HRMs and strength training

Azdak

HRM's don't work at all for weight training. They're not made for that. The calculations are based on higher oxygen levels in the blood that only occur with cardio exercise.
Using a heart rate monitor when weight lifting would be the same as using it to calculate how many calories you burned when something scared you. Your heart rate increases but it's not the same as cardio.

I do circuit training with weights which gets my heart rate up, would it work for that?

Depends on the mix of exercises and the intensity of the lifting (i.e. the % of 1 RM max). Usually, circuit training routines will lead to an HRM OVERestimating calorie burn. That's because heart rate increases out of proportion to oxygen uptake. Oxygen uptake is the determining factor for how many calories you burn. During steady-state aerobic exercise (the type of exercise HRMs are programmed to measure), heart rate and oxygen uptake have a relatively fixed relationship. Therefore, it can be assumed that changes in heart rate reflect changes in oxygen uptake.

During circuit training, that relationship can become distorted, esp with upper-body strength movements. It can result in the HRM overestimating calorie burn by 25%-45%. (That's with a circuit that combines cardio and strength movements).

The general rule of thumb is that the higher the resistive component of the movement, the less reliable heart rate is as a marker for increased oxygen uptake and the more likely the HRM will overestimate calories.

Azdak

HRMs will work for weight training regimens based on compound lifts. They will not work for isolation lifts and will give you an incorrectly high reading.

Nope, not for those either. The underlying physiology is different than the assumptions upon which HRM calorie-estimating algorithms are based.

MoreBean13

Bump.

Azdak

Here's a excerpt of an article written by a certified trainer. It explains some of the technical aspects of HRM not working for weight training...



The problem is a technical one. Calorie burning isn't determined by heart rate, it's determined by the number of muscle cells that are activated to perform a given activity. It's the working cells that actually use the energy (calories) and consume oxygen. When working muscle cells need more energy and oxygen, your heart rate goes up to deliver these things to the cells via the blood stream.

Any muscle that performs a high intensity or maximum effort (strength training) will trigger an increase in heart rate and blood flow. But if only a single muscle group is on the receiving end to utilize that extra oxygen (doing a strength exercise that isolates your biceps, for example), only a relatively small amount of oxygen (and calories) will actually be consumed.

So while a series of strength training exercises may elevate your heart rate like aerobic exercise does, you're not actually using as much oxygen and burning as many calories as you would be if you were steadily using several large muscles all at once, as when walking, running, swimming, or doing aerobics for example.

The heart rate monitor doesn’t know whether your increase in heart rate is due to several large muscle groups working (cardio), an isolated muscle group lifting a weight (strength training), or even if adrenaline or excitement is increasing your heart rate. It just knows your heart rate, and the formulas it uses to estimate calories are based on studies of aerobic exercise, not other activities. So, it's going to overestimate your calorie expenditure when the rise in heart rate is stimulated by using isolated muscles at maximum intensity, which is what occurs during strength training.

FWIW, while this explanation is not exactly wrong, it's not correct either. It's true that overall oxygen uptake (VO2) is less during strength training and that might be due to the smaller muscle mass being used (although, quite frankly I have never heard it explained that way or read it in any exercise physiology textbook). He is also correct in stating that HRM calorie formulas are based on studies of aerobic exercise.

However, the increased heart rate that occurs with heavy lifting is due to the increased intrathoracic pressure and increased peripheral resistance, which leads to an increased afterload and decreased cardiac output. It has nothing to do with the smaller muscle mass being utilized. Because of that, there is a complete dissociation of the relationship between heart rate and VO2. That's why HRMs calorie counts are useless.

Azdak

A couple of things:

I have the polar FT7. I've never noticed any interference between my watch and chest strap, but I have had interference between my chest strap and the machine I'm using that was caused by my iPhone. It was giving me a heart rate of over 200 bpm when I first got on the machine.

Also, I believe a HRM does work well enough for circuit training, assuming you have very limited rest between exercises. I presume you do 4-6 different exercises back-to-back and then rest for 30-60 seconds? Just stop the HRM during the rest period and then start it for the next set.

Like others have said, the more fit you get, the higher your VO2MAX becomes, which means your heart does not need to beat as fast to supply your body with the oxygen it needs. Because of this, your reported caloric burn will go down the more fit you get. There are some HRM's out there that either allow you to enter your VO2MAX, or provide a utility that tries to guess your fitness level based on your resting heart rate. These HRM's obviously are more expensive, but provide a higher degree of accuracy. As others have stated, no matter how much money you spend for a top-of-the-line HRM, you're still only getting a guess at caloric burn.

