic outcomes and improving blood pressure and inflammatory markers.  As such, it is considered a useful routine for individuals who are healthy and those who may have health problems.

High-intensity interval Training (HIIT) is not considered a new concept. However, more and more fitness trainers and enthusiasts have been incorporating it into their fitness routines. Additionally, this kind of intervention was applied many years ago, in the 1970s, in what was known as the ‘Wingate Protocol’, a common HIIT intervention used then (Bar-Or O et al. 1977).

In this intervention, thirty (30) seconds of cycling was performed at maximum effort with four (4) minutes of recovery. This was repeated Four (4) to Six (6) times per session, Three (3) times per week (Gibala and McGee, 2008; Boutcher, 2011).  This resulted in only a weekly workout duration of 2 to 3 minutes, and with great results (cardiovascular and otherwise).  Therefore, HIIT may be able to help those who lack sufficient time to exercise to both start and maintain a regular exercise programme or schedule.

In this article, we will explore three (3) major health benefits of High-Intensity Interval Training (HIIT) and any risk factors associated with its performance. These include cardiovascular health, better breakdown of fat and carbohydrates for fuel and increased energy when exercising and post-exercise

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Three (3) Major Health Benefits of ‘HIIT’

If you are looking for maximum results in minimum time, High-Intensity Interval Training (HIIT) is the ultimate game-changer. By alternating between short bursts of intense effort and brief recovery periods, HIIT pushes your body further than traditional steady-state cardio ever could. It isn’t just about burning calories in the moment; this specialized training style triggers a powerful physiological response that improves your heart health and metabolism long after you’ve left the gym. Here are three “awesome” reasons why you should consider adding these intervals to your routine.

1. High-Intensity Interval Training and Cardiovascular Health

Studies have shown that High-Intensity Interval Training (HIIT) may not only provide similar benefits as standard or continuous endurance training but may offer even superior results (Helgerud et al. 2007; Wisloff et al. 2009).

In a study by Helgerud and colleagues, it was found that just running for Four (4) minutes at a time, repeating Four (4) times with Three (3) minutes of active rest (i.e. light jogging in place, etc.) and performing this activity for Three (3) days per week for Eight (8) weeks resulted in a greater improvement in stroke volume when compared to slow distance training which usually employs more time (Joyner and Coyle, 2008).

According to the National Institutes of Health (NIH), stroke volume refers to the volume of blood that the heart’s left ventricle pumps when it contracts (systolic contraction). Any improvement in stroke volume will help to maintain normal mean arterial pressure (Bruss and Raja, 2022; nih.gov).

Additionally, a study by Slordahl and Colleagues in 2004 shows that HIIT training was able to increase left ventricular heart mass by twelve (12%) percent as well as cardiac contractility by thirteen (13%) percent.  However, it must be noted that these results were comparable to standard aerobic exercise.  The duration of the HIIT sessions was not mentioned in this study.

The positive results on the body in performing HIIT are because these types of exercises are usually able to achieve what is described as ‘maximal oxygen consumption’ (VO2max), sometimes to the tune of Ninety (90%) percent and over (Slordahl et al. 2004).   Maximal oxygen consumption (VO2max) is the ability of the body to consume, distribute and utilize oxygen to produce energy (Slordahl et al. 2004).  As such, it is typically used as a predictor of exercise performance.  As such, any improvement in the function of the cardiovascular system will improve or increase an individual’s VO2 max. 

To this extent, those who suffer from cardiovascular diseases should aim to improve the function of the cardiovascular system as well as their VO2 max (Daussin et al. 2008).

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2. High-Intensity Interval Training and the Breakdown of Fat and Carbohydrates

HIIT was observed by researchers to be better able to break down both carbohydrates and fats and use them as fuel for exercising.  This is due to a result of the increase in Mitochondria (Zuhl and Kravitz, 2006; Gibala, 2009).  Mitochondria are considered the energy source of our cells.  As such, it uses oxygen to create what is known as Adenosine Triphosphate (ATP) (Zuhl and Kravitz, 2006; Gibala, 2009).  ATP is the main or only fuel for the contraction of muscles.

