HIIT Workouts: Programming, Exercises, and Benefits

Pete McCall
Pete McCall
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One of the most common misperceptions that many fitness enthusiasts have about exercise is that it is necessary to spend hours working hard and sweating buckets to get results.

Nothing could be further from the truth. Workouts featuring High Intensity Interval Training (HIIT) can deliver many benefits without taking a lot of time. Benefits include burning fat, increasing muscle definition, reducing the risk of developing a chronic health condition, or simply burning off some stress.

There are many reasons why HIIT you should consider adding HIIT to the workout programs you design for your clients. 

One of the benefits of working with a NASM-Certified Personal Trainer is that they can design the workouts that can help clients get results in the shortest amount of time possible, and HIIT is one tool that makes that possible.

How to structure a hiit workout: 3 models to use

There are many ways that HIIT can be organized; structuring the work and recovery intervals to create the desired overload while allowing for the appropriate recovery is one of the MOST important components of a HIIT workout.

HIIT can take a variety of different forms; during the workout, the goal is to work as hard as possible during the work interval and use the recovery periods to allow clients to catch their breath and prepare for the challenge of the next interval of high-intensity exercise.

Tabata training is a popular model of HIIT. It calls for 20 seconds of work followed by 10 seconds of recovery, repeated eight times in a row for a total of 4 minutes; that might not seem like a lot, but when each 20-second bout is performed at the highest level of effort, 4 minutes is that is needed for a great workout! One option with new clients is to start with 2 minutes of a Tabata protocol, then allow a 1-minute recovery before finishing with the final 2 minutes; this will challenge clients to work hard but allow for a little more recovery so they can be successful and complete the entire 4 minutes.

Another model, 30:30, calls for 30 seconds of high-intensity exercise followed by 30 seconds of lower intensity for active recovery repeated for 6-10 minutes. When working with clients, start with 5 minutes, which would be 5 - 30 second intervals, and work up from there, for example, on a rowing machine: 30 seconds of all-out effort, followed by 30 seconds of low-intensity, repeated for a total of 5 minutes.

A third model is 30-20-10; in this format, work intervals are organized into 60-second increments. The first 30 seconds is low-intensity, then 20 seconds of moderate-intensity followed by 10 seconds of an all-out, high-intensity work effort.

An example using bodyweight would be a high plank for 30 seconds, 20 seconds of push-ups at a steady pace, and finishing with 10 seconds of explosive push-ups. You could challenge a client to do the same exercise for 3-to-6 minutes in a row, or you could develop a circuit of exercises following the 30-20-10 protocol. When creating circuits for 30-20-10 workouts, for the best results, allow for 10-15 seconds to transition between exercises.

Key things to remember about high intensity interval training

An effective HIIT workout should start like any other workout with a comprehensive warm-up consisting of self-myofascial release (SMR) on tight muscles, two-to-four core training, and balance exercises to ensure optimal neuromuscular efficiency.

Also, it helps to include one or two plyometric exercises to activate the type II, explosive, muscle fibers. Throughout the warm-up, the intensity gradually increases to an intensity where talking comfortably becomes challenging. Once a client is breathing hard and sweating, he or she is ready to HIIT it!

The Most Effective HIIT Equipment in the Gym

In a fitness facility, the most effective HIIT equipment options are the rowing machine and HIIT bike (with the moving arms) because they are ergometers, meaning that there is no adjustment for intensity, like speed on a treadmill, the faster the client works, the greater the resistance.

A second benefit of using a rower or HIIT bike is that they require the arms and legs to work together, which increases overall calorie expenditure. To provide additional motivation when using a protocol like Tabata, record the number of calories burned or distance traveled during the workout (take a picture of the display with the client's phone); the next time the client does the same protocol, they will try to meet or beat those numbers.

Read also: Tabata Workout Benefits

Two Common Mistakes of HIIT Programming

Many fitness professionals understand the basics of HIIT but often make two critical mistakes that could limit the benefits while increasing the risk of injury: the first common mistake is making the workout hard for the sake of being hard.

Often times workouts are designed to be too hard to try and capitalize on the afterburn effect (or EPOC).

The second mistake is doing too much high intensity without allowing for adequate recovery. This blog will provide a brief overview of HIIT's science and how you can use it to design workouts to produce the results your clients want.

Understanding HIIT

HIIT is a form of cardiorespiratory exercise that alternates between periods of short duration, high-intensity work, and bouts of lower intensity movement to allow for active recovery that uses a 1-10 scale of perceived exertion with ten being the highest.

High intensity can be considered anything over an effort level of eight, while the lower intensity active recovery intervals should be an effort level of 6 or below. Another way to look at it, you should perform the high intensity intervals to the point of being breathless and unable to talk.

In contrast, the recovery intervals are long enough to get breathing back under control. HIIT training calls for exercises to be performed for short time frames, ranging between 10-and-45 seconds. You should be working at the highest intensity possible, followed by brief active recovery intervals that are only long enough to allow an individual to begin catching their breath and talk without too much difficulty.

The good news is that you can perform HIIT on almost any type of exercise equipment, including traditional cardio machines, non-traditional strength training tools like kettlebells, heavy ropes, and medicine balls, or no equipment at all.

6 Benefits from HIIT Workouts

Here are six essential benefits from HIIT. With them you can supply a rationale for the effectiveness of HIIT workouts to your clients. 

Additionally, these benefits will highlight why you should use it in the programs that you design for your clients and group workout participants.