Just wanted to point out (and you probably meant this so I apologize if I am stepping on your comment) that, although the "reported" caloric burn on the HRM goes down as you become more fit, your ACTUAL caloric burn does not (unless you have lost weight).

Increased fitness doesn't mean you burn fewer calories at the same workload--it means you can work HARDER (i.e. at a higher workload) and burn MORE calories at the same heart rate (because your max has increased).

Any HRM that doesn't allow you to change VO2max as your fitness increases, or doesn't account for increases in fitness level, will become more inaccurate over time.

Azdak

They sure do! Even the number on the machines at the gym seems suspicious to me. I used to use the elliptical all the time...I feel like I could do the laziest workout ever, and not even break a sweat, and the elliptical would say I burned 300 cals in 30 mins. There is just no way. I don't even burn that running.

I should add that I'm only 5'2 and only slightly overweight, so I don't put up huge calorie burns in the first place.

Machines lie, it's their job. You'll be surprised if you run on the treadmill with a HRM how different the calorie burn is compared to what the machine says. If you eat exercise calories it can make a huge difference.

If you are walking on a treadmill, entered your weight on the treadmill, and are not holding on to the handrails, and the calorie reading on your HRM is way off, it's your HRM that is wrong, not the treadmill.

It's not the "job" of machines to "lie" --at least not all of them, and not recently. For some machines--e.g. treadmills--the equations used to estimate calories are relatively simple and well-validated. They overestimate somewhat for running, but no more than HRMs do all the time.

For others, (e.g. ellipticals) the calorie inaccuracy is not due to any secret conspiracy, but the cost and the methodological challenges of developing machine-specific algorithms.

faceoff4

Has anyone experienced erratic readings caused by TVs at the gym, cell phones near you, other HRMs near you, etc?

This does happen with lower end HRM's, but just get the model that blocks out any interference with other machines, hrm's, etc and you shouldn't have any issues

SteveHunt113

A couple of things:

I have the polar FT7. I've never noticed any interference between my watch and chest strap, but I have had interference between my chest strap and the machine I'm using that was caused by my iPhone. It was giving me a heart rate of over 200 bpm when I first got on the machine.

Also, I believe a HRM does work well enough for circuit training, assuming you have very limited rest between exercises. I presume you do 4-6 different exercises back-to-back and then rest for 30-60 seconds? Just stop the HRM during the rest period and then start it for the next set.

Like others have said, the more fit you get, the higher your VO2MAX becomes, which means your heart does not need to beat as fast to supply your body with the oxygen it needs. Because of this, your reported caloric burn will go down the more fit you get. There are some HRM's out there that either allow you to enter your VO2MAX, or provide a utility that tries to guess your fitness level based on your resting heart rate. These HRM's obviously are more expensive, but provide a higher degree of accuracy. As others have stated, no matter how much money you spend for a top-of-the-line HRM, you're still only getting a guess at caloric burn.

Just wanted to point out (and you probably meant this so I apologize if I am stepping on your comment) that, although the "reported" caloric burn on the HRM goes down as you become more fit, your ACTUAL caloric burn does not (unless you have lost weight).

Increased fitness doesn't mean you burn fewer calories at the same workload--it means you can work HARDER (i.e. at a higher workload) and burn MORE calories at the same heart rate (because your max has increased).

Any HRM that doesn't allow you to change VO2max as your fitness increases, or doesn't account for increases in fitness level, will become more inaccurate over time.

Thank you for the clarification. I didn't state this, but it is very true.

It became clear to me that I was getting into better shape when I had to increase the resistance level on the elliptical to get the same HR I had been getting months earlier. This made me realize that I had to work even harder to get the same readings, meaning I was burning more in reality to get the same caloric burn I had been getting at a lower intensity.

That's why I like the HRM's that use VO2MAX ... now to find a way of getting an accurate VO2MAX reading...

heybales

That's why I like the HRM's that use VO2MAX ... now to find a way of getting an accurate VO2MAX reading...