Therefore, when an individual performs exercises like HIIT, the muscle’s storage of ATP will be used up or depleted.  As such, the muscles must maintain normal contractile function through the continuous synthesizing of ATP (National Institutes of Health).

As such, with increased mitochondrial density, the body will have more energy for those working muscles (Zuhl and Kravitz, 2006) and thus the muscles will be able to work longer, helping you to experience better results and endurance. For example, running at high intensity for a longer period, of course, with proper breathing and recovery.

In a study by Burgomaster and Colleagues in 2008, it was found that performing HIIT with Four (4) to Six (6), Thirty (30)-seconds of maximal cycling sprints (your optimal intensity), followed by Four (4) and a half (½) minute of recovery for Three (3) times per week led to a more effective breakdown of fat and carbohydrates for fuel.  This was due largely to an increase in mitochondrial oxidative enzymes (remember, those used to make ATP).

The results of Burgomaster and colleagues’ study were likened to those who performed between Forty (40) and sixty (60) minutes of continuous endurance of steady cycling, five (5) days per week and at a VO2 max of Sixty-five (65%) percent.

You can read the detailed article on running and its health benefits here.  In this article, you will also learn how to include running in your fitness routine for weight loss.

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3. High-Intensity Interval Training and an Increase in Energy Post-Workout

An increase in energy after working out was observed as another benefit of performing HIIT.  This, according to research, is referred to as Excess Post-Exercise Oxygen Consumption (E.P.O.C).  This is because after performing HIIT, both oxygen consumption and caloric expenditure remain high or elevated as the cells of the muscles that were worked restore themselves to pre-workout levels (Zuhl and Kravitz, 2006). 

This results in both higher and longer post-workout caloric expenditure (Zuhl and Kravitz, 2006; LaForgia et al., 2006).  Hence, you will often hear people say that they continue to burn fat after performing HIIT. This is the reason for that phenomenon.

How Many Times per week must I Perform High-Intensity Interval Training?

Research suggests that at least three (3) times per week can produce optimal results (Daussin et al. 2008).  Additionally, the duration of HIIT routines may vary depending on one’s fitness goals. However, fifteen (15) to thirty (30) minutes are often seen as ideal for great, long-term benefits and results.

Remember to take time to recover between sessions.  This is particularly important as it helps the body and heart rate to recover as well as prevent injuries.

What are the Risks in Performing High-Intensity Interval Training?

Risks exist with all physical activities, and exercising, in this case, HIIT. Since HIIT increases heart rate intensity more than other aerobic activities, it is recommended that warm-up, recovery time and cool-down be of paramount importance. 

Additionally, less is more. Do not believe that increasing quantity (time and routine) will allow you to experience improved benefits. This is not the case with HIIT, as the body can become fatigued and experience more injury.

Illustrative Summary

Here is an illustrative summary of the three (3) Major Benefits of Performing High-Intensity Interval Training (HIIT).

Let’s Sum Up!

An important goal of any exercise programme is to improve one’s physique and overall health.  This was largely the argument for regular cardiovascular or aerobic exercise.  However, research has shown that High-Intensity Interval Training (HIIT) can lead to even better results in a shorter period.

As such, incorporating high-intensity interval training (HIIT) into your regular exercise plan should be a worthwhile consideration, especially if you want to lose weight and improve your physique and overall health.

So, now that we have explored three (3) of the major benefits of performing HIIT, is this a programme you would incorporate into your workout sessions, if not yet? If you already perform HIIT regularly, what’s your routine like?  Share it nuh!

You can read more about exercising and its benefits, as well as other exercises that can help you to lose weight, tone and strengthen the abs, and start your fitness programme.  Click the articles below:

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This article was last updated by a Research Consultant and Certified Nutrition Coach: January 14, 2026