This week we’re going to talk about HIIT, or high-intensity interval training. HIIT is on the rise and for very good reasons – firstly, traditional endurance training is known being shown to be bad for our health when performed excessively (more on that in the next blog), and HIIT training has been shown to improve many of the same things as traditional endurance training, with some extra benefits – and all in a fraction of the time. HIIT has been shown to:

• increase aerobic and anaerobic fitness
• reduce blood pressure
• increase mitochondrial biogenesis (the ‘powerhouses’ of your cells)
• improve cardiovascular health
• enhance insulin sensitivity, protecting against diabetes and Alzheimer’s disease
• improve cholesterol profiles
• reduce abdominal fat and body weight while maintaining muscle mass
• burn more calories in less time than traditional workouts

HIIT involves repeated bouts of high-intensity effort followed by varied recovery times. The intense work periods may range anywhere from 10 seconds to 8 minutes long and are usually performed at high intensity (see below for more detail). The recovery period usually lasts for less time than the work periods and are either total rest or low-intensity exercise (see below) and the workout continues with the alternating work and relief periods, usually taking anywhere from 8 to 60 minutes.

Why is HIIT Training so Popular?

HIIT training can easily be modified for people of all fitness levels and special conditions, such as overweight and diabetes. HIIT workouts can be performed on all exercise modes, including various forms such as resistance training (using weights or bodyweight), traditional cardio training (cycling, swimming, running etc.) or a combination of all of them.

HIIT workouts give you a much better ‘bang for your buck’ because they tend to burn more calories than traditional workouts, especially after the workout. This critical post-exercise period is called “EPOC”, which stands for excess post-exercise oxygen consumption, which means that you continue to burn extra calories for a couple of hours as your body restores itself to pre-exercise levels. Now, that’s good news!

HIIT also leads to much quicker metabolic adaptations, which are driven by upregulated gene expression in response to the intense work. What does that mean? Basically, the body realises that it needs to ‘up its game’ and responds accordingly. So if you do long duration steady state runs, your body will respond appropriately. Up the intensity, and the body ups its’ response.

Practical Guidelines for HIIT?

Before you do a HIIT program, consider the duration, intensity, and frequency of the work intervals and the length of the recovery intervals. If you know your max heart rate, ≥ 80% is your desired target, or use a ‘perceived exertion’ of between 7 and 9 on a 10-point scale. Using the talk test as your guide, that range of 7 to 9 goes from ‘it’s difficult to carry on this conversation’ to ‘I can’t talk right now’! The interval should either be rest (for shorter workouts), or 40-50% of your estimated maximal heart rate (around 3 to 5 out of 10) for longer work periods. This would be a physical activity that felt very comfortable, in order to help you recover and prepare for your next work interval.

The relationship of the work and recovery interval is important. Many studies use a specific ratio of exercise to recovery to improve the different energy systems of the body. For example, a ratio of 1:1 might be a 3-minute hard work (or high intensity) bout followed by a 3-minute recovery (or low intensity) bout. These 1:1 interval workouts often range about 3, 4, or 5 minutes followed by an equal time in recovery.

Another popular HIIT training protocol is called the “spring interval training method”. With this type of program, the exerciser does about 30 seconds of ‘sprint or near full-out effort’, which is followed by 3 to 4.5 minutes of recovery. This combination of exercise can be repeated 3 to 5 times. These higher intensity work efforts need to be shorter bouts but can increase up to 60 seconds as you get fitter.

One of our favourite ways to do HIIT workouts at Ritualize is ZUU HIITS – these a variety of bodyweight exercises that we program in a certain sequence (targeting different muscle groups) so that you keep the intensity high without having to stop due to muscle fatigue. Check out Ritualize for these ZUU exercises and try using a work: rest ratio of 20:15 seconds (for beginners), increasing up to 30:10 work: rest for 12 exercises for advanced. That will give you a supercharged 8-minute workout (shown at Ritualize.com under the exercise section) that targets all of your muscles (including ones you didn’t know you had), has a high cardiovascular load (as it’s anaerobic), uses strength throughout range of motion, and increases mobility – no other workout that we know of does this!

How Many Times a Week Can You do a HIIT Workout?

HIIT workouts are more exhaustive then steady state endurance workouts. Therefore, a longer recovery period is often needed. Perhaps start with one HIIT training workout a week, with your other workouts being steady state workouts. As you feel ready for more challenge, add a second HIIT workout a week, making sure you spread the HIIT workouts throughout the week.

A Word of caution!

If you have been living a sedentary lifestyles or haven’t been exercising regularly, make sure you get a check-up before starting HIIT training. A family history of heart disease, cigarette smoking, hypertension, diabetes (or pre-diabetes), abnormal cholesterol levels and obesity will increase the risks.

Prior to beginning HIIT training, it’s a good idea to create a base fitness level by doing some more traditional steady state exercise such as running or only reaching about 60-70% of your maximum intensity during the work periods. Safety in participation should always be a primary priority, and you should focus more on finding your own optimal training intensity, rather than trying to keep up with others.

It’s a good idea to go through the Pre-exercise screening questionnaire on the link below – especially if you are over 40 or haven’t been exercising regularly!