fat burning works better at low intensity cardio? why?

iwinulose2980

New member
just curious as to why this is. might be a stupid question but wouldnt you burn more with a higher heartrate?

just something ive been wondering for a while
 
I know Lean One has gone over this in the past, you might wanna do a search under his name. Higher intensity will burn more CALORIES, but low intensity will burn more FAT. Correct me if I am wrong here guys!
 
MaNiaK1027 said:
I know Lean One has gone over this in the past, you might wanna do a search under his name. Higher intensity will burn more CALORIES, but low intensity will burn more FAT. Correct me if I am wrong here guys!
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Correct. Aerobic fat burning is most efficient at low intensities.ie between 60% and 70%. Beyond that, you cross the anaerobic threshold where the muscles ability to extract oxygen from the blood to burn fat is reduced so the body automaticly switches to anaerobic energy pathways. You still burn a lot of calories but it mostly comes from glycolisis and lactic acid production. You basicly burn Sugar. Also, the circulating lactic acid inhibits lipolisis.
 
bigpump23 said:
I read one of those once, good work LO
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;) Reffer to the link I posted in the physiology thread. That's where the bulk of my vast* nutrition and exercise knowledge came from.

*That was pure sarcasm. Bobo is way smarter than I am.:D
 
Lean One is right on the money. Basically the higher you get your heart rate the more your body shifts to carbs in relation to fat calories.
 
ok. this all sounds good to me. working a little easier and buring fat not calories for muscles. But in theory would you be able to keep working say for 5-6hrs of low intensity to burn a crap load of fat? or would that kill you :)
And just so i know for sure that 60% is the heart rate right?
any one have a good site to find out ones own 60% heart rate?
 
gabriel said:
ok. this all sounds good to me. working a little easier and buring fat not calories for muscles. But in theory would you be able to keep working say for 5-6hrs of low intensity to burn a crap load of fat? or would that kill you :)
And just so i know for sure that 60% is the heart rate right?
any one have a good site to find out ones own 60% heart rate?
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220-age= Maximum HR Then take Max HR x 60%.
 
gabriel said:
ok. this all sounds good to me. working a little easier and buring fat not calories for muscles. But in theory would you be able to keep working say for 5-6hrs of low intensity to burn a crap load of fat? or would that kill you :)
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If you're talking 5 or 6 hrs straight, That's like a marathon. You know what marathon runners look like right?

Having said that, When cutting(and sometimes bulking) I have done up to 12 1 hr low intensity sessions/week and maintained all my muscle, and in some cases gaining strength. This is with the use of androgens of course. As long as you're training at 65% you're sparing glycogen and protein so your hard earned gains are safe. :thumbsup:
 
thanks jminis

yea all skinny - good point.. not going there.
cool ok thanks man.. I have to drop some fat in 2 months - going to DR :)
havn't been doing very well. getting back on the elliptical now and starting back on the weights a little (shoulder injury - so taking it slow - 4 months off so far)
wonding if any ph may help me as well. have a good few in stock pile,- i know im being sort of a thread hijacker right now so sorry all. pm me if you have any good suggestions thanks.
 
It always seems to come down to aerobic vs anaerobic...fuel of fat vs sugar.

What if you sprint after an intense lift? With using lets say, GXR previous to the workout with relatively no carbs all day?

Wouldnt an intense lift coupled with GXR and relatively no carbs yield an atmosphere where fat would be utilized for fuel during sprinting?

Or am I off here completely?
 
Enigma76 said:
It always seems to come down to aerobic vs anaerobic...fuel of fat vs sugar.

What if you sprint after an intense lift? With using lets say, GXR previous to the workout with relatively no carbs all day?

Wouldnt an intense lift coupled with GXR and relatively no carbs yield an atmosphere where fat would be utilized for fuel during sprinting?

