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
>
> 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