High-intensity interval training for weight/fat loss and structure
There are many definitions of high-intensity interval training online but one of the best one is a HIIT is a form of exercise that involves brief, intermittent bouts of high-intensity exercise, interspersed by periods of rest or low-intensity exercise. We may say that HIIT involves short duration exercise sessions. Similar as a circuit training.
What is the key in HIIT exercise programme structure? It’s the careful manipulation of exercise intensity.
Let’s now define the term high-intensity. When we say a high-intensity exercise, we usually think about the exercise that gets us the maximum oxygen uptake or as we know it VO2 max. VO2 Max is the maximum amount of oxygen that your body can use.
There are many methods to calculate VO2 Max but this is one of the most convenient:
VO2 max = 15.3 x (MHR/RHR)
MHR- Your maximum heart rate (208- 0.7x your age)
RHR- Your resting heart rate in 1 minute
We can classify HIIT into two categories:
- Sprint interval training or SIT
- Aerobic interval training or AIT
For our weight loss goal, we will be focusing on aerobic interval training. The main difference between sprint interval training or aerobic interval training is that aerobic interval training uses longer work periods. This system places a greater demand on our aerobic energy system.
Aerobic interval training and structure
There are two types of aerobic interval training:
- Long aerobic interval training
- Short aerobic interval training
I will describe briefly each type and then we will move on to the structure.
Long aerobic interval training uses extended work periods of about 3-4 minutes of high-intensity exercise (equivalent to 80-95 % VO2 Max) with 3-4 minutes rest periods. There are usually 4-6 work periods in the training session.
On the other hand, short aerobic interval training uses shorter work periods of about 15-60 seconds of high-intensity exercises (equivalent to 90-170 % VO2 Max). Rest periods between work periods needs to equal or slightly less than the work period.
If you are a complete beginner it’s prudent to start with regular CET and then proceed with long aerobic interval training. Before designing your personalised high-intensity weight loss programme, your fitness expert needs to assess you and take into the consideration your base level of cardiorespiratory fitness.
Let’s take a look at the sample structure of AIT.
|Exercise||Work periods||Intensity||Rest periods|
|Cycling-Spin Bike||4 minutes||80-95 % VO2 Max||3 minutes|
|6 work periods|
The next best progression in this system for those beyond beginner’s status is to instead of rest periods have an active recovery periods. For example, in the above case, you would keep cycling but at a very low intensity (up to 50 % HRmax) to bring your heart rate down.
The next structure that I will present is a SAIT or short aerobic interval training. Let’s take a look.
|Exercise||Work periods||Intensity||Rest periods|
|Rowing machine||20 seconds||90-170 % VO2 Max||20 seconds|
|8 work periods/intervals|
In the example above, we have 8 work periods with 20 seconds work and 20 seconds rest. Again, you can progress gradually by incorporating a low-intensity row instead of a traditional rest period.
How would I approach my HIIT training if I am beginner and I have my weight/fat loss goal in mind?
First of all I would make sure that I have experience with CET training approach, then I would jump to LAIT and then to SAIT training approach. How long you spend on each training phase will depend on your progression and fitness level. Each training phase needs to be personalised further.
So far you heard me saying personalised for a millionth of time, and it is for a reason. I cannot give you a specific advice in this format as each one of us is unique and with different response to training stimulus. I can only offer you a guidance and some structure then your fitness expert will lead you further towards your weight loss goal.
How does EPOC fit in the high-intensity nature of HIIT?
Scientists discovered that the high-intensity nature of HIIT results in an elevated energy expenditure during the exercise and there is an increase in energy expenditure for a number of hours following high-intensity interval training. This phenomenon is due to an excess post-exercise oxygen consumption or EPOC. We talked about EPOC in one of our previous blog posts.
Also, HIIT training approach has been shown to increase fat oxidation during and after exercise, which can have a positive impact on the whole metabolism and body fat loss over time. Furthermore, exercise intensity has been suggested to influence circulating levels of hormones that influence appetite.
HIIT is a great training approach if you have a weight/fat loss goal in mind. However, start first with a regular CET to improve your cardiorespiratory base. Then you can start adding LAIT into your weekly training plan and lastly SAIT. The progression needs to be gradual and never all-out.
Proper personalised nutritional plan needs to follow HIIT for weight/fat loss.
Until next writing,
Damir Pervan, TrainChampion, Founder and CEO