Coach Smith here again - responding to Diane Karnbach. Be cautious about mentioning the article on exercise changes in human milk, as the first study was not well done. (babies rejected the dropper-fed after-exercise milk. They didn't measure babies reaction to the BREAST afterward, only the dropper-fed milk.) Exercise is a normal part of most women's lives, and the milk taste changes anyway because of mom's diet, etc. Many mothers perform heavy manual labor as part of their normal lives and breastfeed just fine, probably better than some sedentary types in western cultures. Subsequent articles debunked the first one, but the first one (suggesting babies rejected post-expercise milk because of the lactic acid in it) got lots of publicity and the ABM companies probably laughed about it all the way to the bank. Hmmm.... if exercise affects the quality of milk (WHICH IT DOES NOT - DO NOT QUOTE THIS!!), I wonder what exercise does to the quality of men's white fluid? If lactic acid supposedly contaminates women's white fluid, perhaps football players need to stop having sex because their sperm might be contaminated with lactic acid. (etc. etc.) Linda Smith, supporter of other jock moms like myself. Enjoy running while you still have working knees, gals! Wear a good jog bra for comfort if you bounce. Avoid racing dives if you're a swimmer - may cause plugged ducts at 12:00 position. Trust me on this.