T Nation

Heart Rate Training for Fat Loss

Hi Everyone,
Recently I underwent a sub max (but only just) VO2 test. The modern day equivalent to a Douglas bag was used which was hooked up to a computer which analyzed the O2 and CO2 that I was exhaling.

On completion of the test I was told that when my heart rate went above 135BPM (beats per minute) the amount of fat that I was burning dropped off sharply; when I saw the graph it showed that the amount of fat being burnt at 140BPM was about a third of that being burned at 130BPM!!

I asked the tester how the programme determined this and he told me that the Weir equation was used to calculate the amount of fat being used.

The reason behind me taking the test is that the company that has developed this software wants to come into our gym and charge our members for this test, our members will then be told what their optimal fat burning heart rate is.

So the question is this,- How accurate is the Weir equation in determining fat kcal’s being used? I must admit that I like many on this forum tend to look at fat loss as Kcal’s in < kcal’s out. I’m sure that I don’t need to spell this out but the way I see this is Kcal’s in is what you put in your mouth and kcal’s out is increasing metabolism through an increase in muscle in conjunction with cardio work, preferably interval training which I believe is more muscle sparing.

If this test is legitimate then part of me is looking forward to ticking over at a 130BPM heart rate but it just doesn’t seem right to me.

Thanks in advance for your input,
B.J

The first trainer of mine did some research into this topic. He used the same sort of test for O2/CO2 and blood tests to determine the % of fat, sugars and carbs metabolised during various levels(varied speed, incline) of cardio(treadmill). He was concerned with trying to find the ‘optimum’ settings to use to burn the highest % of fat, since during exercise the human body burns different %s of all three types of cals.
His research noted that the highest % of fat burned was with the treadmill set at 5 inc, with a speed of 3.5. mph, with this % becoming smaller in comparison to the others on either side of these settings.
He also used a formula to determine the optimum heart rate to target for fat metabolism. It turned out to be 130bpm me. Using the data from the research, I started using them for my treadmill work initally.
These settings barely get a raise out of my resting heat rate, so I had to conclude that those setting might have meant that ‘he’ burned the most fat at them. He was about 5’ 8, 250+lbs… an ‘unnatural’ competitor :wink: (not that there is anything wrong with that)… and so, for me the optimum would be settings that were higher. I seemed to get greatest success with an inc of 9 and a speed of 4.2mph.
This does not directly answer your question regarding the Weir formula, but it does support your observation that you were getting greater benefit from 130bpm as opposed to the 140bpm.
Peace.

These numbers are fairly accurate as to the energy source used during exercise.

However, one of the main benefits to performing intense exercise is the calories burned afterward due to elevated metabolic rate. Most people don’t burn many calories during their typical 20 to 30 minutes of cardio.

imo the amount of fat burned DURING exercise is irrelevant and charging people for a “find your fat burning zone” test sounds like a scam.

[quote]MookJong wrote:
imo the amount of fat burned DURING exercise is irrelevant and charging people for a “find your fat burning zone” test sounds like a scam.[/quote]

I HAVE to reply to this ‘Mook’…so, the 2 hours of cardio that a competitive friend of mine does daily when preparing for a competition is wasted? Imagine her surprise when I tell her… She just won her division for the Canadian Bodybuilding championship. The time she could save… and she has you to thank for it… You are a saint…
Either that or you have no idea what the fuck you are talking about…
It only takes a bit of experience and a bit of trial and error to find the best ‘fat burning’ setting for yourself.
I think you are just slightly misguided by discounting the experiences recounted here.
I am not surprised that a company would be established to try to profit from this. If someone was studious enough and looked at the literature, it would be possible to do it yourself. It would also entail doing some personal experimentation, apparently not a strong suit for most on this continent.
This is, of course, the landmass with such posters as the winner who was recently complaining that he could not find many articles related to fat loss on this site.
Please, reconsider your statement.

[quote]mowgli1959 wrote:
MookJong wrote:
imo the amount of fat burned DURING exercise is irrelevant and charging people for a “find your fat burning zone” test sounds like a scam.

