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Every gym I’ve ever been in has had one of those heart rate charts on the wall showing me where my heart rate should be depending on my goals for that exercise session. To burn fat, then my heart rate should be X beats/min, but to improve my cardiovascular abilities then it should be Y beats/min.
These charts have always given me fits. My number one goal has always been to burn fat, but my target heart rate (THR) for fat burning is so low that I don’t feel like I’m working out when I’m in that zone. So I get bored, start working harder, and leave my ideal fat burning zone–according to the chart anyway.
I’ve always been kind of a gadget guy, and right now I’m a sucker for fitness gadgets. I just spend half an hour looking at electronic body tape measurers and electronic heart rate monitors. I already have the chest strap for the heart rate monitor that came on my treadmill and it works on the machines at the gym so I have the ability to accurately train in specific heart rate zones. But I don’t really know much about the zones I’m supposed to be training in.
In his book, Precision Heart Rate Training For Maximum Fitness and Performance, Edmund Burke sums up the research on heart rate zone training AND provides some work out plans for athletes of different abilities. I found the book extremely helpful for clearing up my major question about heart rate training. Does it matter if my heart rate exceeds the typical weight loss heart rate zone?
The simple answer to this question is a resounding “no!”
But let me provide a few of the details that led me to the answer. Traditionally, the typical “weight loss/fat burning training zone” is between 55%-65% of your maximum heart rate (MHR) as determined by the common formula of 220-your age. My MHR is somewhere around 186 bpm which means that my fat burning training zone should be between 102 and 121 bpm. While in this zone, approximately 50% of my calories burned will come from fat, and the other 50% will come from glycogen stored in my muscles.
In contrast to the weight loss/fat burning training zone is the “aerobic/cardiovascular” zone. This zone is defined as being between 65%-85% of your MHR. Therefore, my aerobic/cardiovascular training zone should be between 121 and 158 bpm. While in this zone, approximately 33% of my calories burned will come from fat, and the other 67% will come from glycogen stored in my muscles.
It sounds like I should be training in the lower zone if I want to burn more fat calories, right? Well, let me explain the math to you. If you exercise in the fat burning zone for 30 minutes you can expect to burn approximately 220 calories (depending on your choice of exercise). 110 of those calories burned (50%) will be fat calories. If you instead exercise in the cardio burning zone for 3o minutes, you can expect to burn approximately 330 calories (again, depending on your choice of exercise). 110 of those calories burned (33%) will be fat calories. Realistically, 30 minutes of exercise burns the same amount of fat calories regardless of your training zone. But, if you’re able to bump up your heart rate for those 3o minutes, then you’ll burn a 100 more calories. Burke sums it up best:
If your goal is to get leaner, the bottom line is to cycle, swim, or run at the highest intensity that you can maintain for 30 minutes or longer. You need not give consideration to the type of fuel burned during an activity to guide your exercise prescription. Until proven otherwise, when it comes to weight loss, a calorie burned is a calorie burned, regardless of its origin.
J.D.
9 responses so far ↓
1 brad // Jan 24, 2008 at 4:20 pm
Gina Kolata has interviewed quite a few exercise scientists for her books, and they all conclude that the “fat burning zone” is a myth. There’s a section on this in her book “Ultimate Fitness” (a great read by the way), in which she comes to the same conclusion that you cite from Burke above: a calorie burned is a calorie burned, no matter what its origin. In fact in her recent Q&A series in the NY Times, Kolata says this: “The only thing that matters is the total number of calories you burn during your workout. The fat burning zone is a myth. So if an interval workout and a steady state workout require the same total effort, they are equivalent.”
2 greenman2001 // Jan 24, 2008 at 8:15 pm
You’re definitely reading the right stuff, Mac. Burke is a professional. The South Beach Diet doesn’t offer quite the same insight, does it?
Atheletes use heart rate for very different purposes than dieters. “Low and slow” is the way endurance atheletes build endurance — a sustained, low heart rate enables the body to grow more blood vessels into muscles (including the heart) to keep them functioning during sustained exercise. This is why slow exercise, like walking, is encouraged after a heart attack: it helps the heart to grow new blood vessels to replace those damaged and killed during the heart attack.
Your impulsivity is a real liability in this game, Mac. If you push too hard at the early stage, you won’t have the physiological foundation to support vigorous regular exercise in the future. Without the foundation of blood vessel penetration, you set off a chain of events: you get tired quickly and easily, it takes longer for your muscles to recover, you have more muscle pain the next time you exercise, and it gets that much harder to motivate yourself through increased levels of pain and fatigue that have an earlier time of onset. A professional athletic coach would be slowing you down at this early stage, and then — a couple of months from now — whipping you along the way you naturally might prefer.
A great book to read that touches on this and other fascinating aspects of serious training is Bill McKibben’s Long Distance, about the year he spent training with an Olympic skiing coach for cross-country skiing competitions.
