This doesn't work for me. I was put on Concerta for 8 years, which essentially eliminated my appetite, so my bodyfat% is low enough that I sink in water unless

This doesn't work for me. I was put on Concerta for 8 years, which essentially eliminated my appetite, so my bodyfat% is low enough that I sink in water unless I take very shallow breaths while keeping my lungs very full (90-100%). Otherwise, my head floats low enough that my mouth is underwater, or I downright sink to the bottom of a pool.