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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 10 of 10. This is the beginning of the thread.
Posted by Cass on November 28, 2004, at 16:20:34
I had my body fat measured at my gym recently. It was 27% which the trainer said was good for my height and age. I used a device that was sort of U shaped, and it had metal handles, and it had a screen on top. I think the trainer inputed my weight and height into the device. Then I held it out in front of my heart, covering the metal handles with my hands.
Does anyone know how these machines work? I'm just curious how holding this machine in front of your heart can measure body fat.
Posted by Tabitha on November 28, 2004, at 20:22:29
In reply to Measuring body fat, posted by Cass on November 28, 2004, at 16:20:34
I think it sends a low electrical current through you and measures resistance, which is supposed to correlate somehow to body fat. I'm not sure how accurate it is.
Posted by Cass on November 29, 2004, at 23:49:03
In reply to Re: Measuring body fat, posted by Tabitha on November 28, 2004, at 20:22:29
Thanks, Tabitha :)
Posted by Larry Hoover on November 30, 2004, at 9:35:23
In reply to Re: Measuring body fat, posted by Tabitha on November 28, 2004, at 20:22:29
> I think it sends a low electrical current through you and measures resistance, which is supposed to correlate somehow to body fat. I'm not sure how accurate it is.
I checked the methodology, and I think these fall into the "quack attack" category. Factors which render the reading false include such simple things as moisture level of the skin, how tightly it is gripped, and the difference in grip between the two hands. There are similar devices you stand on, and the although you don't grip them, foot position, and skin moisture content again are very significant uncontrolled variables.
The only way to calculate an accurate BMI is with mathematics. But even still, an accurately calculated BMI must be interpreted. There are athletes, like pro football players, without hardly an ounce of fat on them, who would have calculated BMIs putting them in the severely obese range.
The old-fashioned pinch-calipers which measured sub-cutaneous body fat depth are probably far more informative, from a fitness/obesity perspective.
Lar
Posted by Cass on December 1, 2004, at 10:05:03
In reply to Re: Measuring body fat, posted by Larry Hoover on November 30, 2004, at 9:35:23
Thanks for the info, Larry.
Posted by Racer on December 2, 2004, at 19:10:04
In reply to Re: Measuring body fat, posted by Larry Hoover on November 30, 2004, at 9:35:23
I had the caliper test done a few years ago. Said I was 15% body fat, which seemed so high to me, so you know what was going on with me at the time, right?
But out of all the tests that were done that day, the others seemed much more useful to me: strength, flexibility, cardiovascular conditioning, etc. But the body fat, high as I thought it was, did comfort me a little.
And I'm with you most of the way -- all those devices are pretty suspect to me. We diverge on calculating BMI, though: the most accurate measure of body mass is being weighed under water. Rarely done, but it is more accurate than mathematical calculations, by all accounts I've come across.
Otherwise, I'd go with either calipers or mathematics.
Posted by stresser on December 3, 2004, at 14:37:47
In reply to Measuring body fat, posted by Cass on November 28, 2004, at 16:20:34
You can measure body fat composition by using skin fold calipers, bioelectrical impedance, and underwater weighing. Most health clubs use the first two, although the calipers are the most accurate of the two. The bioelectrical instrument conducts electrical currents through the body in order to measure fat. Is is based on the hpothesis that tissues that are high in water content conduct electrical currents with less resistance than those with little water. Meaning, you don't want to do this one if you are de-hydrated. I personaly don't think this is accurate at all, and would tend to go with the caliper measurment if you want a true reading. Underwater weighing would probably be the most accurate. Most places don't have the factilities for it. Your body fat being 27%, isn't bad at all.....most women are trying to get their body fat DOWN to that!!-L
Posted by Cass on December 3, 2004, at 14:56:47
In reply to Re: Measuring body fat, posted by stresser on December 3, 2004, at 14:37:47
Thanks stresser. That was really informative. I was happy about the 27%, but now I'm not at all confident that it's correct. I doubt I was dehydrated, but I really don't remember how much water I had consumed that day. Maybe I should get a whole bunch of readings there to see if the results vary a lot.
Posted by stresser on December 4, 2004, at 22:56:18
In reply to Re: Measuring body fat » Larry Hoover, posted by Racer on December 2, 2004, at 19:10:04
Racer: I am wondering if you are male or female? I am assuming male afer reading your post....I am also wondering who you are refering to when you say "we"? Are you are Health and fitness professional? Thanks for the info....I hope you don't think I'm being too nosy!
Cass....don't get too stressed out about the body fat thing...remember, some of the thinnest people are actually the "fattest" people, because even though they are thin, they have a high percent body fat. The same goes with bigger framed peeople, women included! Some think they are fat, when their body fat is lower then their "skinny friends." Muscle weighs more than fat, and it looks larger as well. -L
Posted by Racer on December 9, 2004, at 16:22:36
In reply to Re: Measuring body fat, posted by stresser on December 4, 2004, at 22:56:18
> Racer: I am wondering if you are male or female? I am assuming male afer reading your post....I am also wondering who you are refering to when you say "we"? Are you are Health and fitness professional?
By "we", I meant Larry and myself. I'd say that Larry's right, for the most part, if you can't get weighed under water. But I would go for the water if I had a choice, since it does account for muscle weight somewhat more precisely than math.
And I'll bet that other question has been answered over on the Eating board, right? ;-)
> Cass....don't get too stressed out about the body fat thing...remember, some of the thinnest people are actually the "fattest" people, because even though they are thin, they have a high percent body fat. The same goes with bigger framed peeople, women included! Some think they are fat, when their body fat is lower then their "skinny friends." Muscle weighs more than fat, and it looks larger as well. -L
This is the end of the thread.
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