I HAVE to reply to this ‘Mook’…so, the 2 hours of cardio that a competitive friend of mine does daily when preparing for a competition is wasted? Imagine her surprise when I tell her… She just won her division for the Canadian Bodybuilding championship. The time she could save… and she has you to thank for it… You are a saint…
Either that or you have no idea what the fuck you are talking about…
It only takes a bit of experience and a bit of trial and error to find the best ‘fat burning’ setting for yourself.
I think you are just slightly misguided by discounting the experiences recounted here.
I am not surprised that a company would be established to try to profit from this. If someone was studious enough and looked at the literature, it would be possible to do it yourself. It would also entail doing some personal experimentation, apparently not a strong suit for most on this continent.
This is, of course, the landmass with such posters as the winner who was recently complaining that he could not find many articles related to fat loss on this site.
Please, reconsider your statement.

[/quote]

Thanks for the responses guys,
I believe that Mook was just emphasizing that the increase of the metabolic rate is the most important aspect of fat loss, an opinion that I agree with.
Mowgli, if your friend is a bodybuilding champion then she would have an appreciable amount of muscle revving up her metabolism so that her 2 hour cardio sessions are all the more effective.
Going back to the chap you knew who trained at low intensities; do you know how effective his training was?
And to anyone else; can you add any opinions as to whether this analysis of heart rate along with O2/CO2 actually does target fat loss effectively?
Many Thanks BJ

Different strokes for different folks.

But in general:
with more intensity, more calories are burned
with more intensity, a lesser percent calories burned are from fat

Still more calories can be burned from fat at higher intensity because the overall energy expenditure is so great. And add on to that the metabolic effects.

I used to do a lot of moderately intense cardio (70-80% MHR) but cardio nonetheless. I stayed pretty fat. Now I do less overall time (about half as much) but do interval training BALLZ out. I have dropped more fat and maintained size and strength. Cadio sucks ballz for me. Intervals rule.

So, here’s my point: f*ck that calculation - get your heart rate UP there - get some results.

Bastard F*ck Guy

http://t-nation.com/readTopic.do?id=461325

John Berardi’s getting in shape

Long cardio can burn a lot of calories, but not as many as the elevated metabolism from anaerobic intervals or Tabata sprints!

Besides, I recall reading somewhere that very long, slow cardio (like the long runs during marathon training) increases cortisol to the point where the body burns muscle and stores fat preferentially.

Tabatas are more fun: Warm up for five, go for five, cool down for five, done in fifteen minutes max.

How long does interval training need to be for good fat loss. The actual time of high intensity interval training not including the warmup and cooldown

[quote]extremepumps wrote:
How long does interval training need to be for good fat loss. The actual time of high intensity interval training not including the warmup and cooldown[/quote]

Man I wish I knew the scientific answer to that. As I stated, my results have been great. Basically here is what I have been doing:

10 minutes of intervals takes me 15 minutes - ie I haul ass for 60 seconds and rest for 30 or haul ass for 90 and rest for 45

I do one 10 (15 total) minute session prior to lifting and then another similar session after

I prefer the stair stepper or eliptical machine - both are used at max or near max resistance or rate

Sometimes I’ll do a 15 min session (22 total) if I feel like the bionic f*cking man

Sometimes I’ll do only a 5 min session

I drop the intensity on the session just prior to a squat or deadlift workout

(It is amazing how easy post squat interval training can seem)

I have never done more than 30 (45 total) in one workout - that would be insane, and I have incredible endurance ability and a high tolerance for muscle fatigue induced pain

Recently I have been dropping the post lifting session and just doing the initial session

As I also do short rest intervals when lifting of 30-90 seconds, my entire weight session has basically turned into interval training

Still I like the initial session to warm-up and get ready to move some metal

To increase intensity, increase the work:rest ratio

to start, you may want to use a 1:1 ratio - i’d suggest 10 minutes with a 1:1 ratio to start - go 30 sec on and 30 sec rest for 10 minutes - tweak it up from there

Bastard F*ck Guy

[quote]extremepumps wrote:
How long does interval training need to be for good fat loss. The actual time of high intensity interval training not including the warmup and cooldown[/quote]

did you see this???

http://www.t-nation.com/readTopic.do;jsessionid=5C5589D938330445AD8D3C83A94CE70B.ba13-1?id=459271

