Is it possible to use a swimming pool to measure body fat? For example, blowing out all the air in your lungs (or as much as possible) and then seeing how much you sink to the bottom of the pool. I suppose once your body exceeds the density of water You will sink. Water is only 1 gram per cubic centimeter, so I'm guessing you don't have to be super lean to sink all the way to the bottom. Maybe 20% Bodyfat? Maybe measuring the speed you sink as well could give additional info on your density. I tried this and I sink all the way to the bottom pretty quickly and can lay flat on my back. Anyone else tried this before? If you've measured your Bodyfat by calipers I'm curious how your pool test results are.