A study published in the British Journal of Nutrition stated that low-fat milk is more effective in replacing sodium, potassium, and other vital salts lost through sweat. Subjects who drank milk in the experiment showed no increase of urine excretion even four hours after exercising. However, individuals who drank water or sports drinks showed noticeable increase in their urine output between the first and second hour after exercising.

Guinea pig says…cheers!