I am helping a guy start kayaking and we were talking about clothing options and I told him that I wear a drytop with layers underneath and depending on temp's I wear fleece underneath. I had pointed out that he could use hydroskin or some sort of wetsuit fabric underneath but that I did not. He brought up that it seemed like fleece would absorb some water and weigh you down if you swam and hydroskin/wet suits would not. I had never really thought about that and wondered what everybody else wears to insulate and their thoughts....