Does anyone else do HIIT?

I do, and the main reason to do cardio is, as the name implies, for your cardiovascular health.

I've read mixed things on it as a fat lot burner. Also I'd like to know if 30 minutes of interval sprints burns more calories than 30 minutes of moderate cardio.
There's a lot of outlandish claims made as to "fat burning". Always keep correlation and causation in mind.....

The highest calorie burn would be the highest intensity you could maintain for the full 30 minutes.
As a guess your intervals and "moderate" cardio could be about the same (but could be less, or more...).
Beware that interval training is far harder to get an accurate calorie burn estimate than steady state, the intervals and recovery periods throw off HRM estimates badly.

Are there any other benefits of doing HIIT, and should I still do some cardio anyway?
Depends on your goals, current capabilities, what other exercise you do.
A lot of structured programs include both steady state and intervals. Different pros and cons.
But as you don't like steady state then the exercise you like wins hands down.

Beware studies that show HIIT being far superior to steady state as they tend to end the study at the point where the initial rapid improvements from HIIT tails off and steady state continues to progress.

I'm probably in the minority in believing (genuine) HIIT and weight training is a bad mix, both create stress and need recovery time.

For my goals as a cyclist I do a majority of steady state (which doesn't mean it's low intensity) but supplement with interval training, but typically long duration intervals with various patterns from 2:30 to 12 minute intervals.

robs_ready wrote: »

I've read mixed things on it as a fat lot burner. Also I'd like to know if 30 minutes of interval sprints burns more calories than 30 minutes of moderate cardio.

For context, I'm a runner. My anaerobic training comes in the latter portion of a training cycle just before the taper as it's a method of increasing maximum output.

With that in mind I'm not really using these sessions as a means of burning calories. The mileage I do means I struggle to keep up anyway. That said, having worked it out, including EPOC, a sprint session lasting c 30 minutes is about the same as a steady state, threshold pace, run for 30 minutes.

That's because in a sprint session I'll warm up for ten minutes, do 6-8 cycles of 100m sprint with a 60 second recovery, then cool down for another 10. In that time about 75-80% of the running is at easy pace anyway.

As upthread, lots of outlandish claims about HIIT, but when you analyse it you'll see much of that content is nonsense.

I do some HIIT here and there to mix it up, but personally the cardio benefit is limited IMHO. I think I've improved my cardio base quite a bit more with longer intervals at high intensities, along with lower effort training for longer periods. But I've put more time into the alternate training as well.

Fat burning? Still comes down to deficit IMO, but the HIIT will deplete glycogen quicker.

I'd love to convert the elliptical to rotational, or buy a good power measure for the bike, for HIIT type stuff. Once I started exceeding the meter for instant output on the elliptical doing Tabata level stuff got sort of hit and miss. At those output levels, keeping track of data gets harder quick.

I personally haven't found recovery from Tabata type stuff that terrible. But I think many are not able to gauge power and are going all out vs outputting to a certain power level. That alone could really change the picture quickly in regards to how many intervals they could do, HR rise, and obviously recovery.

kcjchang wrote: »

Funny how everyone is doing HIIT (and liking it) have no way to guage the intensity of what they are doing.

Don't include me in that everyone. I've just exceeded the instantaneous readout on my metered machine, leaving me at "keep going but guess" levels until I can calculate it after the fact.

AnvilHead wrote: »

sijomial wrote: »

...I'm probably in the minority in believing (genuine) HIIT and weight training is a bad mix, both create stress and need recovery time...

Lyle addresses that issue and recommends no more than 1-2 HIIT sessions per week due to the increased demands upon the CNS and the recovery issues it can create/exacerbate.

As you touched upon above with your parenthetical comment, most people who think they're doing HIIT aren't really doing HIIT. For those who actually are, it's highly strenuous and very taxing. HIIT, as the name implies, is intervals done at absolute maximal effort bracketed by recovery periods. The fatigue and exertion is cumulative and places very high demands upon the muscular, circulatory and nervous systems. While it has benefits, there's certainly such a thing as "too much of a good thing".

This exactly. I don't do HIIT regularly now, but I "thought" i was doing it in the past. I WAS doing interval running on a treadmill, and it wasn't close to HIIT (you can't really do HIIT on a treadmill, it's unsafe and transitions too slow).

HIIT is supposed to be balls to the walls, 100% maximum effort. The first time I finished doing real HIIT on an eliptical I was walking like a drunk and almost fell over, and wanted to puke and die. If you don't feel like that at the end of it, you're probably doing it wrong!

IE1 protocol? Only Olympic speedskaters, as test subjects, who can manage over 8 cycles of 20 seconds "on" and 10 seconds "off" intervals of 170% of VO2 Max at 85 rpm four times a week plus a day of steady-state training remained in the study, "not taxing", you're joking right? (By the way, anything less than four times a week is not IE1 protocol aka Tabata HIIT.)

