Anyone who’s done any significant amount of cardio for weight loss knows that it comes with diminishing returns. The more you do cardio, the less effective it is for weight loss / fat burn. You read that right. The MORE cardio you do, the LESS it tends to work!
The reason stems from something a lot of people refer to as “metabolic adaptation”. Or, put another way, the tendency for your body to adapt to whatever conditions and circumstances you throw it at. Your body doesn’t want to lose weight. In fact, it will fiercely resist any and all efforts to burn fat, because it views those stores as an essential energy reserve. The first few weeks or months of cardio will really throw your body for a loop, and force it to dip into those fat reserves for the energy it needs. But after that? Your body’s preference is simply to slow your metabolism to adjust to the cardio, to prevent needing to burn fat. Ouch…
The typical proof-point for this are marathon trainers… The long duration, steady-state cardio actually causes many people to GAIN WEIGHT! It’s not necessarily a bad thing, but it can sure be frustrating for people trying to use cardio as a tool for burning fat.
I experienced this personally, as well. Once I reached the 205lb mark, I could not get the scale to move no matter what I tried. I eventually took up running and other cardio and found that it was super effective. However, after losing 15-20lbs doing heavy cardio every night, it stopped working. I was still putting in the workouts, I was still eating properly, but the weight stopped coming off!!
The solution is HIIT… Which stands for High Intensity Interval Training. And I wish to be very clear that I will often times ask people what kind of workouts they do, and they will respond “High intensity intervals”. (usually it’s a word that’s printed on the cover of the DVD they use, or a term that’s been throw at them by their group-fitness instructor). However, after a little probing, it’s pretty clear that what they’re doing isn’t HIIT at all!!
First, some vocabulary words
(don’t skip over this… you need this to understand HIIT.. I promise..)
Aerobic Workout: Simply put, this is a workout that puts your body into an aerobic state. That is, when you are working out and you start breathing heavy. In this state, your heart-rate goes above about 120bpm, and your body requires more oxygen. This is really where fat-burn starts. The aerobic state is relatively easy to identify because, although you might be working hard and breathing heavy, you know that you could state in that zone for a relatively long period of time if needed (15 minutes, a half hour… or even more.. ).. You are working hard, but you aren’t going to pass out at any moment.
Anaerobic Workout: If you keep working hard during an aerobic workout and you push to go as hard and as fast as you possibly can. you will (almost immediately) move to a stage where you feel like you can’t get enough air and you start to feel as though you might pass out. (This is what happens if you start running at an all out sprint as hard and as fast as you can for as long as you can. ). You can’t stay in this zone for more than about 90 seconds at a time. (Note: This is why most people believe that they “hate running”… because when they first start out, ALL running is anaerobic, and it’s miserable!!) Note that your heart-rate in this zone is usually above 180, and you may even feel like you’re going to throw up.
LISS = Low Intensity Steady-State.…. This is the kind of cardio that long-distance runners typically do. They’ll start running, they’ll get into a zone, and they’ll stay in that zone for the duration of the race. It has to stay “low intensity” in order for them to have the fuel needed to run the long distances required. A person’s typical heart-rate in this zone is going to be between 120 and 155. In this zone, you are working hard, you are sweating, but you could probably carry on a (somewhat awkward) conversation with someone next to you if required.
MISS = Moderate Intensity Steady State … This is what most people do in a group-fitness setting (spin class, kick-boxing, etc.), and even your typical short-distance runner will typically stay in these ranges (over a 5k run, for example). The typical heart-rate in this zone is in the 145 to 175 range. In this range, you are breathing too hard to talk to the person next to you, and you are definitely sweating profusely. If your cardio workouts aren’t in the MISS zone, you’re missing out! This is where fat-burn gets serious.
…. Almost all people who do cardio with any sort of regularity will fall into one of these two categories. And to be very clear, there’s absolutely nothing wrong with either! LISS and MISS have countless health benefits, and yes, they will help you burn fat to a certain point. But, as stated above, LISS and MISS workouts will become less effective for fat burn the more often you do them.
This is where HIIT comes in.. “High Intensity Interval Training”
HIIT, put simply, is when you are doing a cardio workout and you constantly move your body between the MISS zone and the Anaerobic zone. You push as hard and as fast as you can for 60 to 90 seconds, then you back off for a few minutes. Then you push yourself back into the anaerobic zone for as long as you can stand it, then you pull back. Wash, rinse repeat. It’s not nearly as much fun as typical cardio, because when you are full anaerobic, you basically feel like you’re going to pass out. It hurts. You can’t get enough air. And your body is BEGGING you to stop. For this reason, very few people do HIIT properly — because it’s immensely uncomfortable.
You can do HIIT with ANY kind of cardio.. Here’s what a typical workout would look like:
First, get warmed up and start your workout. Get yourself into the MISS zone where your hear-rate is in the 145 to 175 range. (If you don’t own a heart-rate monitor. Buy one. They are essential!)
- Stay in the MISS zone for about 3 minutes. You are working hard. Your heart-rate is in the 145-175 range. You are sweating. You could not carry on a conversation with someone even if you wanted to.
- Move to the Anaerobic zone. Your heart-rate should exceed 180. You are miserable. The harder you push, the harder your body begs you to stop. Stay in this zone until you simply can’t do it anymore. (60 to 90 seconds).
- Move to the LISS zone for 60 seconds. Your heart-rate should quickly fall back into the 140’s to 150’s. If you were running, you would slow to a walk. You won’t stay here long.. Just enough time to catch your breath.
- Repeat from Step #1.
Here’s what your heart-rate should look like during a typical HIIT workout:
Do this for the duration of your workout, and you will burn… are you ready… ? Up to FOUR TIMES the calories you would burn doing normal LISS or MISS cardio!!!!! Scientists don’t completely understand WHY this happens, but they do know that the calorie burn continues up to 36 hours after the workout ends when you do HIIT properly. It has SERIOUS fat-burn potential!
And the best part about HIIT? Your metabolism and your body simply cannot adapt to it. It will ALWAYS have positive returns. You will ALWAYS burn fat doing it!!