Tuesday, March 12, 2013

HIIT - Cardio at its finest

Hey guys,

I haven't written about cardio training yet. This was mainly caused by a lack of time I recently had so that I haven't done any cardio training for the past few weeks. Now I have some more spare time (but still not that much) and I want to fill it 2 times a week with short "High-Intensity Interval Training (HIIT)"-sessions.

When you ask someone about effective cardio training for fat loss, probably the answer will be that you should run/row/swim with low-intensity for a longer time (at least 30 minutes). One main argument for this advice is that your metabolic system changes its main energy source from glycogen (carbs) to fat after approx. 20 minutes of low-intensity training and then your body starts to burn fat as fuel. Another point is that it's comfortable and you can relax your mind with slow long runs. So far so good....

BUT even though it's true that steady state cardio does bring you in your fat burning mode, your body won't burn much of it...in fact, long sessions let your body become very efficent with its sources which leads to a very small amount of energy that is needed. That way you burn fat, but just a little (very little!).
If you are like me, then you prefer results. You prefer a fast loss of fat, and efficiency is the last thing you need for that. What's the solution? Use HIIT as your main cardio training!

HIIT means that you alternate high-intensity intervalls with low-intensity recovery parts. You won't get in the efficient fat-burning zone with HIIT, but you gonna burn so much more energy (cal) that your body is forced to burn a huge amount of fat afterwards because your glycogen storages are already empty after the cardio session (and, as you know, the human body still needs energy for living, adaption after workouts and so on). There's one more effect that helps you burning even more energy and fat AFTER your training session as well - the after burn a.k.a. EPOC (excessive post-exercise oxygen consumption). During a HIIT your body will be in an anaerobic zone for most of the HI-time where oxygen is in short supple and your body produces lactic acid due to a second way of energy supply (without the use of oxygen). This energy from anaerobic exercises lasts for just a few seconds (up to 20-40 sec) which also is the reason why nobody can sprint for an hour but almost anybody can do it for 10 seconds. After your HIIT training your body contains a lot lactic acid which it has to remove with effort. And this is the reason why you burn additional energy after the session.
So you have a higher energy consumption during the session and also a few hours afterwards...sounds great, doesn't it?

As a side-note it is mentionable that, if you follow a low-carb diet (like mine), your body doesn't have that much glycogen in its storages so that it is forced to burn fat as fuel (instead of glycogen which is produced by carbs) almost instantly by starting your cardio training. You can burn even more fat with the combination of HIIT and a low-carb diet!

A possible HIIT-design (also the one I use), which was developed by a Swedish scientist, is the following:

5 minutes warm-up (important to prevent yourself from injuries due to the high intensity of the session)

1 set equals 5 reps of:
30 seconds fast walking/very slow running
20 seconds running at your normal pace (faster than the first 30 seconds)
10 seconds sprinting as fast as you can

Do 3-4 sets like this with a 2 minute walk between every set.

This HIIT-design also works with swimming, biking, rowing...

If you want to, you can use other high-intensity intervals as well like running up a hill for some seconds and walking it down again slowly, but I prefer to stick to the 30-20-10 stuff first.

Btw: Also endurance-orientated athlets could profit from HIIT because their heart and lungs become more efficent and stronger!

That's how I do my cardio work...what about you?