#1 HIIT can help reduce the risks of developing many chronic health conditions.

Consider HIIT as strength training for the cardiac muscle of the heart. The high-intensity intervals help the heart become more efficient at moving blood around the body, reducing the risk of developing heart disease.

High-intensity work intervals rely on anaerobic glycolysis to produce adenosine triphosphate (ATP), the chemical used for energy, from glycogen without oxygen. Anaerobic glycolysis helps muscle cells become more efficient at metabolizing carbohydrates and helps reduce the risk of developing onset diabetes.

Finally, because HIIT can burn so many calories, it allows clients to maintain healthy body weight and significantly reduce the risk of becoming obese (Gibala, et al., 2012).

#2 HIIT can increase muscle size and definition

The type II muscle fibers used for anaerobic glycolysis are also the ones responsible for increasing muscle hypertrophy. When type II muscle fibers are consistently required to use glycogen for high-intensity exercise, they will adapt by storing more glycogen for future workouts.

Because molecules of glycogen hold on to water molecules, as muscle cells store more glycogen, they can increase in overall size (Buchheit & Laursen, 2013). (Note: as glycogen is metabolized into ATP, it releases the water and carbon dioxide, which explains why our breathing becomes quicker, to move carbon dioxide out of the body, and we sweat during a high-intensity workout).

#3 With HIIT, muscles will continue burning calories after the workout

During a HIIT workout, the muscle will metabolize carbohydrates for fuel. However, after HIIT, type I muscle fibers will metabolize fat for energy in the post-exercise recovery period as the body returns to its normal resting state (Buchheit & Laursen, 2013).

With HIIT, clients burn a lot of calories during the workout. Still, they will continue to burn calories afterward. Their muscles replace the depleted glycogen and begin the repair process for any muscle proteins damaged during exercise.

#4 HIIT could result in increased mitochondrial density in type I muscle fibers, and more 

HIIT can result in increasing the density of muscle fibers, improved stroke volume in the heart's left ventricle, and enhanced aerobic capacity.

All of which were previously thought to occur only as a result of long, slow distance (LSD) training protocols (Gibala et al., 2012). Ask clients which they would rather do, exercise consistently for forty-five minutes, or work as hard as possible for less than ten?

Yes, HIIT can be challenging, but the good news is that discomfort is over quickly, allowing more time for the client to do other things in his or her day.

#5 HIIT can help elevate the anabolic hormones responsible for growing new muscle proteins.

As part of the repair process after a HIIT, the body will produce human growth hormone (HGH), testosterone (T), and insulin-like growth factor-1 (IGF-1) to repair damaged muscle proteins (Buchheit & Laursen, 2013). Consistent HIIT combined with regular strength training could help increase these hormones' overall levels, resulting in an overall increase of lean muscle mass.

#6 HIIT could help reduce the risk of developing Alzheimer's or dementia.

Brain-derived Neurotrophic Factor (BDNF) is a protein that helps promote the growth of new brain cells.

HIIT has been shown to have a more significant impact on elevating levels of BDNF when compared to moderate-intensity, steady-state exercise (Szuhany, Bugatti & Otto, 2015). Challenging HIIT workouts won't only strengthen a client's muscles but could help them strengthen their brain as well.

Things to consider before structuring a HIIT Workout:

The human body expends about five calories of energy per liter of oxygen consumed. HIIT workouts that involve upper and lower-body muscles working at the same time use more muscles, which, in turn, consume more oxygen and burn more calories. When it comes to HIIT, it's the intensity and not the workout duration that can have the greatest effect.

Therefore focus on designing workouts between four and ten minutes in length (not counting the warm-up) (Gibala et al., 2012). Challenge your clients to work as hard as possible during each work interval by ensuring the workout will be short, and once it's over, they won't be doing any more excessively strenuous exercise.


HIIT is beneficial, but it can place a tremendous amount of stress on the body. Therefore, it should only be performed two to three times a week with at least 48 hours between exercise sessions to allow a full replenishment of energy stores and repair the involved muscle tissue. It is still possible to exercise the day after a HIIT session.

Still, it should be lower- to moderate-intensity activity and use different muscle groups or movement patterns than those used in the high-intensity workout. Now that you understand a little more about HIIT and the benefits it provides, you can add it to your clients' programs knowing that it is one of the most effective tools for getting better results in a shorter amount of time.


Buchheit, M. and Lauren, P. (2013). High-intensity interval training, solutions to the programming puzzle; Part II: Anaerobic energy, neuromuscular load and practical applications. Sports Medicine. 43. 927-954.

Gibala, M., Little, J., McDonald, M. And Hawley, J. (2012) Physiological adaptations to low-volume, high-intensity interval training in health and disease. The Journal of Physiology. 59(5). 1077-1084.

Szuhany, K., Bugatti, M. And Otto, M. (2015) A meta-analytic review of the effects of exercise on brain-derived neurotrophic factor. Journal of Psychiatric Research. 60. 56-64.

The Author

Pete McCall

Pete McCall

Pete McCall is a NASM-CPT, PES, Certified Strength and Conditioning Specialist (CSCS), international presenter, host of the All About Fitness podcast, fitness blogger and an author of several articles, textbook chapters and the book Smarter Workouts: the Science of Exercise Made Simple. In addition, Pete holds a master’s degree in exercise science and has been educating fitness professionals for more than 15 years. Currently Pete lives in Encinitas, CA where he is an education consultant and content creator for Core Health & Fitness, Terra Core Fitness and 24 Hour Fitness.


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