The list of benefits of HIIT seems to be getting longer each week. From reducing fat mass to decreasing heart disease, HIIT can help. In the book High-Intensity Interval Training, the author tells us that the health and fitness benefits of HIIT are so potent that it is 'now increasingly being prescribed by doctors to patients with all manner of conditions and ailments.'
In this article, we’re going to take a look at four benefits of HIIT. The benefits are a mix of fitness and health. So, as well as looking at how HIIT can promote aerobic and anaerobic capacity, we’ll also see how it can improve body composition and decrease disease risk.
But you’ll be pleased to know, this blog is not all theory. Concluding each benefit, you’ll find a link to a HIIT workout to try. In addition, links to other resources, such as training guides, session plans, and books are littered throughout.
Benefits of HIIT
Before we venture into the main part of the article, below is a list containing a broad range of health and fitness benefits associated with HIIT. The list showcases the many ways high-intensity interval training can improve health and promote physiological development.
Those benefits highlighted are the ones that are covered in more detail further down.
Reduced fat mass
Increased muscle definition
Improved cardiovascular efficiency
Enhanced muscle endurance
Engages multiple physiological systems simultaneously – such as the cardiovascular, respiratory, and muscular systems
An impressive list by anyone’s standards. And though impressive, it’s not quite complete. According to Driver, author of High-Intensity Interval Training, to the above list could be added improved athletic performance and increased oxygen uptake (VO2 Max) and anaerobic threshold.
That concludes the brief tour of HIIT-related health and fitness benefits. If you’ve had your fill and are eager to get going, have a bash at this HIIT Bodyweight Workout.
But if you’re eager to know more about the benefits of HIIT, read on . . .
Benefits of HIIT #1: Improved body composition
Body composition is ‘expressed as a percentage of total body mass or as absolute fat mass,’ (ScienceDirect – 2022). Typically, people that use body composition assessment methods – such as the BMI – do so to ascertain how much fat they are carrying as a percentage of total body weight.
HIIT is both an effective and efficient method of reducing fat and improving body composition. Training at high intensities encourages the body to metabolise fat as fuel.
But this is nothing new. The relationship between high-intensity training and weight loss has long been established. For decades coaches and athletes have been using HIIT to burn fat and boost performance (High-Intensity Interval Training).
However, according to one leading authority on the subject, there is an ‘ever growing consensus’ that HIIT is a more effective way to reduce body fat than conventional forms of exercise. For example, this 30-minute HIIT workout could burn as many calories as a ‘steady state’ session of twice the duration.
This insight is brought to our attention in a Harvard Health article. A professor of medicine is cited as suggesting that replacing long low-intensity workouts with short-duration HIIT could help burn considerably more body fat in much less time.
Why reduce body fat?
Carrying excess body fat is bad for our health. Established (and emerging) research has identified a host of diseases and conditions linked to being overweight. Today ‘the harmful effects of obesity are not in question,’ says Professor Lieberman, author of the internationally acclaimed Exercised | The Science of Physical Activity and Rest.
Aside from the burden of lugging around superfluous weight, which can overload joints and interfere with breathing, excess fat cells can ‘ignite chronic low-grade inflammation.’ Chronic or ‘persistent’ inflammation ‘damages tissues throughout the body’ and may increase risk factor for Alzheimer’s.
Obesity and disease
An important 2022 literature review that raises awareness of the possible early-onset cancer epidemic, cites hundreds of research studies that link high body mass index (BMI) with a litany of diseases.
For example, a high BMI is associated with an increased risk factor for stroke, type 2 diabetes, coronary heart disease, and several types of cancer – including cancer of the head, neck, throat, gastrointestinal system, and all major organs.
The above literature review outlines a number of simple yet effective ways of reducing body fat. In addition to reducing the consumption of processed food, animal protein – especially red meat and processed meat – saturated fat and alcohol intake, we are advised to eat more fruit, vegetables, and whole grains.
Another very important lifestyle factor for reducing disease risk and all-cause mortality is exercise. Engaging in regular physical activity has been shown to be a potent method of maintaining healthy body weight.
Related: This Skipping HIIT Workout incinerates fat
Benefits of HIIT #2: Reduced risk of heart disease
A common misunderstanding about heart disease is that it’s just something you get. It's a condition that can strike anyone, anywhere, and without warning. And when that unfortunate person has heart disease, there’s absolutely nothing that can be done to slow, stop, or reverse the condition. From that point on it’s a slow decline to death.
The great cardiologist, researcher, and author Dr Dean Ornish has well and truly dispelled the above myths. His program for reversing and curing heart disease is based on cardiovascular research conducted over two decades. The outcomes of that research are clear: ‘people can begin to reverse their heart disease by changing their lifestyle.’
Those lifestyle changes include reducing saturated fat intake, eating more fresh fruit and vegetables, and replacing processed, refined carbohydrates with whole grains. (Get started on your dietary transition with these super-healthy plant-based recipes.) Another lifestyle factor high on Ornish’s list for reducing heart disease is exercise.
