Hydrostatic Body Fat Testing

sijomial wrote: »

Personally I find the text commentary on Builtlean more useful than the female pictures as there's a lot of variance in how people carry their muscle and fat.....

"Body Fat Percentage Women 15-17%
This is still considered a very low body fat for women, which is similar to the 6-7% body fat for range men. Many bikini and fitness models will reach this body fat level and some may not be able to menstruate. Muscle definition in the abs, legs, arms, and shoulders is apparent, there is some vascularity and some separation between muscles. Hips, buttocks, and thighs generally have a little less shape because of the low body fat."

I'm also not terribly convinced if someone is aspiring to a certain look and getting reasonably lean that body fat testing with uncertain accuracy is any more helpful than the mirror (backed up with progress photos). You look to be at that point where small reductions in fat and/or increases in muscle bring very clear changes. e.g. muscle definition starts to show more clearly.

sgt1372 wrote: »

I've had many hydro and DEXA tests done at the same time over a 5 yr period, as often as quarterly, in the past.

I did both hydro and DEXA initially because I wanted to compare the results for comparative validity.

What I found was that the hydro and DEXA results varied similarly (up/down) but that the hydro results were always lower than DEXA by about 2-3%.

The main error factor in hydro is how much air you can expell air from your lungs. Air causes you to float (as does fat). So, if you do not expell as much air from you lungs as possible, your BF% will be higher.

The operator of my hydro tank said that some ppl obviously can do this better than others. In my experience, you have overcome a feeling of "drowning" or "suffocation" to get as much air out of your lungs, which is easier said than done

You can try to train yourself to do it by spending some time w/your face under water in a pool or bathtub while trying to blow the air out of your lungs.

But, f you can't expell enuf air from your lungs no matter how hard you try, I suggest just getting a DEXA test instead which is far easier to get do (all you do is lay under the moving arm of the scanner).

DEXA also provides much more data than hydro, like bone density, bone vs muscle mass wt, BF distribution by body areas and VAT. Hydro will just give you a total BF%.

Frankly, the only reason I kept doing hydro, even though it provided less data than DEXA, was because It gave me consistently lower results than DEXA.

LOL!