Or am I off here completely?
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Well, the thing you're missing is that doing low intensity cardio for extended durations(ie 45 min to 1 hr) causes cellular changes that result in an increased ability to burn fat. Mitochondrial density increases, fat burning enzymes increase, and your muscles ability to burn fat gets upgraded over time the more consistant you are with this type of cardio.Also, performing cardio for extended periods increases lipolisis releasing more FFAs into the blood because there is a need for it. During a sprint, even if blood glucose levels are low, you will still be performing beyond the anaerobic threshold so your muscles will still be forced to use anaerobic energy pathways anyway.There will be no need to release fat, becuase you will not be able to eficiently burn it anyway(due to anaerobic threshold.) In that situation, your body will have to find glucose somewhere, and if muscle glycogen is depleted,(like in a keto style diet) it will turn to protein breakdown to make that happen. (gluconeogenisis.) A little long winded, but there is no simple explanation. ;)
 
Lean One said:
;) Reffer to the link I posted in the physiology thread. That's where the bulk of my vast* nutrition and exercise knowledge came from.
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Just wondering where is this "physiology thread"?
 
So does it not matter if you do the low intensity cardio on an empty stomach or not? I've heard the body will burn the carbs you have first before using the fat, hence the logic for doing it on an empty stomach. Or will the body not touch the carbs unless you go over 65-70%?
 
Funny thing though, in studies done on people doing various forms of cardio for weight loss, the single greatest indicator of weight loss is total calories burned, regardless of how they were burned.

I don't recall if they measured bodyfat and lean body mass losses or just used the scale though.
 
hypo said:
So does it not matter if you do the low intensity cardio on an empty stomach or not? I've heard the body will burn the carbs you have first before using the fat, hence the logic for doing it on an empty stomach. Or will the body not touch the carbs unless you go over 65-70%?
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With this type of cardio, carbs are a must. Carbs supply the substrates nesesary for the formation of krebs cycle intermediates needed to oxidize fat like pyruvic acid. You're nervous system(brain) also depends on circulating blood glucose for propper functioning. You could get by on muscle glycogen to help oxidise fat in the muscle, but muscle glycogen is not released into circulation to support the brain. So, if your in a fasted state your body will need to get glucose from somewhere to support the brain. It will breakdown protein to get it.
 
An easier way to think about it is this: low-intensity cardio burns a greater percentage of its calories from fat, while high intensity cardio burns more calories over all.

BUT think about the math here. If I only burn 3 calories total but 2 of them are from fat, that's a nice 66% of my calories from fat. High intensity cardio might burn 500 calories, and 250 of them might be from fat. That's only 50%, but it's 250 fat calories.

So if you only look at the proportion of fat to carbs/lean tissue used, low intensity seems better. But when you look at the actual progress you're making, high intensity really gets you there better because the amount of fat burned is so much MORE, even if the percentage isn't.
 
BUT think about the math here. If I only burn 3 calories total but 2 of them are from fat, that's a nice 66% of my calories from fat. High intensity cardio might burn 500 calories, and 250 of them might be from fat. That's only 50%, but it's 250 fat calories.
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Thats why low intensity cardio sessions are done so often and last so long. From my personal experience cardio in the heart rate range of 65-85% should be avoided at all cost. I learned this lesson the hard way, going from 212 to 202, while bf% remained relatively constant.
 
Chippewa said:
An easier way to think about it is this: low-intensity cardio burns a greater percentage of its calories from fat, while high intensity cardio burns more calories over all.

BUT think about the math here. If I only burn 3 calories total but 2 of them are from fat, that's a nice 66% of my calories from fat. High intensity cardio might burn 500 calories, and 250 of them might be from fat. That's only 50%, but it's 250 fat calories.

So if you only look at the proportion of fat to carbs/lean tissue used, low intensity seems better. But when you look at the actual progress you're making, high intensity really gets you there better because the amount of fat burned is so much MORE, even if the percentage isn't.
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waiting on rebuttal, (very interesting)
 
Chippewa said:
An easier way to think about it is this: low-intensity cardio burns a greater percentage of its calories from fat, while high intensity cardio burns more calories over all.

BUT think about the math here. If I only burn 3 calories total but 2 of them are from fat, that's a nice 66% of my calories from fat. High intensity cardio might burn 500 calories, and 250 of them might be from fat. That's only 50%, but it's 250 fat calories.

So if you only look at the proportion of fat to carbs/lean tissue used, low intensity seems better. But when you look at the actual progress you're making, high intensity really gets you there better because the amount of fat burned is so much MORE, even if the percentage isn't.
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I think there's a flip side to this coin, though.

