My trip report is one of the places this came up.  I "swim" every day, often morning and evening, and sometimes multiple times after getting to camp if it's hot.  The exception would be when the water is super cold, like in early May.  I put "swim" in quotation marks because it's usually more of a dip or soapless bath, but boy does it do me good.  David and I have even gone swimming in the pouring rain because it feels so good afterwards (and is also kind of cool when you're doing it, too).

When I was in college, grad school, and law school (I was a student forever) I used to swim for exercise, usually a mile a day.  I'm still a decent swimmer so on occasion I'll swim out to a little island or something, but mostly it's just a dip.