SD on heart rate training zones

Factual Questions
1

I recently started using a Polar FT60 heart rate monitor. Its literature, and a lot of spaces on the web, seem to describe heart rate zones as ‘losing weight’, ‘improving fitness’, and ‘maximizing performance’.

Are these just sops and warm fuzzies to make me feel comfortable exercising within a zone? That is, if the driving force behind weight loss is calories expended (with a nod to various biological and nutritional differences), aren’t the higher ‘improving fitness’ zones better for losing weight than the lower zone? I ask because some pages explain the differences as the type of energy each zone uses or the source of that energy.

For example, here’s Polar’s description of three zones:

That’s a relatively light treatment. In other places, it all but says that the lower zone is better for losing weight—the lower zone burns fat, while the higher zone burns (?profit?), giving the impression that if weight loss is the goal, using a HRM to avoid getting too intense will yield better results (weight-loss wise). But I’m having trouble accepting that. If I can huff and puff my way fairly comfortably in the higher zone, shouldn’t I stay there for the majority of a workout? Won’t I get all the benefits of the lower-intensity training and then some?

(As a bonus question, now that I’ve taken their ‘fitness test’ measurements, is the HRM’s calorie counter fairly accurate to within ten to twenty percent of what it says? That is, if it says I expended 800 calories after an hour on an elliptical, is it safe to assume that the actual expenditure was between 700 and 800?)

2

Ignore the calorie count, it’s an approximation at best.

You’re right that working at a higher level burns more total calories. The “fat-burning” level is out dated thinking.

It is correct that your fat burn % rises as fitness improves though that’s only a concern for very long workouts of 1-2 hours.

Depending on your starting fitness, you might want to start at the lower intensity to “break-in”.

3

Rrunner pat is correct that the “fat burning” mode is outdated.

What it is is a training mode.

Here’s an interesting bit, they did at Brown Univesity and duplicated at Johns Hopkins.

To improve your heat they found you need to work out at 85% of your theoretical maximum heart rate, 60 minutes a day, five days a week.

What was so interesting was that if you worked even a bit less, like 50 minutes or did it for four instead of five days, there was NO marked improvement in your heart.

That seems to be the cut off point.

Also interestingly they found the more and more fit you get, the more you have to do to keep it up. For instance, they found Olympic caliber athletes got NO improvement in their hearts at 85% of their theoretical maximum. They had to increase it to 95% of their theoretical maximum.

This is because an Olympic caliber athlete was in such good shape his/her body demanded more.

But the thing is you want to run to put your body into a fat burning mode. I have six pack abs. People ask me how I got it. I run. That is the way to get it. Abs are actually easy to work. Sit ups, crunches, twists, will give you a great set of abs. The problem is for most of us, they’re covered up by fat. I happen to be one of those people who store all their fat in their gut.

I had to run, run, run to get it off.

The thing is your body takes the line of least resistance. It always does this. Your body normally burns carbs, which have 4 calories per gram. But let’s say you run and run and run. After a while your body says, “Whoa, wait a minute this is stupid, we’re burning carbs. Why not use body fat”? Fat has 9 calories per gram, so you see it’s a much more efficient fuel.

This is the reasoning behind it. If you go slower you’ll run longer. The longer you run, the more apt your body will switch and use body fat as fuel.

It varies when your body does this. You can tell personally by getting your second wind. Have you ever run and felt like you can’t go on and suddenly you get your second wind? And can start right back up. That is your body switching to fat as fuel.

For the average person this happens as 20 - 30 minutes. Your time will of course vary.

And when I say running what I really mean is aerobic exercise, you can run, job, use a stairstepper or even swim, so long as you get the heart rate up

4

Say* what*???

Sorry, but a link here is required as that is so contradictory to everything else in the literature and recommended by sports medicine experts.

85% of maximal heart rate and above is the anaerobic range. Some sources, like The Cleveland Clinic just advise against going there at all, believing that the risks outweigh the benefits. That said brief intervals of exercise in that range mixed up with aerobic exercise is the basis of High Intensity Interval Training (HIIT), and there is lots of data showing its utility. Anaerobic range is not sustainable for sixty minutes. Period.

For those who use heart rate monitors the rule of thumb is to stay between 40 to 85%. The longer the aerobic exercise the lower in the range you stay. One effective approach is to develop a base around 60% of max heart rate and then add intervals nearer the 75 to 80% range of several minutes duration each, or even a few 30 second anaerobic ones.

Perceived exertion is honestly probably just as good as a monitor. You may want to test it out - rate your effort level (how hard you are breathing) and see how it correlates with what your monitor says.

Anyway, agreed with RunnerPat. Lower intensity is not better for burning fat unless you exercise longer because the lower intensity allows you to. Start off lower to build your fitness, then raise your baseline aerobic target and add in intervals of various sorts.

5

This really shows how little I know about exercising.

I did the Polar ‘fitness test’, which I assume takes my resting heart rate (the test is to wear it while fully relaxed) and combines it with age data to determine heart rate zones. I spend about ten minutes mildly ovaling along (this is on an elliptical), then about an hour huffing and puffing. I don’t know about second wind, but after ten minutes or so it goes from “wow, am I really going to do this for an hour” to “meh, I can keep this up, just don’t ask me to hold a decent conversation.”

The bulk of my time (about 45 minutes of the hour spent exerting myself) is spent in ‘Zone 3’, with the heart rate ranging a bit between 145-150. So, according to Marxxx’s info, I need to bump that up to a full sixty minutes in that zone. But according to DSeid, I need to chill a little bit and spend most of my time in the second zone.

Oh, if it makes a difference, I’m 42 and have never been fully in shape before. I’ve been watching what I eat and working with heavy objects for the past year and a half (2-3x a week) and have dropped about 40 to 50 pounds. My treadmill use has been inconsistent, but the new elliptical is much more comfortable to use. Not easier per se, but less bone-shakey so it’s easier to keep the heart rate up for the hour.

6

I also find Marxx’s mention of those studies to be a bit eyebrow raising.

85% is racing all-out for one hour.
Trying to do that every day is absolutely the path to quick injury and/or overtraining.

Rhythmdvl, your workout looks fine at that effort. For general fitness, there’s no need to ramp it up any higher.

7

“Zone 3” usually refers to 64 to 76% of max heart rate. That’s good solid aerobic range. And 145 to 150 for 42 years old is pretty good solid by most calculations. One standard approach is 220 - your age = Max heart rate. For you that is 178. By that crude measure you are pushing 80% plus. That’s working it. Others are similar to your Polar device, and use resting heart rate. By that one, if we assume your resting is 70, then it pumps out as 141 to 154 as 64-76% (Zone 3). Solid.

Your base for a 45 minute to an hour exercise should be where you can actually talk (see “the talk test”) and the fact that you would have a hard time passing that means you are probably going too hard for that duration. Yes, better down a notch with intervals of all out, or longer intervals of moderately hard to talk, peppered in. It is often more fun, and more effective, to have some days that are shorter but more intense and some less intense but longer.

Congratulations on your weight loss! And on your current plan to increase your fitness from here.