If you burn 3 calories with 2 coming from fat - where does the other 1 calorie come from, isn't this broken down muscle protein? If that's the case then you can say that you only lost 33% muscle protein.

In the other scenario though you lost 50%, or 250 calories, from fat - but didnt you also lose 250 calories from muscle protein?

I'm not that knowledgeable with the nutrition aspect but I suppose it all depends on where the rest of the calories come from.

R6Speed said:
Thats why low intensity cardio sessions are done so often and last so long. From my personal experience cardio in the heart rate range of 65-85% should be avoided at all cost. I learned this lesson the hard way, going from 212 to 202, while bf% remained relatively constant.
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R6Speed - 65-85% is a pretty wide range to avoid, what range do you feel is appropriate for max fat lost while retaining muscle?

Thanks guys.
 
If you burn 3 calories with 2 coming from fat - where does the other 1 calorie come from, isn't this broken down muscle protein? If that's the case then you can say that you only lost 33% muscle protein.
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If you are not glycogen depleted, it will most likely come from glycogen stores. An important thing to remember is that the body does not use one fuel source at a time, it uses all of them all the time, just in different ratios. When you exercise at intensity that puts your heart rate at 65-85% the body's primary source is glycogen and when you become glycogen depleted the body still has to get it from somewhere, and that is from proteins converted to glycogen through gluconeogenisis as Lean One already pointed out. I am still studying this so correct me if I am wrong.

R6Speed - 65-85% is a pretty wide range to avoid, what range do you feel is appropriate for max fat lost while retaining muscle?
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In my personal experience low intensity, with heart rate below 65% has been very effective. For me this just involves walking on a treadmill at 10 degree incline at 2.5mph. HIIT has also been very effective for me. I'll come back and add to this but I have to get to class.
 
Lean One said:
With this type of cardio, carbs are a must. Carbs supply the substrates nesesary for the formation of krebs cycle intermediates needed to oxidize fat like pyruvic acid. You're nervous system(brain) also depends on circulating blood glucose for propper functioning. You could get by on muscle glycogen to help oxidise fat in the muscle, but muscle glycogen is not released into circulation to support the brain. So, if your in a fasted state your body will need to get glucose from somewhere to support the brain. It will breakdown protein to get it.
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This well..not confuses me but goes against what most people suggest for early morning cardio - I understand the science part but what kind of carbs (low gi, I assume) and what percentage should one consume before early moring cardio then? or did I miss something?
 
Pfunk47 said:
This well..not confuses me but goes against what most people suggest for early morning cardio - I understand the science part but what kind of carbs (low gi, I assume) and what percentage should one consume before early moring cardio then? or did I miss something?
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It doesn't require a lot I usuallc consume a protein shake with about 40gn protein and 25 to 30 gm carbs from oats mixed in.1 Hr prior to training.

As for the debate of HIIT vs Low intensity, I'm not going there today. It's been beaten to death here more than once. I don't have the time or patience for this today. :rolleyes: Do a search.

I'm out. :run:
 
Lean One said:
As for the debate of HIIT vs Low intensity, I'm not going there today. It's been beaten to death here more than once. I don't have the time or patience for this today. :rolleyes: Do a search.

I'm out. :run:
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:lol:

The true solution to the endless HIIT vs Low intensity debate - skip cardio altogether!~ :D

I'm down with dragging a sled, or doing squats or deadlifts for time (WSB style 6-10 reps/s, with a weight you can do for between 3-6 minutes) though. I don't consider that cardio, I consider it "conditioning" :thumbsup:
 
I'm not sure how much credibility you assign to these sources, but both Lou Schuler (former editor of Men's Health) and Nelson Montana have told me that doing a high-rate cardio session that lasts shorter is BETTER for sparing muscle than long-and-low. I don't know what their rationale was for this, though. But since I bore easily, I prefer that anyway.

