We will discuss about large gap in potential achievements when comparing HIIT to Continuous Training(CT), taking into account a range of common exercise aims. As you’ll see, HIIT is superior to CT in every way.
We’ll now compare the two training methods in the following areas:
- Exercise Enjoyment
- Weight Loss
- Exercise Duration
- Improved Fat Burning Capacity
- Athletic Performance
- Exercise Enjoyment
When most people begin an exercise regime, they assume that CT is the only form of aerobic exercise there is, even though there are many things you can do with CT; treadmills, cycling, rowing, skipping, stair climbing, elliptical trainers etc. Due to the usual fitness advice that new exercisers receive, they envisage many hours toiling away while staring at a blank wall. For most people, CT soon gets boring. Exercising at the same, or very similar levels for 45+ minutes can be rather monotonous for the vast majority of people. Surveys repeatedly show that boredom with exercise is one of the main reasons people give up. I’m sure you can relate to this. What can be more boring than sitting on a stationery exercise bike (or insert machine here) for 45 minutes, peddling away at the same speed and intensity for the entire duration?
A problem with CT is that the thought of only being ten minutes into your run and having another 30+ minutes remaining and at the same pace can be rather demotivating. However with HIIT, knowing that you’re running at an intense pace for only a few more seconds before having a nice easy walk for one or two minutes for example can be pleasing to the mind and can spur you on indefinitely. Working at high intensities is a lot easier if you know you have a rest coming up round the next corner.
who regularly participate in HIIT and for those who are about to find out for the first time– The fact that HIIT is more enjoyable than continuous training should come as no surprise
Weight Loss
Studies have indeed shown that when it comes to weight loss, HIIT is far superior to CT. In 2011 at the University of Western Ontario [3], 20 men and women were assigned randomly to a HIIT group or a CT group. In the HIIT group, subjects were required to run on a treadmill with 4 to 6 bouts of all out sprints lasting 30 seconds. Each 30 second bout of all out sprinting was separated with recovery periods lasting 4 minutes. The CT group jogged on a treadmill at around 65% of their maximal heart rate for between 30 and 60 minutes. Training sessions for both groups took place 3 times per week for a duration of 6 weeks. What were the results? After the 6 week study, subjects in the CT group lost a total of 5.8% of their fat mass. This is great news. But what about the HIIT group? Subjects in the HIIT group lost a total of 12.4% of their fat mass.
The results speak for themselves that HIIT is clearly superior over CT when it comes to fat or weight loss
- Exercise Duration
In the study, the CT group exercised for an average of 45 minutes per session. Compare and contrast that to the HIIT group that exercised only for an average time of 22.5 minutes per session. You read that correctly; the HIIT group exercised for precisely half the time of the CT group. Yet by the end of the study and the subjects all had their body fat percentages taken again, the HIIT group had lost more than double the fat that the CT group had lost; 5.8% in the CT group and 12.4% in the HIIT group.
The study shows without doubt that you can lose more than twice the amount of body fat by performing half the amount of exercise with HIIT over CT.
In practical terms, this means you can shorten your HIIT session considerably and still attain superior benefits over and above a much longer and less interesting CT session.
- Improved Fat Burning Capacity
It is known that the more you exercise the greater fat burning potential your body creates for itself. What I mean by this is that the more you exercise, over time your body becomes more efficient at burning fat no matter if you’re out and about engaging in your daily business or even when you’re sat on the couch watching a movie.
Why is this? There are several mechanisms within the body that makes this the case.
- Increase in mitochondria
The first of those mechanisms is the increase in the number of and the size of the existing mitochondria within the muscle cells. Mitochondria are known as the cells “power houses” as this is where glycogen is oxidised and energy is created. When we exercise, over time the increase in mitochondria and their efficiency enhances the body’s ability to burn fat for us. So how does this increased capacity compare between HIIT and CT? Let’s have a look at another study.
At the University of Guelph, Ontario in 2008 the study was intended to observe HIIT and its ability to improve the body’s fat and carbohydrate metabolic capacities in untrained individuals.
The subjects took part in 10 x 4 minute bouts of high intensity cycling separated by 2 minute recovery periods. Exercise sessions took place 3 days a week for a duration of 6 weeks.
At the end of the study, a resting muscle biopsy was taken and there were found to be increases in citrate synthase (26%), a mitochondrial enzyme and 2 different fat transport proteins (14% & 30%). It was found that while cycling at a steady pace of 60% of their maximal heart rate potential, there was a marked increase in fat and carbohydrate oxidation capabilities
- Excess Post Exercise Oxygen Consumption (EPOC)
The second mechanism I referred to is termed oxygen debt or excess post exercise oxygen consumption (EPOC). If you read a lot on the subject of health and fitness then you may commonly hear EPOC described as the after burn effect.
