Do your calves cramp? Make sure you are well hydrated, and try to drink continuously during your swim workout. Keep a water bottle at the end of your lane, if you can. You may be low on potassium, so eat your bananas!
Fish Fuel Out of the water, nutrition for swimming performance isn't markedly different from nutrition for running, hiking and cycling. You still need sufficient carbohydrates to fuel the workout and to reload in preparation for the next one.
Still Kickin' Past 50 A feature showcasing dedicated Master's swimmer Jack Geoghegan, excerpted from Swimming Past 50. Piece includes one of Jack's sample workouts.