breathing

I was sure a few hours ago about breathing while swimming.  I proposed that holding my breath underwater and exhaling just before taking a breath would maintain my flotation better than exhaling throughout the stroke.  One website author wrote that holding a breath and would fill the chest making it rise and that the legs and hips would sink.  That seems to be the consensus--what do I know?  My legs are always going to me more dense than my torso, because legs are mostly muscle vs. a mix of gas, fat muscle for the torso.  Wouldn't the legs sink with or without a chest full of air if I don't swim "pressing" down my chest to keep my legs in line?  I'll go to the pool, blow out all my air push off the wall and when I stop gliding, my legs will sink first and fast!

During kicking drills without a kick board, I always noticed how I would sink as I exhaled.  I don't use a kickboard.  I just kick on my back or side.  I'd kick face down, but I haven't a snorkel.

Other benefits of expelling air at the end of the underwater phase of a stroke?: 

1. possibly more oxygen is available to blood flowing through the lungs with a chest of air.   The more air I have in my chest, the more molecules of oxygen--the concentration still drops as I consume it, but more slowly than with me trickling air out during the underwater phase.
2. If more of my head or torso is out of the water, that could decrease the wetted surface area.  I'd love to see a video of myself to know how deep I'm swimming with either kind of exhalation.

I'll be working on the difference between swimming with a gradual exhalation throughout the underwater phase and swimming with an explosive exhalation at the end of the underwater phase of my swim strokes.  More on this later, I hope.