What is HIIT?

[heidilw]

I have seen this posted throughout the forum... what is it, and why should one do it?

 

[wishes]

High Intensity Interval Training

 

[Fenster]

If you google it you will find lots of info, but here is one article for you to check out if you like.

 

[M2M]

Steve wrote this in his diary:
http://weight-loss.fitness.com/weight-loss-diary/8425-journey-not-destination-4.html

Steady state cardio (running at the same intensity for prolonged periods of time) uses primarily fat stores as its energy source. Back in the day, this fact led many to believe that SS cardio was the preferred method of exercise for shedding the pounds.

How does HIIT differ from this? Actually, first let's discuss what HIIT is for those who may not know. HIIT is simply the alteration between high intensity and low intensity training intervals. This can be done with any form of exercise, such as running, cycling, swimming, elliptical training, etc. For instance, you may set up a 1:2 protocol. You will set a total training duration, in this case assume 20 minutes. You can split these 20 minutes up however you would like. For simplicity's sake, let's assume we do 10, 2-minute intervals totaling the 20 minutes. Each of these 10 intervals is then broken up into the high/low intensity intervals. Going back to the 1:2 ratio we set up, we would exercise at high intensity for 40 seconds and immediately follow this with a low intensity bout lasting 80 seconds totalling a single 2-minute interval. Follow this principle for each of the 10 intervals. That, in a nutshell is HIIT.

So, back to how HIIT differs from SS cardio. HIIT uses primarily carbohydrates as its fuel source. This may not seem logical to you; it may seem better to burn fat then carbohydrates if fat loss is the goal. Stick with me though!

Total daily energy expenditure (TDEE) plays a much larger role in fat loss, and HIIT drastically increases your TDEE. So now we are talking energy (calorie) balances instead of fat burning. After a bout of HIIT, something known as excess post-exercise oxygen consumption (EPOC) is increased.

While you may burn more calories and fat during SS cardio, when you factor EPOC into the equation, you actually end up burning more energy performing HIIT rather then SS cardio.

The beauty of HIIT lies in the fact that you do not have to, nor should you be able to, train as long as you would with SS cardio. In a nutshell, HIIT is more effective due to the increase EPOC and energy utilization and more efficient due to the time consumption issue.

There are many other benefits of HIIT. It tends to keep your Type IIa muscle fibers on the fast twitch side of the spectrum. Type II muscle fibers are those used for quick utilization, explosion, and power for activities such as sprints or weight training. Type IIb are for pure power. Type IIa are your middle of the road fibers. They can take on qualities of both fast twitch or slow twitch. SS cardio tends to keep these Type IIa fibers on the slow (type I) fiber side and HIIT tends to keep these on the fast (type II) fiber side.

Although HIIT is considered to be an anaerobic exercise, it has been proven to also improve aerobic capacity.

It has been shown that HIIT elevates the level of growth hormone (GH) in the bloodstream, which is never a bad thing for those of you looking to add lean muscle. (This should be all of you!)

Some studies show that your resting metabolic rate remains elevated for over a 24-hour period after a bout of HIIT.

There is more to be said, but I hope at this point, for those of you who did not understand why HIIT is so popular right now, you now see the importance of utilizing this type of training. For those of you looking to shed some fat or for those of you looking to maintain muscle while improving your cardiovascular systems, this is for you.

 

[TomO]

About 3 weeks ago, I bought some of the soundtracks on cardiocoach.com (I have no relationship to them, other than as a satisfied customer). Some people find them a bit cheesy, but I really like them. The routines last from just over 30 minutes to a couple that are over an hour long and involve 20 hill climbs/sprints. I do them on the elliptical, and for the first time, I actually enjoy my cardio workouts.

Most of what I've read says not to do HIIT every day. If you're just starting out, do them maybe twice a week, and if you get in better shape, you can do them 2 to 3 times a week. Just make sure to give your body a day's rest in between, because it's a grueling workout!

