heart rate monitor question

sheldonklein

I understand that strapless monitors are less accurate. But they are also cheaper and more convenient. So how inaccurate are they? If I want to use a HRM to measure exercise calories and assess whether I'm exercising at a reasonable intensity, how far off will I be?

bwogilvie

There are really two separate issues here:

(1) Do strapless monitors provide an accurate heart rate reading? It seems as if the latest ones that use LEDs and sensors to read pulse from the blood vessels under the skin, like the Mio Alpha, work pretty well, but I'm not sure those are any cheaper.

(2) Does the HRM (with or without a strap) provide an accurate estimate of calories burned? The jury is still out on that. Many HRMs use an equation that's derived from this study. But unless the HRM asks for your VO2max (maximum oxygen uptake, which needs to be tested), the results aren't necessarily going to be that accurate. If two people of the same age, height, weight, and gender are exercising with the same heart rate, most HRMs will say that they are burning the same number of calories. An unfit person, though, will burn fewer than a fit person, because the fit person's heart is pumping more blood with each heartbeat.

HRMs are better than MFP's database for estimating calorie burns; you could try out a cheap one and see how its estimates match your actual weight loss results.

For determining exercise intensity, though, it's a lot cheaper and just as reliable to use the talk test:

Can you sing? You're exercising at low intensity.
Can you talk comfortably but not sing? You're exercising at moderate intensity.
Can you talk but it's getting uncomfortable? You're around your lactate threshold.
Is talking hard? You're above your lactate threshold and exercising at high intensity.

brianpperkins

Most non-strap HRMs do not provide continuous readings which makes them inherently inaccurate. There are the exceptions such as the Mio and TomTom Cardio series (among others) that use continuous optical readings, but they are as costly as the chest strap versions. The cheaper, non-strap HRM's require touching the watch for it to take a snapshot of your pulse. They collect a data point at each touch while continuous read monitors provide a more complete picture.

Coupling an incomplete picture of your cardiac activity with the formulae that have their own sets of issues (as previously mentioned) compounds the errors.

SweatLikeDog

Heart rate monitors are great for measuring heart rate, but not so great for calculating calorie burn. Intensity is usually gauged as a percentage of your max heart rate for a particular exercise. You can estimate max heart rate using age-based formulas which are rather useless (does everyone of the same age really have the same max heart rate???) or you can measure your max heart rate going all out for each exercise you do.

MikeInAZ

I don't think the strapless ones are cheaper. There are a couple of wrist tracking devices out there (Basis, Amiigo, possibly a new Fitbit). Those are all over $200. Also there have been some problems when your wrist moves around a lot (like in a push up or burpee). The LED technology is still new here.

I use a Polar H7 ($45 on Amazon http://bit.ly/polarh7). It works great, it syncs with the Polar treadmills at the gym, other Polar devices (H4/H7, Loop), and many apps.

I use it with the Digifit app (http://www.digifit.com) which costs all of $5 and it gives me really good, detailed data.

I don't mind wearing the chest strap at all, it stays secure, I don't notice its on me. And the battery lasts 6 months or more!

jacksonpt

It's impossible to say. They are just estimates that are the result of formulas and calculations. They'll be very accurate for some people, and they'll be light years off for others. "Accuracy" can also depend on the activity.

The whole notion of accurate calorie counting is a fallacy.

sheldonklein

Thanks for all the responses. They've persuaded me not to buy one.