Training

The Truth About HIIT Training By Luke Worthington

Do we know what HIIT training actually is? Let’s unpack the truth about HIIT training and bust some commonly believed myths.

Why did it shoot to stardom in the noughties?

HIIT workouts are inspired by a piece of research performed by Japanese sports scientist Dr Izumi Tabatta in 1996. (’Tabatta’ training is often used as an interchangeable term for HIIT training.) Dr Tabatta’s research demonstrated a greater calorific burn from shorter interval training, than from longer aerobic activity. This was attributed to a phenomenon known as EPOC (Excess Post Exercise Oxygen Consumption) or known colloquially as ‘afterburn’.

However, this is unfortunately based on a misunderstanding of the work that Dr Tabatta did:

In the actual study one group performed moderate intensity (70% VO2 max) aerobic activity for one hour, 5 days per week. The other group performed a 10 minute moderate intensity (70%) warm up followed by 7-8 sets of 20 seconds at 170% of VO2 max with 10 seconds rest – they performed this for four of the five days, and on the fifth they performed 30 minutes (70%) moderate intensity exercise.

So, worth noting that the HIIT training group performed 70 mins of aerobic activity ON TOP, of the interval work.

The key point to understand is, that VO2 max is measured by gradually increasing the resistance on a cycle ergometer whilst measuring their oxygen uptake. The point at which the persons oxygen uptake no longer increases is measured as their VO2 max – in other words complete exhaustion and often accompanied by nausea. So, in this study that point was reached – and then resistance/ work rate increased another 70%!

You can imagine how mentally and physically demanding it would be to reach a point of exhaustion and then push that far beyond it. It’s a performance level that Olympic cyclists, rowers, and triathletes may reach – but very few others are capable of.

A bodyweight routine of burpees, star jumps and treadmill sprints (however tough it may feel) is nowhere near the level of intensity that was created in Dr Tabatta’s lab that created the famed ‘afterburn’ effect.

Should a 170% of VO2 max effort be achieved by an athlete through any other means – then by definition, it physiologically cannot be sustained for a 45 minute exercise class.

True bouts of HIIT – as per the original study – can be achieved by very few, under very specific circumstances, and even then, repeated for only a few minutes. In those rare cases where it can be achieved, HIIT training requires a significant amount of time to recover from.

Unfortunately, there are no shortcuts when it comes to health and fitness and whilst short sharp interval-based workouts absolutely have a place, they should make up just one small part of a balanced exercise regime.

What should a well-structured program include?

A well-structured program should include elements addressing all five measurable ‘pillars’ of fitness:

1) Muscular Strength

2) Work Capacity (or cardio fitness) consisting of: aerobic training (long duration low intensity) and anaerobic training (shorter duration, higher intensity). HIIT training fits as one part of this subsection

3) Mobility and Motor Control

4) Body Composition

5) Emotional Wellbeing

The quantity, frequency and emphasis placed on each of these 5 pillars will depend upon the individuals starting point and their specific wants, goals and needs. Bearing in mind that a person’s wants can be different to their needs, a good trainer should have the skills to strike this balance! A sensible beginners program may consist of two full body resistance training sessions per week, two low intensity cardio sessions, and one shorter interval based session.

But what about fat loss?

Whilst this has recently become a bit of a taboo subject in the health and fitness world – training to improve body composition is still a valid reason to exercise and in fact is the most common reason people have for initiating a health and fitness program.

Planned exercise, however, makes up only around 10% of our daily calorific expenditure –so regardless of exercise choice we would still need to address energy balance and protein intake in order to create changes to body composition – whether that is fat loss or muscle gain.

When it comes to improving any of the measurable health markers a combination of resistance training, low intensity cardio and a small amount of high intensity cardio is by a considerable margin, the most effective, efficient and sustainable method.

Truth about HIIT training