A study funded by the dairy industry found that chocolate milk help tired endurance athletes recover faster and better than many popular sport drinks. In the study, nine cyclists rode until exhaustion, rested for four hours then biked again. During the rest period they drank either chocolate milk, Gatorade (a fluid/ electrolyte- replacement drink) or Endorox (a carbohydrate replacement drink). The cyclists who refueled on chocolate milk were able to bike 50 percent longer than those who drank Endurox and as long as those who drank Gatorade.
Bottom line: You don’t need a sport drink after a long endurance work out. Milk, regular or chocolate may work just as well. However before a workout a carb/ electrolyte drink may be a better choice.