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02-01-2007, 11:24 AM

In article <1170349029.605054.235430@m58g2000cwm.googlegroups .com>,
Prisoner at War <prisoner_at_war@yahoo.com> wrote:
>
>For immediate release from Ye Olde Rambling Question Dep't.:
>
>I'm on some elliptical at the gym, have been doing it 40 minutes three
>times a week, each session the machine read-out claims I've lost
>~850-900 calories (range due to variable intensity)...how accurate is
>that? I find it hard that with 40 minutes of sweat I've burned that
>many calories. It doesn't feel too hard, relatively speaking (though
>I do Level 15 out of 20 available, with 20 as the hardest).

Not very accurate there. But not to worry. It'll be accurate in a
relative sense. If you go and do what it says was 1500 calories, you
probably burned off twice as many as if it said 750. How many that
was ... don't really know.

>There's also the heart rate monitor that has me at the upper celing of
>my target heart range (which is supposed to be ~142-157 for a 35 y.o.)
>for almost all 40 minutes, which I find incredible, too...I definitely
>look like I'm fit -- Greco-Roman statue and all -- but it all feels
>much easier than I'd expected (though there is surely a psychological
>component involved, and I've learned fairly well to tune out
>unpleasantries like fatigue, etc.), so I'm wondering whether such
>devices are trustworthy...how are such numbers calculated, anyway? On
>this elliptical, the target heart rate seems to come from sensors in
>the handles....

See my page on heart rate training (though oriented to runners, the
effort levels carry across aerobic activities fairly well)
http://www.radix.net/~bobg/run/hr.html

The target range was computed based on your age, and some assumptions
of where you want to be exercising. But all estimators have a 10+ beat
per minute standard error. Consequently, my observed maximum heart rate
is a good 15 beats per minute higher than the 220-age estimator would
suggest.

Further, if the targeting from the machine didn't ask about your resting
heart rate, you can, again, be comfortable far above the level a simpler
estimate would say. Again, see my page for a little calculator and
verbal descriptions of effort levels. Heart rate reserve seems to work
much better for people.

(No, no advertising or the like. Just that I wrote a fair amount into
the page, and don't want to retype it all.)

--
Robert Grumbine http://www.radix.net/~bobg/ Science faqs and amateur activities notes and links.
Sagredo (Galileo Galilei) "You present these recondite matters with too much
evidence and ease; this great facility makes them less appreciated than they
would be had they been presented in a more abstruse manner." Two New Sciences

02-01-2007, 11:24 AM	#6 (permalink)
Robert Grumbine Guest Posts: n/a	Re: How Accurate Are Those Monitors, Anyway? In article <1170349029.605054.235430@m58g2000cwm.googlegroups .com>, Prisoner at War <prisoner_at_war@yahoo.com> wrote: > >For immediate release from Ye Olde Rambling Question Dep't.: > >I'm on some elliptical at the gym, have been doing it 40 minutes three >times a week, each session the machine read-out claims I've lost >~850-900 calories (range due to variable intensity)...how accurate is >that? I find it hard that with 40 minutes of sweat I've burned that >many calories. It doesn't feel too hard, relatively speaking (though >I do Level 15 out of 20 available, with 20 as the hardest). Not very accurate there. But not to worry. It'll be accurate in a relative sense. If you go and do what it says was 1500 calories, you probably burned off twice as many as if it said 750. How many that was ... don't really know. >There's also the heart rate monitor that has me at the upper celing of >my target heart range (which is supposed to be ~142-157 for a 35 y.o.) >for almost all 40 minutes, which I find incredible, too...I definitely >look like I'm fit -- Greco-Roman statue and all -- but it all feels >much easier than I'd expected (though there is surely a psychological >component involved, and I've learned fairly well to tune out >unpleasantries like fatigue, etc.), so I'm wondering whether such >devices are trustworthy...how are such numbers calculated, anyway? On >this elliptical, the target heart rate seems to come from sensors in >the handles.... See my page on heart rate training (though oriented to runners, the effort levels carry across aerobic activities fairly well) http://www.radix.net/~bobg/run/hr.html The target range was computed based on your age, and some assumptions of where you want to be exercising. But all estimators have a 10+ beat per minute standard error. Consequently, my observed maximum heart rate is a good 15 beats per minute higher than the 220-age estimator would suggest. Further, if the targeting from the machine didn't ask about your resting heart rate, you can, again, be comfortable far above the level a simpler estimate would say. Again, see my page for a little calculator and verbal descriptions of effort levels. Heart rate reserve seems to work much better for people. (No, no advertising or the like. Just that I wrote a fair amount into the page, and don't want to retype it all.) -- Robert Grumbine http://www.radix.net/~bobg/ Science faqs and amateur activities notes and links. Sagredo (Galileo Galilei) "You present these recondite matters with too much evidence and ease; this great facility makes them less appreciated than they would be had they been presented in a more abstruse manner." Two New Sciences