Exercise helps reduce heart disease
‘Regular exercise,’ he tells us, helps ‘you reduce your percentage of body fat.’ The many health benefits of exercising and reducing body fat were outlined in HIIT Benefit #1: Improved Body Composition. However, Ornish adds a few more benefits to that list.
In addition to increasing the density of blood vessels and the number of mitochondria, regular exercise increases bone density and reduces blood pressure while also decreasing the formation of blood clots (Dr Dean Ornish’s Program For Reversing Heart Disease – p330).
Prevention is better than the cure
But why wait until you’ve got heart disease before you do anything about it? As the saying goes, prevention is infinitely better than the cure.
Those very same lifestyle factors identified above, if implemented as permanent features of your current lifestyle, can significantly reduce the risk of heart disease in future life.
Incidences of heart disease are near to non-existent in people who observe plant-based dietary principles and exercise frequently. Practicing the nutritional advice espoused by Dr Gregor in his best-selling book How Not to Die, will ensure that you reduce your saturated fat intake while significantly increasing your consumption of fruit, vegetables and whole grains.
In addition, participating in regular exercise, such as this HIIT Running Workout, will help you burn excess calories and maintain a healthy body weight. These two lifestyle factors alone could dramatically decrease heart disease risk.
Benefits of HIIT #3: Increased cardiovascular fitness
HIIT is widely used to improve anaerobic capacity. Anaerobic training, remember, refers to the type of exercise that breaks down blood glucose to fuel activity.
The anaerobic threshold is reached when lactic acid creation exceeds the body’s ability to remove it (High-Intensity Interval Training). Because anaerobic training does not depend exclusively on oxygen (fat and water), it can only be sustained for short durations – minutes at most.
However, while HIIT is the training method of choice for increasing the anaerobic threshold, it can also be used to develop the aerobic system (Physiology of Sport and Exercise – 5th Edition).
HIIT can enhance aerobic and anaerobic energy systems
Because the interval length can range from as little as 5-seconds to as much as 10-minutes, HIIT possesses the capacity to stimulate both the aerobic and anaerobic energy systems in the same workout. The effectiveness of HIIT for promoting one system or the other can be further modified by varying the intensity of the intervals.
For example, if you wanted to focus your HIIT workout on developing cardiovascular fitness, you would extend the interval length but decrease the intensity. The reverse method would be applied to extend the boundary of your anaerobic threshold.
In terms of physical performance, increasing the capacity of these systems can enable you to a) sustain a consistent output for longer, and b) achieve a higher upper-maximum pace.
Related: HIIT Home Workout
Benefits of HIIT #4: Improve whole body conditioning
HIIT is often misunderstood as a training method comprised only of super-intense, short-duration bursts of activity – usually sprinting. This is an unfair representation of what is a diverse and bewilderingly adaptable form of exercising.
The intensity, speed, resistance, and exercises of a HIIT workout can be modified and adapted to suit a broad range of fitness goals. If you aspire to improve muscular endurance, you could create a HIIT Circuit that incorporates cardio and resistance exercises.
In addition, HIIT can be tailored to suit a specific sport. This HIIT Boxing Workout not only improves your fitness and muscle endurance but also your pugilism. Such workouts help to develop whole body conditioning. For example, the aforementioned workout will:
Improve aerobic (cardio) fitness
Push the boundaries of the anaerobic threshold
Improve body composition
Engage every muscle in the body
Enhance muscle endurance
Sharpen muscular definition
Provide a high engaging whole-body workout
HIIT can improve whole body fitness conditioning
In contrast to your typical gym session (reps, rest, repeat), HIIT tends to involve elements of cardio and muscular endurance. Thus, in a single workout, you can train multiple components of fitness.
As well as being an altogether more efficient method of training, HIIT enables you to develop a broader range of physical attributes. Instead of spending a whole session on strength training, workouts such as this HIIT Kettlebell Circuit afford you the opportunity to improve aerobic fitness, functional strength, and muscular endurance.
In short, those who incorporate HIIT into their training regime will forge whole body fitness conditioning. Get started today with this HIIT Cardio Workout.
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Driver, J. (2017) HIIT: High Intensity Interval Training. CreateSpace. UK.
Greger, M. Stone, G (2017) How Not to Die. Macmillan. USA.
Harvard Health article ‘harnessing the power of high intensity interval training’ – accessed on: https://www.health.harvard.edu/heart-health/harnessing-the-power-of-high-intensity-interval-training (Accessed: 28 – 9 – 2022)
Nature Reviews Clinical Oncology early-onset cancer epidemic. A literature review.
Ornish, D. (1990) Dr Dean Ornish’s Program For Reversing Heart Disease. Ballantine Books. USA.
ScienceDirect: Body composition is ‘expressed as a percentage of total body mass or as absolute fat mass.’ https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/body-composition (Accessed: 6 – 10 – 2022)
Wilmore, H. J, Costill, L. D (1999) Physiology of Sport and Exercise Second Edition. Human Kinetics. United States.