I do my HIIT routines with a Polar heart rate monitor that displays the rate right on the machine, making it easier to see when you're in the right zone.

When I started a month ago, my resting pulse was 61. This morning, it was 51, a pretty substantial improvement.

When I reach my target weight (about 20 months from now) I plan to do HIIT regularly just to maintain. The nice thing about it is that you can do a shorter workout and burn just as many calories as you would during a workout almost twice as long.

 

[MysticCat89]

In my thread, someone told me to check this out because I want to lose weight as fast and possible and am not afrad of reverting to unsafe weigh loss methods if I don't fix my problem fast enough. Anyway, how in the world is this HIIT thing supposed to do any good? I understand what it is, but doesn't cardio simply make you burn calories, which only makes you hungry? So, it's exercise at high intesity, get hungry, eat or fight hunger, then go to no results, or basically starve? Please understand that I am not criticising anyone; I'm just curious to understand this. At one point I was playing DDR on some of the harder setting (standard and chalenge) then went to slower stuff to cool down back to faster/harder stuff for 4-6 hours every day for a month and noticed nothing but an increased appetite. Aside from the time I put in, how is HIIT any different from what I was doing?

 

[wishes]

you probably want to ask Steve this in his journal (see link earlier M2M posted)

 

[TomO]

In my thread, someone told me to check this out because I want to lose weight as fast and possible and am not afrad of reverting to unsafe weigh loss methods if I don't fix my problem fast enough. Anyway, how in the world is this HIIT thing supposed to do any good? I understand what it is, but doesn't cardio simply make you burn calories, which only makes you hungry? So, it's exercise at high intesity, get hungry, eat or fight hunger, then go to no results, or basically starve? Please understand that I am not criticising anyone; I'm just curious to understand this. At one point I was playing DDR on some of the harder setting (standard and chalenge) then went to slower stuff to cool down back to faster/harder stuff for 4-6 hours every day for a month and noticed nothing but an increased appetite. Aside from the time I put in, how is HIIT any different from what I was doing?

HIIT has three main benefits:
1) It trains your cardiovascular system to work under a much heavier stress load. For me, this has translated into significantly lower blood pressure readings (today's reading was 113/67, for example). HIIT also helps your endurance as far as lactic acid goes.

2) HIIT boosts your metabolism for up to 18 hours after the session. This is through a process called EPOC (you can Google it for more info), which basically is the replenishment of oxygen throughout your entire body. So even though your session by itself may only expend 300 calories, the boost in your metabolism can double that. By the way, EPOC is one of the things that makes weight lifting a good way to lose weight, too.

3) HIIT is a good alternative to steady state and interval cardio. That keeps you from getting bored, and your body from getting too accustomed to the same sort of exercise. That said, HIIT doesn't need to become the only weapon in your cardio arsenal. I do all three forms of cardio, and it's helped me immensely.

 

[Steve]

In my thread, someone told me to check this out because I want to lose weight as fast and possible and am not afrad of reverting to unsafe weigh loss methods if I don't fix my problem fast enough.

This makes a whole lot of sense. Knowing all that we know today, specifically, that losing weight in an unsafe manner always results in weight regain in an amount equal or greater to the initial weight loss..... why on Earth would you revert to using it?

I am assuming that unsafe = starvation type dieting

Anyway, how in the world is this HIIT thing supposed to do any good?

Have you really read the HIIT stickie and/or my post from above? If you have, do you think you actually comprehended it? It would seem not from where I am standing.

Actually, I don't think you understand how the body works, hopefully no offense taken. Let me try and clarify below.

I understand what it is, but doesn't cardio simply make you burn calories, which only makes you hungry? So, it's exercise at high intesity, get hungry, eat or fight hunger, then go to no results, or basically starve?

Your logic is flawed.

Look, our bodies are in constant flux of building up and breaking down. That is metabolism at its core. We speak of maintenance often in here. Maintenance caloric intake. The maintenance level is the amount of energy it takes to fuel the building up so that it balances out the breaking down. Maintenance assumes that you have exactly enough energy to support all the vital functions of the body plus activity. Weight stays the same.

