I was just asking this, because when I went to a SCUBA class this weekend, I noticed that there was a maybe 250lb man and his 230lb wife, and onother guy with a huge potbelly putting him at about 240lbs. Those people needed more weight to sink themselves to the bottom, they were putting around 12-15lbs on their weight belts, in order to under. When we had to float, or tread water for 10 minutes, it was super easy for them, they just floated there, while I had to actually be kicking and waving my arms the whole time. I felt fatigue in my arms and legs when I was done with that. I knew that I was in better muscular shape and conitioning shape than the fat people at the pool, but they floated almost effertlessly. Thanks for the posts.