Burning Fat

Mysk

This may be a stupid question, but when I go to they gym most of the cardio machines have a small graph of heart rates showing, e.g. what the maximum bpm should be at whatever age you are.

One of things I've wondered about is that from about 65% to ~75% is titled "fat burning" whereas above that to 90% is "cardio training".

I was wondering if at the higher levels you are both burning fat and training cardio, or just training cardio? My current goal is to lose weight which I put on after a particulalry unpleasant stomach bug rather than improve my stamina, which I'm happy enough with at the moment.

On an unrelated question, is there anywhere in Dublin where you can bulk buy protein bars reasonabley cheap? Various health stores seem to be extremely expenxsive, one of the things a spell in the US has spoiled me with..

hunnymonster

This is the simpliest explaination I could find.

http://www.multisportracing.com/health.shtml


You burn fat no matter what your heart rate, but you burn a higher percentage in the 60-70%MRH range and because it's easy exercise you're more likely to be able to keep going longer and so use more fat for fuel in total.


btw, the predicted maximum heart rates based on age are a load of c**p. Mine is over 20 bpm out!

Mysk

Heh, I didn't think that you wouldn't burn fat at all, but looking at that it does seem that 60-70% is most effective. Damn, I prefer going for it. Oh well.

hunnymonster

the two major problems I see with the 60-70% is that
a) you gotta be out there a long time to get significant results. Depending on your goals this might not be compatable. Forexample, I doubt there is a BB'er out there who routinely runs marathons
b) once you stop, you stop. Something like HIIT has longer lasting effects from what I understand.*












*but I'm not an expert and by October this year 80% of my training will be < 75% but that's for a specific event.

Hanley

hunnymonster wrote:

the two major problems I see with the 60-70% is that
a) you gotta be out there a long time to get significant results. Depending on your goals this might not be compatable. Forexample, I doubt there is a BB'er out there who routinely runs marathons
b) once you stop, you stop. Something like HIIT has longer lasting effects from what I understand.*

From what I've read/heard that seems to be a good explanation.

However I did not know that the 60-70%MHR range is recommended solely because you're more likely to keep going for longer. Is that not basically saying the duration rather than the intensity is paramount? (self evident I know, but just thinking out loud really!)

Guess you learn something new every day!

Mysk

Using a little bit of logic if I had some time on my hands would an initial 60-70% followed by a session of HIIT make sense?

hunnymonster

It's not soley because you're out for longer. It's a combination og higher percentage of your fuel calories coming from fat and doing that for longer. My understanding of it is outlined below.


For example if you use 700 kCal an hour running at 6 mph (HR 65%) and 85% of these come from fat (this will also depend on other factors besides HR such as when you last ate) you will have used 595 kCal from fat. Each gram of fat had about 9 kCal so you have used approx 66g of fat for this run. Note however that you have also used 700-595 = 105 kCal from other sources. Hopefully this will be muscle glycogen from well fueled muscles but if you're not careful the proteins in the muscle will be broken down and used for fuel. THis is not what you want.


Suppose you now run faster. Say at 85% but you only do this for 30 minutes. This might expend 900 kCal an hour (so 450 in 30 min) but a lower percentage (for arguements sake 50%) will come from fat. you're still burning more calories per unit time but only 225 from fat (i.e. 25 g ) Now the other 225 has to come from somewhere. Again muscle glycogen or the muscle themselves.


All these numbers are just to illustrate a point.

cavanmaniac

Interesting debate.

I was doing pretty intense cardio three times per week for years and lost alot of weight but was struggling to put on any muscle mass from a fair amount of weights sessions. My cardio generally took me into the 90%+ range for about 20 minutes a session and at one stage I was doing that and another 20 mins cardio on a different machine at only a slightly lower rate.

It was satisfying to run off a pile of body fat initially but then I was struggling to tone up to any noticeable degree so now I'm being told to do 25 mins cardio per session at no higher than 75% heart rate.

I must admit it feels very, very weird by comparison to my traditional workouts, to finish the 25 minutes and be barely out of breath or sweating but I'll stick with it to see does it keep the body fat off and help me build more muscle on the weights.

Degsy

I found quite a lot of weight fell off when i started hillwalking on the treadmill immediatly after weights.Finish weights,neck a protein and glucose drink and then a 30 minute brisk walk at around 7.4 kph at a varying incline.I found this worked much better than a thirty minute jog not least because you tend to be less tired and more likely to want go after a day in work.