If IE1 is too easy, try IE2 protocol. Not sure what's the point since Tabata's study found that physiological index magnitudes deteriorated in the last 10 sec of each repetition of IE2 and IE1 protocol taxed both the anaerobic and aerobic energy releasing systems almost maximally, but go for broke.

kcjchang wrote: »

IE1 protocol? Only Olympic speedskaters, as test subjects, who can manage over 8 cycles of 20 seconds "on" and 10 seconds "off" intervals of 170% of VO2 Max at 85 rpm four times a week plus a day of steady-state training remained in the study, "not taxing", you're joking right? (By the way, anything less than four times a week is not IE1 protocol aka Tabata HIIT.)

If IE1 is too easy, try IE2 protocol. Not sure what's the point since Tabata's study found that physiological index magnitudes deteriorated in the last 10 sec of each repetition of IE2 and IE1 protocol taxed both the anaerobic and aerobic energy releasing systems almost maximally, but go for broke.

I think the most I've done it in a single week was 3 times, but have no doubt that the week long protocol is within the grasp of a normal and reasonably trained average Joe or Jane. I did it with other workouts in that day that exceeded the single day of steady state, and I'm no genetic freak of nature by any means.

The point on the IE2 protocol is no doubt quite valid, and I think for most that extra 10 seconds would be very taxing for the heart rate. But that also brings up the point I was making that without a power measure it would be very easy for someone to overdo it with the IE1 as well. My all out 100% short term effort would easily exceed 170% of VO2max, but I doubt me or any other average person would do it for many intervals.

Intervals should be a supplement to improving your over all cardiovascular health... think of intervals as muscle building for your heart, lungs diaphragm and circulatory system... NOT as a stand alone "fat burner" exercise. As some posters have suggested the idea is to approach "failure" levels in respiratory and muscle endurance during the "go" portion of the exercise... and to "recover" as quickly as possible...coming from a middle distance track back ground...We were coached to do intervals as a way to increase overall speed in middle and long distance running... don't let anyone tell you you can't do intervals on a treadmill... you just need to be able to step off the belt quickly for the rest interval... My current "poison" is the stairmaster... 30 seconds to 1 minute at my max pace... followed by 1 minute to 1:30 rest before stoking the fire again... interval training should be done using your biggest muscle groups (legs) in order to hit the anaerobic wall as quickly as possible... so stairs, track, or hills are the best "instrument of destruction"... when you hit your max... you should be uncomfortably out of breath and like going another 10 seconds is impossible... or you should be building to that level... To begin intervals you should absolutely have your doctor's input and already have a strong cardio "work ethic"... Intevals should never be done "cold" always warm up before beginning...

what Intervals will really do is turn a jogger into a runner... if you ever had designs on a sub 5 minute mile... this is what intervals were designed to do... make you faster and stronger for longer...

snerggly wrote: »

This exactly. I don't do HIIT regularly now, but I "thought" i was doing it in the past. I WAS doing interval running on a treadmill, and it wasn't close to HIIT (you can't really do HIIT on a treadmill, it's unsafe and transitions too slow).

That's why I usually start the intervals several seconds before rest period actually ends because of the lag period. It's possible to do it on a treadmill, but I will agree that it is risky because I have almost fallen off going at max speed. I want to take it outdoors, but I'm afraid people will think I'm running for my life.

I take Les Mills GRIT classes a few times per week - they are 30 min HIIT. It's brutal. I can't say that I like it...but I continue to take it anyway because I've noticed a difference in my fitness levels. I keep hoping it'll get easier! But I guess that defeats the purpose, huh?

kcjchang wrote: »

Your intensity is too low. What is your method and duration used to estimate/identify VO2 Max. From your previous posts, you indicated that you have done laboratory tests to determine your lactate threshold (4 mmol L). The VO2 at lactate threshold is not VO2 Max. In world-class athletes lactate threshold typically occurs at 70-80% VO2 Max. In untrained individuals it occurs much sooner, at 50-60% VO2 Max. The other method is to estimate using the formula from American College of Sports Medicine based on the 5 minute mean maximal power or power at the steadier, “pay as you go” pace, from a well-paced pursuit-style effort (e.g. 3 km pursuit race) ignoring the initial spike at start.

robertw486 wrote: »

My all out 100% short term effort would easily exceed 170% of VO2max, but I doubt me or any other average person would do it for many intervals.

That's because one is relying solely on the phosphagen system (~5 seconds of all out effort plus declining output for 12-15 seconds before glycolysis kicks in). Re-phosphorlation will never catch up for the remaining intervals for IE1. This is why downtime (re-phosphorlation) consist of the bulk of the duration for a sprint workouts. Max heart rate is not a limiter on how high the intensity on can go. Same goes with Ventilatory Threshold. The whole point is to tax and maximize one's anaerobic threshold.

I've used several methods to calculate VO2max, and all come up reasonably close. As for intensity, it's metered to 170%, and thus to the protocol, not below it. But that is my point, 170% is not full ability. For people that have no meter, going beyond 170% for even an interval or two would make completing 8 intervals or more much more taxing. I've experienced this as I increased my VO2max to the point where the machine won't read it out in instantaneous reading.

I've never done any lab LT testing, and fully understand that LT and VO2max are two different things.


And having done the Tabata myself, I maintain that it is well within the grasp of many if not most average athletes. Since VO2max is relative to cardio training it certainly won't ever get easier to do, but it's far from any elite level workout IMO.