I bet that water was still a mite chilly. However, it did give me a good idea.
My old knees sometimes get pretty achy working at the farm. I think I should follow your example and just sit on a sandbar in our creek and soak my knees for about ten minutes. Towel off and go back to work.
Heck, the minnows in the creek might even give me a pedicure at the same time.