When you're eating under maintenance, you're providing less energy than is required to maintain that balance. The body needs that energy, so it gets it from the only choice it has: the existing tissues. In a perfect world, this is fat. In the real world, it's fat and muscle (another reason high protein is important while dieting. Aminos in the blood stream = less need to break the muscle down to get them. Muscle is how the body stores protein).

But guess what? You can create this deficiency of energy anyway you'd like. You can eat less. You can expend more without changing the amount you eat, simply by increasing your activity. You can use a combination of the both. A deficit of energy is a deficit of energy not matter which way you slice it.

I reread your above quoted statement and I am still having trouble understanding what you think. You said, " So, it's exercise at high intensity, get hungry, eat or fight hunger, then go to no results, or basically starve?"

Are you suggesting that adding exercise into the mix ultimately leads to no results and starvation? It would appear from above that this is your logic. I am not sure why or how though. Maybe you can elaborate your line of reasoning, please?

Or did my explanation above shed some new light for you?

Please understand that I am not criticising anyone; I'm just curious to understand this.

Of course not. I don't think anyone will take it as so. Nobody expects anyone to understand everything, nor is anyone going to get mad when someone asks questions. Questions are good.

At one point I was playing DDR on some of the harder setting (standard and chalenge) then went to slower stuff to cool down back to faster/harder stuff for 4-6 hours every day for a month and noticed nothing but an increased appetite. Aside from the time I put in, how is HIIT any different from what I was doing?

Number one, 4-6 hours of exercise per day is extreme over-kill and most likely counter-productive.

Number two, when you increase activity (exercise), to an extent, you must fuel that activity. Kind of hard to exercise when you are starving. Your body will send all of the signaling to send you into extreme hunger.

Losing weight on a consistent basis and keeping it off permanently is a very delicate process of handling your energy fluxes with due care. Move to extremes and your body is going to resist the effort to an extent that is not manageable.

DDR, from what I know of it, is a form of interval training. There are periods of higher intensity exercise and there are periods of lower intensity. Seems like a great form of exercise to me. However, as I said before, there is a period of diminishing returns. You don't have to do it for such an extreme amount of time.

 

[Wrangell]

HIIT has three main benefits:
1) It trains your cardiovascular system to work under a much heavier stress load. For me, this has translated into significantly lower blood pressure readings (today's reading was 113/67, for example). HIIT also helps your endurance as far as lactic acid goes.

2) HIIT boosts your metabolism for up to 18 hours after the session. This is through a process called EPOC (you can Google it for more info), which basically is the replenishment of oxygen throughout your entire body. So even though your session by itself may only expend 300 calories, the boost in your metabolism can double that. By the way, EPOC is one of the things that makes weight lifting a good way to lose weight, too.

3) HIIT is a good alternative to steady state and interval cardio. That keeps you from getting bored, and your body from getting too accustomed to the same sort of exercise. That said, HIIT doesn't need to become the only weapon in your cardio arsenal. I do all three forms of cardio, and it's helped me immensely.

Good post TomO.

Succinct and to the point.

 

[simplysassy]

just starting HIIT

I have just started to integrate HIIT into my regular workouts.

I am doing this on the elliptical trainer. I start at level 10 now and change up to level 20 (which is the highest on the machines I use).
However, as I am in the early stages, I am doing this every 3 or 4 minutes, with a high level of about 35-50 seconds.
I then go back to my lower level for about 3 or 4 minutes.
I plan to change up more often- perhaps every 2 minutes for a 30-50 second high level intensity.

I find when I change up to the highest level I cannot move as fast as I can at a lower level. I am giving it my all, though.

Is this enough for now? Do most people start out slower and gradually move up as to how many times they do the increase within the cardio workout itself?
Is any of this comprehensible to those reading this? Please reply to my email at: reneesb2000@yahoo.ca

thanks