Succorso said:Couldn't find anything when googling this group, but I'm sure this
must have been asked here before.
I had a very enjoyable 100+km ride today in the "spring" sunshine
(what happened to winter? I must have blinked and missed it) wearing
my HRM as usual.
It claimed I used 4600 calories. This seems excessive to me. I was
riding for about 4 hours all told, at about 75% of my Max HR (avr
140). I would describe my cycling as "moderate" - not a tough workout
by any means. Most websites I've been to about calorie consumption
would put a rate of about 500 calories an hour for "moderate" cycling.
Ergo, I would have expected to use about 2000 calories. Are HRM's just
that approximate?
Well.. two things here.
a) The HRM. Unless you can get a trace from it, or at a minimum some
estimates of max and average HR for the time period its pretty hard to tell
if the HRM was measuring heart-rate accurately.
Most are pretty accurate if the chest strap has a good electrical contact
with the skin and the watch is in range of the strap.
However, even ignoring rogue signals from a badly fitting chest strap, there
are things which can interfere with some models, including another HRM in
the vacinity, a wireless bike computer, a mobile phone, car electronics
(usually inside the car, not outside), etc. More modern designs are less
susceptible to interference, particularly from adjacent HRMs.
b) The Calorie conversion. This is approximate regardless of the HRM
heart-rate accuracy. It needs some calibration based on a person's weight
and resting heart rates, but even then, its no more than a rough guide.
- Nigel
--
NC - Webmaster for http://www.2mm.org.uk/
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