When you exercise on full burners as you would with a HIIT session, the aerobic system alone cannot possibly supply you with enough energy to fuel the activity. Although it will do its best and give you all it has, the anaerobic system will have no choice but to come into play to provide extra energy assistance. This point typically comes in at between 6585% of your maximal heart rate, as we’ll discuss in the next section.
I will explain the principle of EPOC with the help of an example. Imagine you were going for a swim from one side of a lake to the other. You knew it would take an hour to complete this swim so naturally, you decide to pace yourself. Even if it was your goal to reach the other side of the lake in as fast a time as possible, you would still pace yourself so you wouldn’t run out of energy too soon. But what if a shark suddenly appeared and started to swim towards you? Luckily you see a large rock directly in front, about a minutes swim away; so you turn on the full throttle and give it everything you have to reach the rock in order to save your life.
Now, would you say you would be breathing harder after reaching the rock or after reaching the other side of the lake? Of course the answer is that you’d be breathing harder after reaching the rock. This is because turning on full burners has placed immediate and great stress on your aerobic metabolism; this is partly why you’re breathing so hard.
A very basic evolutionary and physiological principle is that your body adapts to stress. So if you escape from sharks on a regular basis, or better yet, mimic the shark part in a more controlled environment such as a swimming pool then your body is going to change for the better.
Another reason why you are now breathing harder after reaching the rock than when you reach the end of the lake is because you are now requiring additional oxygen to replenish significant energy stores that were used in haste via non-oxidative metabolic pathways (see Energy Systems below) in order to save you from the shark.
- Energy Systems
Each system uses fat and carbohydrate for fuel in different frequencies. Each system is used in different proportions depending on the exercise intensity. They are working all the time in the background and slide in and out of action depending on what we’re doing.
The ATP system is used for high intensity work such as sprinting and lasts usually for 10 seconds or less before becoming depleted. The term ATP refers to adenosine triphosphate which is in rare supply in the body, but don’t worry, once it runs out the body can quickly make it again, luckily for those who do HIIT regularly.
The glycogen/lactic acid system lasts for a bit longer, usually for between 30 seconds to up to 3 minutes and beyond depending on your fitness. Glycogen is the body’s supply of fuel which it uses for everything; it tends to be made available to order.
The aerobic system is the system we use the vast majority of the time; when we’re eating, sleeping, watching TV or performing very light to moderate exercise.
When we perform CT for long periods, we are only in effect using the one energy system; the aerobic system. It’s only when we cross the 6585+% of our maximal heart rate threshold (depending on how fit you are) does the glycogen system come into play. This is where we are in effect utilizing energy on two levels. This is the spot we must aim to hit (or even higher), albeit for only a short duration when partaking in HIIT. In fact in HIIT we should aim to go for 100% of our maximal heart rate in order to train our ATP system also. This way we’re utilizing energy on three levels, not two and not one.
Unlike CT, HIIT gives a workout to all three energy systems and not just the aerobic system. This gives us an all-round better workout and has many physical benefits for us that a less interesting CT session can’t touch.
By participating in HIIT, you receive a large increase in post exercise fat burning over and above what CT can do. You should think of this as free training time because you have ended your workout session, but you body is still burning fat at an elevated rate.
- Athletic Performance
Which sports actually involve long periods of continuous activity? There are a few but really not that many; distance running, distance swimming, distance cycling and distance rowing etc.
When you think about it, nearly all sports involve some kind of stopping and starting action. From combat sports like boxing and martial arts, racket sports such as tennis and squash, all the way to team sports such as football, both American and soccer as well as basketball or ice hockey. Also there are track and field sports such as jumping, both long and high, shot putting or any throwing event and naturally there is sprinting too; all these sports as a consequence of short bursts of high intensity action will involve the rapid build-up of lactic acid.
Therefore dealing with this painful performance crippling lactic acid is of paramount importance to all athletes or even to the recreational sportsman. If you are unable to deal with high lactate concentrations then you will be at a major disadvantage when compared to any opposition who is HIIT trained. And not just your opposition either– But you will also be up against anybody vying for that same position as you on the sports team, for example, your teammates.
As with anything in life, if you want to get good at something then you need to practice it. So if in your sport there is a need to deal with high concentrations of lactic acid, then in order for your body to get good at removing it, you’re first going to need to produce a lot of it. Your body will soon find the best way of dealing with the lactic acid and you will adapt as a consequence. By now you should be well aware that HIIT is the single most effective method of creating this lactic acid build-up.
By now you may not be surprised to know that the improved ability to deal with lactic acid build-ups can come extremely quickly by partaking in HIIT.