BTW, how many calories do you guys tend to burn per session, according to the readouts on whatever cardio machines you use? (granted, they are not remarkably accurate).
 
exnihilo said:
:lol:

The true solution to the endless HIIT vs Low intensity debate - skip cardio altogether!~ :D

I'm down with dragging a sled, or doing squats or deadlifts for time (WSB style 6-10 reps/s, with a weight you can do for between 3-6 minutes) though. I don't consider that cardio, I consider it "conditioning" :thumbsup:
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6-10 reps/s=second, wehell i can do at least 20 reps a sec.

try bodyweight squats A2G for 2 minutes,
It is hell....purely, most beginners cant do that and women,
no way .
its amazing how much you can do with just your freakin bodyweight.

EX i pull the sled for over a mile with a 45 on it(90lbs)
very good relaxing conditioning
:thumbsup:

a little off topic: I want to make 40-50 feet rail setup in my yard
to pull super heavy weight on the sled, to mimic the tread sled
at WSB. except this you use your arms and your ars.
:cheers:
 
BigP0ppa3 said:
I think there's a flip side to this coin, though.

If you burn 3 calories with 2 coming from fat - where does the other 1 calorie come from, isn't this broken down muscle protein? If that's the case then you can say that you only lost 33% muscle protein.
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As someone else pointed out, the remaining calories comes from gylcogen, provided you arent glycogen depleted.
And that is the biggest problem with fasted cardio. You are already gylcogen depleted (especially muscle I would have thought, liver should still be pretty full) and many people end up training at too high an intensity. I know I did before I bought a HR monitor. Measuring HR when your near max is easy as the blood is (obviously) really coursing through your veins, but when I do low intensity cardio, trying to measure my HR while still on the machine (stair climber normally) can be very hard and wildly inaccurate. Once I bought the HR monitor, I found I had to drastically cut the intensity to keep my HR below 65%. Problem is, cardio then feels too easy so without knowing your "real time" HR, it is very easy (and human nature) to increase the intensity until you start to feel like the cardio is working.


BigP0ppa3 said:
R6Speed - 65-85% is a pretty wide range to avoid, what range do you feel is appropriate for max fat lost while retaining muscle?

Thanks guys.
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In a nutshell, below 65%.
If you plan to venture above this, then make sure you have a pre WO shale/meal to ensure you have plenty of energy to power your cardio session to avoid muscle loss.

There is nothing wrong with hitting the high HR (in fact it is benificial for cardio vascular conditioning), just make sure that you have the pre WO meal/shake and dont try to keep going for too long.
Twenty minutes of moderate/high intensity is long enough to confer both fat burning and cardio vascular conditoning benefits. If you must do cardio for longer (which I doubt many here would feel the need to :D ), then split it up into 2 sessions (AM and PM). Same benefits without the risk.
 
Chippewa said:
BTW, how many calories do you guys tend to burn per session, according to the readouts on whatever cardio machines you use? (granted, they are not remarkably accurate).
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Generally around 500 cals. I never refer to those machine.

...And Nelson Montana it a nut ball. Nuf said.
 
Andrew69 said:
As someone else pointed out, the remaining calories comes from gylcogen, provided you arent glycogen depleted.
And that is the biggest problem with fasted cardio. You are already gylcogen depleted (especially muscle I would have thought, liver should still be pretty full)
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Actually Liver glycogen is used primarily to keep blood glucose levels from falling to low to support the brain and nervous system while you sleep. Muscle glycogen can be full to the brim when you wake up in the morning but liver glycogen will always be depleted.

Remember. Muscle glycogen can only be used by the muscle it is stored in during execise. It is not released into the blood stream to bring up blood glucose levels like liver glycogen.
 
Lean One said:
Actually Liver glycogen is used primarily to keep blood glucose levels from falling to low to support the brain and nervous system while you sleep. Muscle glycogen can be full to the brim when you wake up in the morning but liver glycogen will always be depleted.

Remember. Muscle glycogen can only be used by the muscle it is stored in during execise. It is not released into the blood stream to bring up blood glucose levels like liver glycogen.
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Thanks for the clarification Lean One. I knew it was one or the other :think:
 
Also, some of the HIIT advocates will tell you that cardio will turn your fast twitch fibers into slow twitch fibers, but they fail to realize this won't happen since we already train with weights. This was at least the claim of one dude at my gym
 
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