“So what are your thoughts about High Intensity Training?” is a question i get asked quite frequently so i though i would put them down in writing. Partly to help educate people on what my experience and views are and partly because i am lazy and will forever be able to refer people to this as my answer from now on.
So the simplest answer i give people is that it has its place but it is probably one of the most over prescribed types of training and quite often is not the best advice to achieve what people are looking for. For what i am talking about here we will use the example of High Intensity Interval Training, usually running, rowing, cycling etc.
Now Hiit training is great for developing the cardiovascular system and athletic performance. I spent much of my teenage years on an athletics track grinding out such sessions and with them i was able to be a national age champion as a middle distance runner. I still program these type of sessions into some of my clients programs but if i am honest it is very rarely and only when they have a very specific type of goal they are working towards. You see in my experience HiiT sessions are only the best choice when there are one of two goals that are important. The first is athletic performance. If you are trying to develop your anaerobic ability and your bodies skill at being able to both tolerate such conditions and perform athletically under them, then you can’t overlook HiiT. If you play, soccer, are a runner or perhaps even a fighter then this type of training is perfect for you. It will help your body adapt to both the physical and mental stresses of operating in a high workload environment and allow you to perform much better in thisbut the number 1 reason i hear people talk up the benefits of interval training is for its superior fat burning potential and as the number 1 goal most clients are looking to achieve is to burn the fat away it is often prescribed to almost everyone but i can honestly say that in my experience this is definitely not the right advice.
Now before we get into this i would just like to outline the two most common reasons people come to the gym (in my experience anyway). These are to burn fat (lose weight) and build muscle (tone up). Now i quite often hear of studies being done comparing interval training to say walking or jogging. Universally almost all of these studies show that there is a higher calorie burn both during and after (post burn) the interval session but almost always these studies compare workouts of the same duration in time. Say a 20 minute interval session v’s a 20 min walk on the treadmill. Now this is the part that is most often overlooked. If anyone has ever done a 20 minute interval session, taking in the deep breaths, feeling nauseous and tolerating the pain they feel in their lungs and in their legs or done a 1 hour walk on a treadmill and tuned out and watched netflix they will notice a big difference between these two type of training. Firstly, i will concede that the walking would have taken you 3 times longer but even the die hard interval trainers will have to agree, hard intervals kind of suck.
Now i believe a true comparison can be made though between these 2 durations as it is much more realistic to compare 1 hr of low intensity to 20mins of high. Yes i understand there are some people who are time poor but usually when you explain to people that it won’t be overly torturous and you can even watch TV while you do it, they suddenly do have a few more minutes in their day. The other point to note is that if you think you are going to be able to do a 20min interval session and then walk back into work a couple minutes later and not look like a drowned rat who is about to take its last breathe then you haven’t trained intervals properly. Not such an issue after a fast paced walk watching game of thrones for an hour.
Now quite often i hear people talk about the benefits to your muscles from doing interval type training. Yes you are right the increased resistance needed for the high intensity training ie Driving your feet down sprinting or pulling harder on the chain of your concept2 rower could quite possibly increase muscle mass because of the increased resistance on your muscles but why would any one do this? If building muscle is your aim and increased muscle mass is one of the main influences on increased metabolism and calorie burning at rest btw, then why wouldn’t you walk past the cardio section and increase the resistance even more and lift some weights. Its by far the best type of training for that outcome.
So intervals are the best because they burn more calories right… well not necessarily. There is every chance that although you had 3 times longer to do it you burnt more calories during your game of thrones watching marathon but in any case, why is your goal to burn calories? Yes the calories in v’s calories out equation is correct when it comes to losing or gaining weight but did you really want to lose or gain weight? You wanted to lose fat, not weight and you wanted to gain muscle, not weight. So why wouldn’t you be more concerned about the type of those calories burnt and the type of those calories consumed and this is where it gets interesting.
You burn a higher percentage of fat when you are working at a lower intensity. You will almost always burn a mixture of fat and glycogen (carbs) when you are exercising but the ratio of those changes dramatically when the intensity does. The higher the intensity the higher the use of carbs. Skeletal muscle is made up of 1-2% glycogen and the liver can be around 5% glycogen, ready to be released and used by the body. Generally the the body has enough glycogen to sustain around 60-90mins of high intensity exercise. During this type of exercise it is your preferred or go-to energy source. When your body needs energy fast it utilises carbs not fat first. The glycogen is aSo great, you have spent 20mins killing yourself doing intervals to burn carbohydrates calories (you are probably going to replenish with your diet anyway). You might have even increased your cardiovascular ability… but wait a second, you don’t play sport, you are not a competitive rower or a boxer slipping punches in the later rounds of a title fight. You came to the gym to burn some fat and sure, your intervals burnt some fat in that 20 minutes. More than that torturous hour on the treadmill did?… well actually probably not and game of thrones isn’t all that torturous to watch i suppose. But hey you burnt all those calories of carbs off and it only took you 20mins right! Win! Well what if i told you there was an even faster way to get those carb calories off and it takes literally no time at all… drum roll… here it is… just eat less of them in your diet in the first place. So if you don’t need to improve cardio performance and you want to decrease your glycogen stores you can do it with diet and don’t have to kill yourself doing intervals? Yep… pretty much that is what i am saying.
Please don’t think i am hating on intervals, i’m not. They are great. They are just not the answer to every situation. Much like walking isn’t always the answer either or that anything i have said here should be applied as a protocol for anyone without consideration of all the aspects of their situation. the best piece of advice i can give you is that you are unique. What you want to achieve and the constraints in which you have to achieve them are unique to you. The type of training you do and your dietary needs should be matched directly with these goals. Please seek out the help of someone who knows what they are doing and can devise a plan that matches your desired outcome. I’m not even saying that person might be me, there are many very competent trainers out there (many more that aren’t) but please don’t become one of those misguided people with all the drive and work ethic in the world who are ultimately going to toil away, killing themselves and achieving zero results before giving up, never to set foot in a gym again and all just because they didn’t have the right plan in place from the get go..