fat burning works better at low intensity cardio? why?
- 02-24-2005, 02:30 PM
- 02-24-2005, 02:45 PM
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!
02-24-2005, 02:57 PM
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.Originally Posted by MaNiaK1027
02-24-2005, 02:58 PM
02-24-2005, 03:14 PM
02-24-2005, 03:16 PM
02-24-2005, 04:20 PM
Reffer to the link I posted in the physiology thread. That's where the bulk of my vast* nutrition and exercise knowledge came from.Originally Posted by bigpump23
*That was pure sarcasm. Bobo is way smarter than I am.
02-24-2005, 04:26 PM
02-24-2005, 05:01 PM
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.
02-24-2005, 05:37 PM
02-24-2005, 06:05 PM
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?
02-24-2005, 06:15 PM
02-24-2005, 07:49 PM
If you're talking 5 or 6 hrs straight, That's like a marathon. You know what marathon runners look like right?Originally Posted by gabriel
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.
02-24-2005, 09:10 PM
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.
02-24-2005, 10:13 PM
wow so since im 24 that means my target heart rate has to be right around 124 bpm? man ive been waaaaay over.
02-24-2005, 10:25 PM
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?
02-24-2005, 10:55 PM
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.Originally Posted by Enigma76
02-25-2005, 12:36 AM
Just wondering where is this "physiology thread"?Originally Posted by Lean One
02-25-2005, 01:34 AM
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%?
02-25-2005, 02:07 AM
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.
02-25-2005, 06:22 AM
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.Originally Posted by hypo
02-25-2005, 09:48 AM
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.
02-25-2005, 10:42 AM
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.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.
02-25-2005, 10:52 AM
02-25-2005, 11:13 AM
I think there's a flip side to this coin, though.Originally Posted by Chippewa
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 - 65-85% is a pretty wide range to avoid, what range do you feel is appropriate for max fat lost while retaining muscle?Originally Posted by R6Speed
02-25-2005, 01:13 PM
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.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 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.R6Speed - 65-85% is a pretty wide range to avoid, what range do you feel is appropriate for max fat lost while retaining muscle?
02-25-2005, 04:20 PM
Originally Posted by Lean One
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?
02-25-2005, 05:39 PM
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.Originally Posted by Pfunk47
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. Do a search.
02-25-2005, 05:43 PM
Originally Posted by Lean One
The true solution to the endless HIIT vs Low intensity debate - skip cardio altogether!~
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"
02-25-2005, 06:30 PM
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).
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