High Intensity Interval Training

  The picture illustrates the training outcomes of two athletes at the extreme ends of their sports; a marathon runner (slow steady state cardio) and a 100m sprinter (high intensity interval training). Although there is a clear difference in age, body types and genetics, the difference is revealing.

This blog will state why high intense interval training is a far quicker and more effective way of burning fat compared to steady state cardio transforming you to a whole new fitness level in half the time.

High Intensity Interval Training (HIIT). 

High Intensity Interval Training involves integrating very intense spells of exercise with low intensity exercise. 

What is Slow Steady State?

Steady state cardio involves running, cycling or any form of cardio related exercise for an extended period of time at a more or less consistent pace.

Steady State Cardio Vs High Intensity Interval Training (HIIT)

Steady state cardio is popular amongst the masses in an attempt to ‘lose weight’. What does the research say? Early 1493171_650747721656678_511510802_nexercise physiologists advocated that “steady state” cardio was supreme for fat loss because relatively more fat is used by the body as fuel at lower exercise intensities (60 – 70% Mhr). Many fat loss experts such as Craig Ballantyne have debunked this as a myth. While studies agree that one burns more fat relative to glycogen (the fuel our muscles use) when going for a jog, but what we want to achieve is total fat burn. At higher intensities, you are burning far more fat, even though the fat/glycogen burning ratio is lower. In addition, interval training allows you to exercise at very high intensities for a much longer period of time than steady state, so you burn more fat.

Weight Loss: Where does it all go wrong?

As a certain body type may adapt to running long distances everyday, they inevitably lose weight which looks great on the scales but often this weight loss includes both fat and muscle. An extreme example of this is the photo of the marathon runner. What happens when we lose muscle?

  • Decreased strength
  • Poor Performance
  • Early Aging
  • Reduced Immunity

Due to loss of muscle, our metabolism slows down meaning we inevitably gain our lost fat and more when we go back to eating normally. Often, people resort back to a form of long steady state form or aerobics or do another crash diet and restart a vicious circle.

Fat loss: the Solution.

So what is the best solution for healthy weight (ie: fat) loss? There are many viable answers depending on the clients body type and goals that can be modified through integrating HIIT. Most studies agree the best solution is to incorporate metabolic weight training with a well designed program, the second is HIIT circuit or interval training, the last thing is going for a jog. Lets look at the benefits of metabolic training and HIIT as it relates to this bootcamp circuit training:

Metabolic Training.

In brief, metabolic training is the completion of structural and compound exercises with little rest between exercises in an attempt to maximise calorie burn and metabolic rate during and after the work out. Structural and compound exercises require a considerable output of energy to perform multiple muscle exercises like ‘burpees’ and ‘squat jumps’ and weight-lifting. The rationale behind this strategy of fitness is to improve muscle composition and cardiovascular capacity simultaneously. The end result is a more energetic, leaner body in half the time. Metabolic training is high intensity anaerobic exercise that leaves you breathless – if you are not breathing hard after a metabolic workout, something is wrong.

Benefits of Metabolic Training:

  • Improved fitness
  • Greater strength
  • Peak Performance
  • Delayed ageing (and in many cases, rewinding the body clock)
  • Reduced risk of illness


There is also a powerful afterburn effect called ‘EPOC’ (excess-post exercise oxygen consumption) associated with anaerobic circuit training that increases your metabolism and calorie intake up to 24 hours post workout – this can become significant training 4 times a week. Long aerobic jogs resorts to virtually no calorie burn post work out.

In more detail:

  •   Increased Aerobic/Cardiovascular Capacity. Studies have shown that anaerobic exercise improves one’s oxygen uptake (V02 max) which increases overall aerobic capacity faster than low intensity cardio.
  • Improved hormonal profile for lipolysis (fat loss). Exercise physiologists have agreed that HIIT training aids the production of fat burning hormones and weight training associated with HIIT generates the most powerful hormonal response for fat loss.
  • Significant calorie burn. Although the exact calorie burn for metabolic workouts remains unclear due to certain variables, what is known is that it burns a considerable amount of calories. The estimated calorie burn for a 30 minute intense metabolic workout is comfortably around 500 calories. Whats more, the metabolic rate increases from 10 – 25% up to 2 days after the workout (some studies went up to 72 hours). This equate to hundreds of extra calories which over a course of a number of workouts can become profound.
  •  Increased Lactate Threshold. This helps your body become more efficient at flushing out acidosis (lactic acid) out of the system enabling you to go faster for longer which is essential for sport.
  • Improved Insulin Sensitivity. As mentioned earlier, gaining lean muscle helps increase insulin sensitivity restoring blood sugar levels faster. The consumption of stacked carbs with proteins facilitated with insulin release can actually help push the proteins into muscles which is an important part of already lean people looking to develop size and strength.
  • The Anabolic Effect. The anabolic (building up) effect advocates that HIIT combined with the right diet promoting slightly more calories can increase muscle. The opposite occurs with long duration steady state cardio which causes you to lose muscle (catabolic). There is a stigma among women who think that they will instantly turn into a lump of muscle only looking at a weight, it is worth mentioning that women have 10 – 30% less muscle hypertrophy bearing hormones than men. Incorporate this form of body weight training into your program and watch your body tone up in a matter of weeks.

In conclusion I must be clear in stating that going off for a jog is not bad for you – anything that gets people moving is a good thing. Integrating a form of cardio into a program is a must for me. There is a place for slow steady state cardio with certain individuals from a range of different physiological status. However, comparing it to interval training as an effective form of cardio to burn fat and it seems like child’s play. I would adopt a balanced approach to training for my clients to keep things fresh and interesting. It is important to become informed about the science to change popular beliefs and attitudes to better suit your goals and take your fitness to the next level.

BOOK NOW and reserve your earlybird spot for the 6 week Spring Bootcamp Program 2015 at Tower Bridge and Haggerston Park.


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  4. Babraj, John A., et al. “Extremely short duration high intensity interval training substantially improves insulin action in young healthy males.” BMC Endocrine Disorders 9.1 (2009): 3.
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  7. Mikkola, J., et al. “Concurrent endurance and explosive type strength training improves neuromuscular and anaerobic characteristics in young distance runners.” International journal of sports medicine 28.7 (2007): 602-611.




Chris Cahill