This video perfectly describes why I will never kayak.
The only time I would ever consider it is if I had a pony bottle, guaranteeing my safety if I were to begin drowning. In fact, I'm curious as to why small air tanks aren't in the recommended kit for rapids.
For those curious: http://www.amazon.com/DXDIVER-Bailout-Regulator-Secondary-Egressor/dp/B00TXN1EVY/ref=sr_1_2?ie=UTF8&qid=1437607236&sr=8-2&keywords=Pony+bottle