The question came up when I saw a post on dailymile about a 50k HAT beer. Personally, I find the lower alcohol, lower carbonation (smoother) beers to be very refreshing after a run. Even cheap commercial beers can be very refreshing after a run (e.g. Coors, PBR) Has anyone dedicated a homebrew recipe specifically towards sports?
There's a place in Portland (surprise) called Hopworks: http://www.hopworksbeer.com/
When I was there a few years ago they had a beer for road bikers that was part wheat, part lemonade and I believe a few pinches of salt. I know some people use Wheat beers with Gatorade - but that sounds kind of disgusting to be honest :).
If I had to fashion a recipe off the top of my head...
4lbs 2-row (or 4lbs of extract) 1lb honey malt
1oz Northern Brewer 1oz Tettnanger (40 mins in) 1oz Goldings (last 5)
I'd use an easy on the palette yeast - maybe an ESB.
When you cut to the second stage, slice up some fruit sangria-style: lemons, limes, pineapple (whatever you like) and pop them into mesh bag. Not sure how many - maybe one lemon, one lime, 3 cuts of fresh pineapple.
When the fermentation completes you could add water if the fruit's too strong. I would then add some minerals for hydration and some salt. I think the salt will be the thing that makes it - your body craves it when working out.
If you can do lagers I'd say to replace the above recipe with a nice Czech pilsner. MM
Maybe a Berliner Weisse? Light, refreshingly tart, and not enough alcohol to contribute to dehydration in a significant way.