To my best knowledge the Weir equation is a physics equation related to the Bernoulli equation that calculates flow rates for air, fluids, etc. usually in calculating flow rates in rivers. So, this tester seemingly had no clue what he was talking of. There are a number of gas analyzers on the market these days that measure O2 and sometimes CO2 to determine O2 consumption and either a predicted Vo2 max from a submax test or a VO2 peak if the person went to exhaustion (certain criteria have to apply to call it VO2max). Any way, most of these software packages used on these units use what is called the Wasserman equation to pick the Lactate threshold (or sometimes erroneously called the anaerobic threshold), that point when lactate begins to accumulate in the blood and you begin to experiencing some of the fatigue effects of lactic acid. In addition, some of these if measuring CO2 will also give an RER (or Simply R value), which is an O2 to CO2 ratio. This ratio gives a good picture of what energy substrate is being used to fuel the activity. For example, theoretically if we were burning all fat the RER would be around .70 and if burning all carbs would be 1.0 or greater (although we really never burn exclusively one or the other it is always some mix). So, these companies market these analyzers and testing services to fitness clubs so that can they can identify for their members their ultimate fat burning zone by measuring HR and determine what the HR is at the point when fat utilization is at its highest. The problem is there are two ways to express energy substrate utilization: either as relative (a percentage) or as an absolute. Most of these express it as a percentage, which can be very misleading. Here is an example.

Lets say we have two identical people (clones). Both are going to exercise for 20 minutes. Clone A is going to walk for 20 minutes and burns 100 kcals while clone B is going to run for 20 minutes and burns 200 Kcals. We are going to use our VO2 analyzer to measure O2 and CO2 and therefore RER. Lets say that we measure the RER of clone A to be around .82 and clone B around .90 (realistic numbers). A RER of .82 would mean the person is using about 70% fat and 30% CHO (carbs) and an RER of .90 would be about 40% fat and 60% CHO. Aha, you say, there it is, the lower intensity burned more fat that the high intensity. But wait. Lets do some math.

Clone A

Calories 100
% fat 70
% CHO 30
Kcals of fat 70 (100Kcals x .70)
Kcals of CHO 30 (100 kcals x .30)

Clone B

Calories 200
% fat 40
% CHO 60
Kcals of fat 80 (200 kcals x .40)
Kcals of CHO 120 (200 kcals x .60)

So, we see that although clone A burned a higher relative (%) of fat clone B burned a greater absolute amount of fat and greater number of calories. A number of studies have shown that caloric cost becomes more important than the substrate contribution.

What is the take home message? Higher intensity work will burn more calories in a shorter amount of time and in many cases the absolute amount of fat burned will be greater although the percentage is lower. In addition, the EPOC (excessive post exercise oxygen consumption) will be higher with higher intensities. This is just a fancy name for the elevated O2 consumption and therefore caloric cost once the exercise is over, which can be elevated for many hours.

Problem is many people cannot maintain higher intensity exercise for any significant period of time, thus the overall caloric cost is not that high. Enter the interval training model, as already mentioned by a few people on this thread. This allows us to have higher intensity bouts separated by recovery periods and can be very effective in fat loss (much more effective than mindlessly walking on a tmill for ever and it seems less tedious because you always having to think about the change for the next work or rest interval and you feel like you have accomplished more due to the higher intensity ? there are many benefits). The cool thing is any one can use interval training. We always associate interval work with high intensity which some might not be able to do. But it does not have to be high intensity, only HIGHER intensity separated with the rest interval. The simplest example is walk 100 meter then jog (or even just walk faster) for 100 M. Or using HR, 70% Hrmax for 2 minutes then 55% Hrmax for 1 minute. The combinations can be endless.

Great post, lawakua. A theory is that caloric expenditure may be more important than caloric intake for lipolysis. It seems true, anecdotally. I recall that every time I have been active I have stayed fairly lean, regardless of caloric intake. Like the saying, “You can’t save yourself rich.” Thoughts?

Lawakua
Many thanks for the reply, when I did a google search before my original post, most of the entries were to do with water -although some were about a seperate equation to do with energy expenditure.

Having said that, I believe that you and some of the other posters are correct about total kcal expenditure, as opposed to % of kcals burned. Personal observations also back this up; over the 20 years that I’ve seen bodybuilders, athletes, and recreational trainers exercise the indivuals who kept themselves in shape were/are the ones who 1, have a good amount of muscle mass and 2, do short, sharp bursts of interval training, and guess what? they also consumed a good diet.

Looking at all the responses I’ve recieved, I don’t see how this test can be that helpful to people looking at controlling bodyfat, and unless there’s some strong evidence that’s about to be presented, then I’m going to recommend that we refuse this company access to our gym.

Many thanks to everyone for their help.
Regards BJ

[quote]dookie1481 wrote:
Great post, lawakua. …[/quote]

Affirmative - nice post. lawakua please find my personal clone so i can put him (dude tell me it’s a guy) through some totally f*cking insane programs.

BFG