Be sure to stay consistent with the other stuff too! Eat good food so you stay balanced......cruises can be filled with all sorts of buffet-style Vegas feedbags. Find some time each day to meditate or just zone out away from the crowds. Cruises can be busy places so pace yourself. For me, I'd avoid booze so I can stay in the moment and come back the next day fresh and ready for my day on the jet-ski. The risk is I might drive it all the way to Costa Rica.

Have fun!