Heart Rate Monitor

Status
Not open for further replies.
K

Kees Van Malsse

Guest
BentJay wrote:
>
> Keith,
>
> You seem to be very knowledgeable so I hope you don't mind if I ask you some questions. I use a
> Cateye computer w/heartrate (when I wear the chest strap.) It has a calorie readout. Since there's
> no way to input my weight, it generates calories based on time and heartrate. Might there be a
> formula to roughly convert the readout into an approximate calorie count. For example, if the
> Cateye is calibrated to a 150 lb person isn't there a ratio for a 300 pounder? I've read that
> Polar htm have batteries that must be replaced only by the factory. Is this true?
>
> BentJay

Although not Keith, I might answer your question a bit. Once upon a time, when I started with my
Cateye HB100 (my second HRM, the first was of the earclip type, then the only affordable one) I
approached Cateye with the question how the calories where measured/calculated. The answer was clear
and frank: it is just an indication based on a pile of assumptions. What it does is assume a certain
nr of calories burned with every heartbeat above 90. Test this by using your HRM for 10 minutes will
staying relaxed. The readout shows zero Calories burned. It is obvious that when becoming better
trained and your heart rate goes down for similar excersize, the calculated Calories go down, whilst
the actual calories don't!

I had the pleasure last year riding for a month with the SRM system. A special chainset that
measures (within 2%) the actual power you put into your cycling. It also measured speed, cadense,
distance and heart rate. By using my HB100 aside the SRM system, I could "calibrate" the HB100
Calorie calculations. You make a reasonable estimate when presuming an energy efficiency of 25%
for your body. So every kJ work delivered consumes about one kcalorie (or Calorie, mind the
Capital C) (1 cal = 4.18 J). To my surprise, the HB100 was reasonably close -for the fitness of
that moment, that is.

The calorie calculations are mostly a bit of fun. But they do work as a rough estimate of what
you burned.

Cheers, Kees

K

Keith

Guest
[email protected] (BentJay) wrote ...

> I use a Cateye computer w/heartrate (when I wear the chest strap.) It has a calorie readout. Since
> there's no way to input my weight, it generates calories based on time and heartrate. Might there
> be a formula to roughly convert the readout into an approximate calorie count. For example, if the
> Cateye is calibrated to a 150 lb person isn't there a ratio for a 300 pounder?

Sorry to disappoint you, but the science behind the calorie use is very shakey. We all love numbers
and precision and are suckers for an objective means of measuring progress, but there is no way a
simple heart rate monitor will be able to do this for you. Just because the HRM provides numbers
easily, doesnst mean they translate into useful information. Sports scientists measure the air you
exhale, your blood every few minutes and do urinalysis and well as heart rate and a whole lot of
physiological parameters as well over a number of months in order to come close to the answer. The
HRM manufacturers and retailers will tell you otherwise - of course

Incidentally, here's a link to the origins of the '220 minus your age' myth:

http://www.athletictrainingservices.com/MHR.htm

> I've read that Polar hrm have batteries that must be replaced only by the factory. Is this true?

Not true. I have had the batteries replaced in a Polar HRM by my local watch repairer. It was
waterproof afterwards. HOWEVER, I wouldn't do it again. It's my guess Polar make very little money
out of this service and they always replace the waterproof seal with a new factory-supplied one when
they replace the battery. My experiance with Polar has been consistently favourable. Save a few
dollars by going elsewhere, but don't attribute any subsequent problems to the Polar product.

Keith

R

Rob Rudeski

Guest
Do ALL Polar HRMs require factory servicing for battery changes? Are there any models that are user
serviceable? What is the turnaround time when you do send it back? Can you send them back to Polar
on your own, or do you have to go through a bike shop service department?

My dive computers (both ScubaPro/Uwatec) require factory service to change batteries, and since I
have to go through my dive shop, often takes a couple weeks and costs quite a few bucks. I save a
little by having this done in conjunction with my annual servicing of the rest of my gear.

--
Rob Rudeski Trenton, GA RANS V2 "Keith" <[email protected]> wrote in message
news:[email protected]...
> [email protected] (BentJay) wrote ...
>
> > I use a Cateye computer w/heartrate (when I wear the chest strap.) It has a calorie readout.
> > Since there's no way to input my weight, it generates calories based on time and heartrate.
> > Might there be a formula to roughly convert the readout into an approximate calorie count. For
> > example, if the Cateye is calibrated to a 150 lb person isn't there a ratio for a 300 pounder?
>
> Sorry to disappoint you, but the science behind the calorie use is very shakey. We all love
> numbers and precision and are suckers for an objective means of measuring progress, but there is
> no way a simple heart rate monitor will be able to do this for you. Just because the HRM provides
> numbers easily, doesnst mean they translate into useful information. Sports scientists measure the
> air you exhale, your blood every few minutes and do urinalysis and well as heart rate and a whole
> lot of physiological parameters as well over a number of months in order to come close to the
> answer. The HRM manufacturers and retailers will tell you otherwise - of course
>
> Incidentally, here's a link to the origins of the '220 minus your age' myth:
>
> http://www.athletictrainingservices.com/MHR.htm
>
> > I've read that Polar hrm have batteries that must be replaced only by the factory. Is this true?
>
> Not true. I have had the batteries replaced in a Polar HRM by my local watch repairer. It was
> waterproof afterwards. HOWEVER, I wouldn't do it again. It's my guess Polar make very little money
> out of this service and they always replace the waterproof seal with a new factory-supplied one
> when they replace the battery. My experiance with Polar has been consistently favourable. Save a
> few dollars by going elsewhere, but don't attribute any subsequent problems to the Polar product.
>
> Keith

C

Cletus D . Lee

Guest
In article <[email protected]>, [email protected] says...
> Do ALL Polar HRMs require factory servicing for battery changes? Are there any models that are
> user serviceable? What is the turnaround time when you do send it back? Can you send them back to
> Polar on your own, or do you have to go through a bike shop service department?
>
> My dive computers (both ScubaPro/Uwatec) require factory service to change batteries, and since I
> have to go through my dive shop, often takes a couple weeks and costs quite a few bucks. I save a
> little by having this done in conjunction with my annual servicing of the rest of my gear.
>
>
AFAIK al Polar HRMs require factory service for a battery change. FWIW, My Sports Instruments ECG5
battery (CR2032) can be replaced by the user. It is also less sensitive to electrical interference.
--
Cletus D. Lee Bacchetta Giro Lightning Voyager http://www.clee.org
- Bellaire, TX USA -

R

Rick Moll

Guest
Rob Rudeski wrote:
> Do ALL Polar HRMs require factory servicing for battery changes? Are there any models that are
> user serviceable? What is the turnaround time when you do send it back? Can you send them back to
> Polar on your own, or do you have to go through a bike shop service department?

The Polar HRM receivers don't actually *require* factory service for battery replacement. I've done
it myself. On the units I have, the back cover comes off with four small screws, and the battery is
a commonly available type. The seal is an O-ring, that I simply reused.

However, Polar recommends that you send the HRM receiver back to them for battery replacement. You
send the unit directly to them. The cost is \$12.95 including their shipping and handling charge.
I've never done it, so I can't comment on the turn around time.

http://www.polarusa.com/service_repair/show_faq_con.asp?ID=4

Rick Moll

Status
Not open for further replies.