I just have to say that you swimming bitches are hardcore. I consider myself pretty fit, and I can do all kinds of athletic-y things, like hiking Vernal Falls at Yosemite, but I decided to try swimming today. Holy cow!
I was winded after one length, and pretty much had to stop and catch my breath every length thereafter. Ultimately, I ended up going 1/4 mile. Normally I go 16 miles on the bike. I realize you're using more of your body when swimming, but... wow.