Interesting study results. Formula based on some stats and answers is better than sub-maximal test, and almost as good as full-blown test. Unless very high VO2max.

http://www.myfitnesspal.com/topics/show/577839-hrm-s-with-vo2max-stat-improve-calorie-estimate

But, an even more recent study formula with slightly better accuracy is found on the HRM tab here in the VO2max section, where it does the math for you. This is the one that Polar uses and tweaks slightly on their Fitness Test, according to their website regarding their test.

https://docs.google.com/spreadsheet/ccc?key=0Amt7QBR9-c6MdGVTbGswLUUzUHNVVUlNSW9wZWloeUE

aweigh2go

I've skimmed through many of the replies and they all seem great but not really clear how I would measure my calories burned via strength training. I have a Polar HRM but I have come to realize that I don't burn 1,000 calories during a leg workout! I am aiming to lose 2 lbs per week. I think my TDEE is around 2,400 and I know I won't survive on 1,400 calories a day so I am looking to create a deficit of 500 cal/day with diet and burn 500 calories per day via strength training or a strength training/cardio program. How accurate is MFP and if not very accurate, should I use a percentage of the calories calculated?

Jynus

I've skimmed through many of the replies and they all seem great but not really clear how I would measure my calories burned via strength training. I have a Polar HRM but I have come to realize that I don't burn 1,000 calories during a leg workout! I am aiming to lose 2 lbs per week. I think my TDEE is around 2,400 and I know I won't survive on 1,400 calories a day so I am looking to create a deficit of 500 cal/day with diet and burn 500 calories per day via strength training or a strength training/cardio program. How accurate is MFP and if not very accurate, should I use a percentage of the calories calculated?

Again, it's not clear because there is no way to do it. When you're doing cardio, your body is using the cardio energy system. the cardio energy system uses oxygen from the air you breath + ATP to power the muscles. Your heart provides that oxygen. Thus you can use a formula to guestimate how much oxygen is being used per heart beat, and thus how many calories the body is using to meet it's energy demands.

When you're doing strength training, you are NOT using oxygen. You're using stored energy inside the muscles. so there is ZERO way to correlate what a HRM says with what your body is actually doing.

There are general rules though. The heavier you lift, and the more compound movements you do, the more calories you burn. In addition, the 'afterburn' from weight training is significant. Weight training by design is meant to break down muscle tissue. The rebuilding of this tissue comes from calories. Ask people at a high intermediate strength level doing template like say Westside for skinny *kitten* 3 who are trying to gain weight. For the 4-5 hours of exercise they do a week, they need to pound back an absurd level of calories. Myself was able to lose weight on 3k a day, I was topping out at 5k a day trying to gain. But the point here is if you're actually doing weight training properly. As in actually pushing yourself to the limits, where you actually are breaking down muscle tissue. If we're talking circuit training, or those weight training programs where people just do light weights and don't really go to failure ever, then you're missing out on a huge level of afterburn.

TLDR: HRM's suck for resistance training. Resistance training can burn a crapton of calories if you lift heavy, and push yourself.

3dogsrunning

Bump For the awesome explanation above.

kristy6ward

Look into the Polar FT60 for its built in training program and fitness test.. and ability to add features like a foot pod for outdoor running. And also the Polar FT80 which has the same features but was specifically designed to track strength training.

3dogsrunning

Look into the Polar FT60 for its built in training program and fitness test.. and ability to add features like a foot pod for outdoor running. And also the Polar FT80 which has the same features but was specifically designed to track strength training.

Yes, to "optimize" your strength training by tracking heartrate and letting you know when to do your next set, not estimate calories.

KeithAngilly

HRM's don't work at all for weight training. They're not made for that. The calculations are based on higher oxygen levels in the blood that only occur with cardio exercise.
Using a heart rate monitor when weight lifting would be the same as using it to calculate how many calories you burned when something scared you. Your heart rate increases but it's not the same as cardio.

The benefits of weight training come after instead of during.
The more muscle you have on your body the more calories your body burns thru the day.

I love this post and, imho, this is why it is important to do some resistance training. NOTHING burns fat like recovering muscle tissue. Having said that, I imagine you could just flip on the hrm and get a rough calorie count for the time spent doing some cross-training and resistance training in the . That's my intention, anyway. We will see how it goes...

mwestonp

I use a Suunto M4 and think it's great. My wife has the Polar FT4 and loves it...she says it's easy to use and the strap is comfortable. The chest strap is the only way to go in my opinion. I have never had my watch pick up interference, but I have had the machine I was using (treadmill) pick up a chest strap signal from an adjacent runner.

As far as using the HRM for weight lifting, I don't recommend it. From my experience it over-calculates your calories burned. Based on my experience I'd suggest either not counting the weight lifting calories or just use the standard MFP calculation for it as it seems relatively close.

Best of luck to you!

MIM49

If you want more reading on the subject click on the word "Search" in the bar above the posts, type in HRM and you will get 50 pages of responses.