Someone help explain heart rate monitor calories

Zoejohnse91

Hiya!

So this might seem like an obvious question, and I feel like it is because I can't find my answer after a Google.

I burn 1950ish at BMR - so no activity just coma state, right.
Now if I was to wear my FT7 all day would the calories burnt according to that have already taken this rough figure into account and everything else is surplus OR would I have to minus my BMR from my daily burn?

With that in mind, would then any activity i do, say gym or mowing the grass, need to have my estimate 30 minutes resting burn taken away to get an accurate figure of my actual burn?

Does that make sense?

I assume my HRM already takes my BMR away during any activity and the figure I'm given is pure activity burn but I was curious. Maybe I've over thought it.

Thanks for reading!

malibu927

A heart rate monitor estimates how much you’re burning based on your heart rate. But it’s not a good judge of that for most activities. You should only wear it for steady state cardio, never all day or for mowing the grass/interval training/strength training/etc. To be safe, deducting your BMR would be a good idea, because again it’s an estimate and based on gross calories.

ExistingFish

malibu927 wrote: »

A heart rate monitor estimates how much you’re burning based on your heart rate. But it’s not a good judge of that for most activities. You should only wear it for steady state cardio, never all day or for mowing the grass/interval training/strength training/etc. To be safe, deducting your BMR would be a good idea, because again it’s an estimate and based on gross calories.

I used (it broke) a chest heart rate monitor specifically for interval training. Keeps track of heart rate while in intervals. It gave me a reasonable estimate of calories burned for the work output.

But it was crap for the weight training. Good for aerobic exercise (both interval and steady state, if you use an accurate one like a chest strap), not anaerobic exercise (like lifting weights).

NorthCascades

Some devices do, others don't. There isn't one correct way of doing it, there are a bunch of different ways of guessing. Remember there isn't some specific number of heart beats in a calorie, HRMs don't have any special insight into what's going on inside your body, other than being able to tell you your pulse rate.

AnvilHead

Good write-up about HRMs here, with a pretty thorough explanation of what they do and don't do:
https://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

AnnPT77

Welllll . . . I think there's no magic in a HRM, and it can seriously mislead. (I say this as someone who uses one regularly, BTW.)

Heart rate is a proxy for work effort, not a measurement of it. Heart rate increases when it's hotter weather, when we're dehydrated, when we're excited, when we're straining, and a bunch of other stuff that burns no extra calories.

Those factors make a HRM a pretty bad estimator of strength training calories, for most people: Lots of strain, which raises heart rate, less actual work that burns calories = poor estimate.

I disagree that it's theoretically accurate for interval cardio . . . it can be relatively more or less accurate for any exercise depending on fitness level, which is especially true for intervals. The problem is that what mostly determines calorie burn is the actual work done: A 150-pound person running a mile will burn roughly the same number of calories, fit or unfit. The fit person may run it faster; if they slow down and run it at the same speed, their heart rate will be lower, so the HRM may say they burned fewer calories when they didn't. If the two people do that mile in run/walk intervals, the fit person's heart rate will drop quickly during the walk intervals, while the less fit person's heart rate will stay high through a good bit of the walk portion, and make it look like they're still working hard when they're not. It's problematic.

Also, all HRM are not created equal.

Different models use different inputs and different algorithms to estimate calories. A GPS-enabled HRM would have an input of how far those two people above actual ran, and maybe even how hilly it was; if the HRM's algorithms use that data, it could theoretically produce a more accurate estimate. Does it that use that data? Hard to find out. Does it use the data in well-researched, sensible ways? Even harder to find out.

At the most basic level, a HRM that doesn't know your personal measured (not age-estimated) HRmax is less likely to be accurate, because the age-based HRmax formulas are pretty commonly inaccurate. Without an accurate HRmax, the HRM can't produce an accurate calorie estimate, unless you coincidentally fit the age-based estimates of HRmax. Similarly, if the HRM doesn't know, measure or estimate your true resting HR, it doesn't have a good basis for understanding how hard you're working. Similar issue for your VO2max.

Bottom line: It's all estimates.

Here's the thing: It may not really matter how you estimate your exercise calories, within reason.

Whaaaa?!?!

If you track your intake, and you're consistent (not necessarily accurate) in how your log your exercise, and your exercise itself is at least somewhat consistent . . . then your weight loss results tell the story. Losing too fast, or losing when you shouldn't lose? Increase calories eaten. Losing too slowly, or gaining when you should hold steady? Decrease calories eaten. For most people, consistency in estimating is good enough to make that work.

There can be an exception for people who are eating so little that they get weak and fatigued, so are listless in daily life and exercise: They can lose more slowly than expected, because they've reduced their calorie expenditure but haven't recognized that (it can be subtle). Eating a little more may help their energy level enough to improve their daily-life calorie expenditure and their workout intensity, and perk up their weight loss rate.