Can you share with us some details of your exercise regimen?
3 SmarterFitter Blog » Blog Archive » Heart rate training day 4: a pleasant awakening… // Jan 25, 2008 at 1:42 am
[…] pointed out that it looks like Get Fit Slowly is thinking about heart rate too and particularly in relation to fat burning. He concludes that for […]
4 James Lemoine II // Jan 25, 2008 at 6:15 am
Those heart rate charts are very general and can be confusing. They don’t match what I need to do either.
Training with a heart-rate monitor can be very beneficial. When I started doing so my weight loss results were much better as the heart rate monitor ensured my cardio routines were as intense as they needed to be.
When I started out, keeping a 140 bpm rate did not take much effort. Once I started adapting to the exercise (a couple of weeks), the same physical effort only allowed my heart rate to be 130 bpm. I had to increase the intensity to get back up to 140.
Also when you are mentally drifting off during a cardio workout (helps the time fly), you may be slowly decreasing your intensity and not even realize it. Having a heart rate monitor beep at you when you drop out of a zone can be very handy…
5 Brigid // Jan 25, 2008 at 7:21 am
The way it’s been explained to me - and anyone can correct me if I’m wrong…
If you are burning glycogen from your muscle during these more intense workouts - you are reducing your muscle mass and henceforth lowering your metabolism. If you can keep your metabolism reved up, it’s going to give you some leeway on the food side of things.
I’m not saying that you shouldn’t train in the cardio zone. It’s actually very important - however it should be mixed up with longer, low intensity workouts and weight training. If you alternate between these three types of workouts, it should serve you well and protect you from injury. Remember to give yourself one day of rest each week as well.
I know first hand the problems with overtraining. You bust your butt and nothing happens except that you start getting sick. No one’s immune to this so don’t try to fool yourself into thinking more is always better.
Keep up the great work!
6 Asithi // Jan 25, 2008 at 11:48 am
One thing I find very helpful about using a heart rate monitor is that it gives you a better idea of how much calories you are burning with exercise. I know that I cannot burn off a Snickers bar in 30 minutes. It takes closer to 40 minutes for me. I am starting to understand the correlation between food intake and calorie expenditure with exercise the longer I use my heart rate monitor. And I am happy to say that sometimes I make better food choices because I know that I will have to workout X minutes in order to break even with the junk food I want to eat.
7 Anne Keckler // Jan 26, 2008 at 1:04 pm
@ Brad: The fat burning zone isn’t a myth, in that it does actually exist. You do actually burn more calories from fat when your heartrate is in that zone than you do otherwise. The problem with this is that, on an hour-by-hour basis, the fat loss will be about the same. Intervals are somewhat different.
@ greenman2001: The only way I know of to grow new blood vessels is through gene doping. This involves inserting a gene into tissues. It is generally used to benefit the elderly who suffer from peripheral arterial disease. I’ve never heard of cardiovascular exercise inducing new blood vessel growth.
@ James Lemoine II: I agree that a heartrate monitor can be useful at times, but one can also use the rate of perceived exertion (RPE) to determine intensity, especially if there are no heart problems.
@ Brigid: Burning muscle glycogen does not mean that you burn muscle mass. Glycogen is simply a sugar.
@ Asithi: Knowing how many calories you are burning when you exercise is a little more complex than this. For a detailed explanation of how to measure calories burned, see my web page at http://www.annekeckler.com/archives/5
As for “a calorie burned is a calorie burned,” that is true up to a point. When you are first beginning to lose weight and get in shape, it’s really enough to eat a little less and be a little more active. Eventually, though, you might want to become more efficient with your workouts to optimize fat loss, while retaining lean mass.
Good luck! I’ve subscribed to your feed and I look forward to reading this blog. I’ve enjoyed your Get Rich Slowly blog for quite a while now.
8 Tom McNicholas // Jan 27, 2008 at 8:15 pm
I’m following this plan, its working well for me. I set my intervals for every 8-10 workouts.
http://www.coolrunning.com/engine/2/2_3/181.shtml
Good luck!
9 greenman2001 // Jan 29, 2008 at 8:02 pm
Anne: I’ll quote from Long Distance by Bill McKibben:
“Endurance training, in essence, aims to make the [heart] work better. Instead of beating seventy times a minute at rest, about normal for most folks, the heart of a well-trained athlete may thump only forty-five or fifty times a minute when she’s resting. Her inert body requires the same amount of blood; it’s just that with each beat her heart pushes far more of it through the veins….The idea [is] to lay a foundation — to literally change my body so that its network of capillaries would grow more dense, something that happens most easily at [a]gentle pace. Then, when the time came for intense training and racing, my powerful heart would have the plumbing network it needed to flush the lactic acid out of my muscles and supply fresh new blood rich with energy.”
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