Hydrostatic Body Fat Test

  • gwuinsf

    Posts: 525

    Aug 23, 2007 6:00 PM GMT
    I just did this for the first time yesterday. I've always wanted to do it. My results were surprising and depressing. The good thing is I now know how many pounds of body fat I'd like to drop. I'd like to get more cut, not necessarily any more muscular.

    This is the most accurate way to test one's total body fat, correct?
  • swimbikerun

    Posts: 2835

    Aug 23, 2007 8:15 PM GMT
    Yeah it is the most accurate method.
    The BMI index is also fairly accurate.
  • Posted by a hidden member.
    Log in to view his profile

    Aug 24, 2007 1:33 AM GMT
    Oh I didnt know DEXA can be used to measure body fat! We only use this for screening osteoporosis... Since X rays only pick up minerals..while MRIs pick up water and fat, how is DEXA used as a measure tool for fat imaging..?

    Love to hear how this works!
  • Posted by a hidden member.
    Log in to view his profile

    Aug 24, 2007 3:45 AM GMT
    Does it have a high rdiation level...? I know that when we order films for our docs (we do this at my facility, they co-sign our notes and test orders) we were told to avoid CTScan if possible because it supposedly exposes you to 700 times the radiation of a single X ray.. I supposed DEXA is also pretty high?

    Again, a question about these more accurate tests when compared to what is floating out there with personal training field...

    Thanks for debunking the myth that there is ZERO correlation between actual and clinical cardiac stress test and the pop Target HR formula of 220-age..

    Are there any comparative studies of hydro, DEXA, and the caliber skin pinch test used by trainers...?
  • Posted by a hidden member.
    Log in to view his profile

    Aug 24, 2007 4:18 AM GMT
    "...Yeah it is the most accurate method.
    The BMI index is also fairly accurate..."

    Be careful of any of the handheld body fat meters you can get commercially. They yield useful results IF you know how they work and their limitations.

    An example is the OMRON Body Fat Tester. It works, according to their literature, by sending a slight electrical impulse through electrodes. Your skin's fat percentage determines it's resistance. So far so good.

    The problem is...that's not the only locus of body fat in your body. As others have pointed out on other threads, your organs have body fat as well.

    So, I tried it. I was a little concerned because it asked me my age. Why would my age have anything to do with what body fat it was going to test? (It also asks other information about height, weight etc.). Then it asks you whether you are an athlete or average. Now why would it ask you that?

    Well, because it is making some (mostly wrong) assumptions about organ body fat and non-skin body fat based upon actuarial tables.

    Sorry for the long post. But I performed an experiment. This 55 y.o. runner (55 miles per week), 5' 10/1/2", 164 lbs, in 30/31" jeans tested at 24% body fat.

    I was aghast. But wait. I put in all the same information, except put my age as 40, and the body fat came down to 16%. Finally, I put in 30 y.o., and it was 11% (which I think is close to correct).

    To make sure I wasn't doing cherry picking, I had my friend Tim, who recently was immersion tested at 5.7% (and is totally ripped out) use the machine and put in his actual age of 39 y.o. He "tested" at 16%.

    Enuf said. I think you can use such devices, but beware if you are an athlete. They are making assumptions based upon the obese general population.

    John
  • Posted by a hidden member.
    Log in to view his profile

    Aug 24, 2007 11:12 AM GMT
    THANKS!

    This is what we need on this site, to debunk popular myths!

    Love to learn more about these things in depth!

    I understand that clinical Golden Standard tests are generally not available to gyms and personal trainers. However, my dismay is the lack of accurate information taught to the majority of personal trainers, and this is then taught to the unknowing public... If the target HR formula and caliber fat measurement are NOT accurate and only gives a gross suggestion, I think trainers SHOULD at least be aware of this and inform the public...?
  • Posted by a hidden member.
    Log in to view his profile

    Aug 24, 2007 11:37 AM GMT
    Like fastprof/John, I have one of those "electrical impulse" body fat meters (my Tanita scale does it). In the morning, it tells me my bodyfat is about 19%. In the afternoon, it's around 14.5%. I've always assumed it wasn't accurate, but I figured it'd at leat give me an idea of how much I've been losing this year...maybe not.

    I'd like to try a Hydrostatic test, but I have no idea where to start to find on in my area.

  • zakariahzol

    Posts: 2241

    Aug 24, 2007 12:08 PM GMT
    Joescorpio,

    That is exactly the brand I used , TANITA. Me and NYC Muscle have a little discussion on this, and obviously this machine is not as reliable as we thought.

    Just like you said the scale kinda flactuated. I could be 3 Kilo heavier in the nite than in the morning. My fat level swing wildly in just a matter of hours. A little bit illogical if you ask me.

    However since I already spend a lot of money on it. I just used the scale as away to roughly estimate my fat content and my weight.
    Frankly I dont thing is that accurate.
  • gwuinsf

    Posts: 525

    Aug 24, 2007 3:07 PM GMT
    I have a Tanita scale at home. I always thought it was grossly inaccurate but after doing my hydrostatic test the other day I came to discover that it was actually fairly close - about 2% higher than what they water test told me. At any rate, what I learned was that my Tanita scale is probably close enough for checking my progress at home and that I'm further away from where I want to be in terms of body fat percentage then closer.

    Joescorpio - I did the test at the gym at my office. A mobile truck with a tank comes out. I know my regular gym also sometimes has the truck come. This is their website: bodyfattest.com
  • swimbikerun

    Posts: 2835

    Aug 24, 2007 3:57 PM GMT
    "Be careful of any of the handheld body fat meters you can get commercially."

    Hey fastprof, I was just talking about the BMI measured with height and weight alone.
  • Posted by a hidden member.
    Log in to view his profile

    Aug 24, 2007 4:00 PM GMT
    Hey swimbikerun, I understand that the BMI is different than body fat. I was just responding to gwuinsf's original query about testing for body fat %.

    I think this is a great thread.
  • Posted by a hidden member.
    Log in to view his profile

    Sep 01, 2007 11:30 PM GMT
    Tanita say in their literature that its best to weigh and do body fat before dinner in the evening because the body has stable water content. In the morning the body is de-hydrated after sleeping and gives a poor body fat reading.

    I always have more body fat in the morning than evening.

    I feel my reading should be less for body fat than around 15.3% but then I probably would!
  • Posted by a hidden member.
    Log in to view his profile

    Sep 07, 2007 11:07 AM GMT
    How does one go about finding a place that will do DEXA body composition analysis? I'm in the DC area - should I call radiology places? Universities? I realize it will be pricy, but I think it would be nice to have an accurate measure once or twice a year to track my long term progress.
  • Posted by a hidden member.
    Log in to view his profile

    Sep 07, 2007 11:52 AM GMT
    thanks for the tip PsychExerSci. I'll check the local universities around Baltimore.