This is not saying that if you eat too little your body goes into "starvation mode" and holds onto fat. If that were a thing, no one would ever starve to death, and (sadly) many people worldwide starve to death every day, and they aren't fat when then do so. That "holds onto fat" idea is a myth.

This is good reading about HRM: https://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

For your HRM specifically, you'd need to read up (or ask the manufacturer) whether it's giving you net calorie burn (excludes BMR) or gross (includes BMR). There's some variation, and in some cases it depends on how you ask (what's in the display vs. what it sends MFP during data exchange). Many/most sources give gross burns (includes BMR).

sijomial

You can't use a basic HRM like the FT7 as an all day activity monitor - it's for use during exercise only. And only likely to be vaguely reasonable for a limited subset of exercise - the closer to steady state and at least moderate cardio the better. The further away the more pointless it is to use for anything except counting heartbeats.
Don't use it for gardening or strength training!

There is no direct relationship between heart rate and calories - my calorie needs haven't dropped by 20% because my resting heart rate has dropped from 60 to 48bpm, my heart is just pumping better. Your HRM is using heart rate as a proxy for oxygen uptake for a general population. Where you sit in that general population average is anybody's guess.

It might give vaguely reasonable estimates for cardio exercise but with a huge range of personal inaccuracy. You could try calibrating yourself against a more reliable method such as a power meter for cycling, a Concept2 rower or a running formula - that would at least give you an idea.
My FT7 over-estimated by c. 20-30% for steady state cardio. Part of that is because I believe it's trying to estimate gross calories.

Zoejohnse91

Thanks for the insight everyone! I hate estimating things but it seems to be a big part of weight loss and body stuff.

TavistockToad

Zoejohnse91 wrote: »

Thanks for the insight everyone! I hate estimating things but it seems to be a big part of weight loss and body stuff.

but all of your CICO numbers are estimates with varying degrees of accuracy...

Zoejohnse91

TavistockToad wrote: »

Zoejohnse91 wrote: »

Thanks for the insight everyone! I hate estimating things but it seems to be a big part of weight loss and body stuff.

but all of your CICO numbers are estimates with varying degrees of accuracy...

Oh I know that I'm just apparently looking for a more accurate approach when it seems (now I've been told) there is none.

AnvilHead

Zoejohnse91 wrote: »

TavistockToad wrote: »

Zoejohnse91 wrote: »

Thanks for the insight everyone! I hate estimating things but it seems to be a big part of weight loss and body stuff.

but all of your CICO numbers are estimates with varying degrees of accuracy...

Oh I know that I'm just apparently looking for a more accurate approach when it seems (now I've been told) there is none.

None that are practical for everyday use. It would either involve living in a metabolic chamber or doing all your exercise while hooked up to EKG and oximeter in a lab, with trained scientists to record and interpret the results.

Short of that, about the closest you can come is training on a bicycle equipped with a power meter.

Unknown

This content has been removed.

AnvilHead

Frazdogg wrote: »

AnvilHead wrote: »

Zoejohnse91 wrote: »

TavistockToad wrote: »

Zoejohnse91 wrote: »

Thanks for the insight everyone! I hate estimating things but it seems to be a big part of weight loss and body stuff.

but all of your CICO numbers are estimates with varying degrees of accuracy...

Oh I know that I'm just apparently looking for a more accurate approach when it seems (now I've been told) there is none.

None that are practical for everyday use. It would either involve living in a metabolic chamber or doing all your exercise while hooked up to EKG and oximeter in a lab, with trained scientists to record and interpret the results.

Short of that, about the closest you can come is training on a bicycle equipped with a power meter.

Or, you can log your calories, and over time, watch the results, and adjust, as necessary. It’s the same thing as being accurate. It just takes some time.

And is a LOT less expensive and inconvenient.

Zoejohnse91

Thanks everyone 😁

NorthCascades

sijomial wrote: »

You can't use a basic HRM like the FT7 as an all day activity monitor - it's for use during exercise only.

Years ago I wore a chest strap to bed over night, to learn what my resting heart rate was. When I got up in the morning, the watch it was connected to thought I burned thousands of calories from whatever exercise I was doing. They're each programmed differently, this one assumed that if I was using it, that meant I was doing some kind of exercise.

NorthCascades

Zoejohnse91 wrote: »

TavistockToad wrote: »

Zoejohnse91 wrote: »

Thanks for the insight everyone! I hate estimating things but it seems to be a big part of weight loss and body stuff.

but all of your CICO numbers are estimates with varying degrees of accuracy...

Oh I know that I'm just apparently looking for a more accurate approach when it seems (now I've been told) there is none.

Well, it's not so much that. If you go for a walk, you burned 1/3 your body weight in pounds. If you go for a run, you burned 2/3 your weight in pounds. Both in calories. If you ride a bike, a power meter will get you within 2.5 % of the truth for calories. But when it comes to mowing the grass or Zumba or basically the rest of life, things get fuzzier.