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Heart rate fat burning percentage

Posted: Fri Jun 06, 2008 4:00 pm
by Manofsteel319
Ok HIIT plus diet and weight training is the most effective way to burn fat or is it?

I believe that but my gf is always one to push back on supposed truths. She says that she needs her heart rate to be in the active fat burning range not too high but just like 140 bpm.

At her gym she read something that by elevating her heartrate to higher than that range would instead burned consumed carbs instead of fat. I know the whole Idea of fat burning isn't to actually burn the fat but to burn calories and then make the body have to rely on the fat there fore in fat loss.

What is the truth in that? Does that slow running at a slow pace burn fat? and does fast HIIT immediatly hit the carbs and not aim for fat burn? Thing is I put two and two together and get 4 she questions the 4 answer. LOL.

By the body supposedly burning carbs that in turn is burning calories which in turn would eventually burn fat. Am I right or did I get something wrong along the way?

Posted: Fri Jun 06, 2008 4:12 pm
by brook011
There is no fat burning zone, I learned this a few months back. It sure would be nice if you didnt have to work as hard to burn your fat off, but HIIT training induces an anaerobic phase like weight lifting, so your burned fat is for a much much longer period of time than just the seated work in the fat burning zone. Since it also builds muscle as well, you're much more likely to get a shredded look from the muscle built. I wish I understood more about this, but I know others on the board will probably chime in for you on a more detailed and proper explanation.

Posted: Fri Jun 06, 2008 4:17 pm
by Manofsteel319
I just have confusion on the topic because the woman threw a monkey wrench at me. Supposedly fat burning zone is true. It says it at her gym I said her gym people were on crack she said " i knew youd say that " well yea. I'll do some research and see what happens.

Posted: Fri Jun 06, 2008 7:50 pm
by stuward
Higher intensity training will burn more fat than in the "fat-burning" zone, just a lower percentage. Your right in that you burn more calories at higher intensity and that's what's important. However, people are able to sustain longer workouts at low intensity than at high intensity. Tell her that it's total calories that count and she can burn them a lot faster if she runs faster.

It's interesting that a few sprints 3 times a week works your heart as well as 1 hour of running 5 times/week. Sprinting also doesn't consume your muscles like running. That's probably not relevant for your gf but for you, that's the way to go.

Posted: Fri Jun 06, 2008 8:05 pm
by pdellorto
What the other guys said. There is a zone where more fat is burned proportionally than other fuel sources, but so what? Overall, more total fat is burned with higher intensity exercise. If I burn 100 kcals of fat in my fat burning zone out of 150 total kcals burned (numbers made up) vs. burning 450 total kcals burned and 150 kcals of fat burned at a higher intensity, which is better for fat loss? The second is much less efficient at burning fat, but overall it's more successful.

Here's some actual numbers: ... 22601a.htm

What it boils down to is what I said - you burn a higher percentage of fat at lower intensities, but burn more fat overall at higher intensities. Also, at higher intensities you also promote more post-exercise consumption of calories, better cardiovascular health, etc. The myth of the "fat burning zone" is that there is one, but that it matters.

Posted: Fri Jun 06, 2008 10:34 pm
by Jungledoc
Yeah. What everyone else said.

When you burn calories, it's not like there are particular calories floating around that you can burn selectively, some from fat, others from elsewhere. You use up so much fuel. If you do it slowly, there is time for the body to convert some fat into fuel to burn. If you are burning fuel slowly enough, most of what you burn can be accounted for by mobilized fat stores. (So I think that the ultimate "fat burning zone" would be sleeping in bed!) But if you burn faster, the body has to get it from somewhere, and will utilize glycogen and glucose.

If you don't replace the glycogen and glucose, the body will go on converting fat to take it's place. According to what I've read, HIIT amplifies this effect.
If at the end of the day, you have burned more calories than you have taken in, the balance in the fat account will be lower.

Posted: Sat Jun 07, 2008 6:23 am
by TimD
John, pretty much what the others have said. But there are diehards out there. Here is a good take on it complete with references, "The heirarchy of fat loss" by Alwyn Cosgrove.
It's completewith referenced studies. To paraphrase what Cosgrove implies, but doesn't come outright and say, is that the "zoe" thing discussed above is the least effecive, but if you like doing the ol' Hamster Dance, go for it. Just don't expect to burn off a lot of fat in the proces.

Posted: Mon Jun 09, 2008 10:34 am
by Manofsteel319
ok I knew I was right. It was all about calories burned. She likes her gym so she assumes her gym is right about everything. They weren't necessarily wrong just not as right as me and my fellow ers.


Posted: Mon Jun 09, 2008 11:03 am
by brook011
That leaves me with a question. Should HIIT be the only kind of exercise you do? I currently do that 5 days a week usually. Should I be splitting it with standard aerobics?

Posted: Mon Jun 09, 2008 11:10 am
by Manofsteel319
Depends on what you want to do. If your goal is weightloss/fat loss it wouldn't hurt. Don't run yourself into the ground though.

Posted: Mon Jun 09, 2008 11:12 am
by KPj
Manofsteel319 wrote:They weren't necessarily wrong just not as right as me.
Possibly one of the best quotes i've heard recently. :lol:

* makes note to steal *

"yes, honey, I agree with you. It's not that your wrong, it's just that...well Your not as right as me"


Posted: Mon Jun 09, 2008 11:16 am
by Manofsteel319
Yea .....she yells at me hilarious.