Exercise changes the amount of glucose in your body. During vigorous exercise, the liver releases more stored glucose into the bloodstream. This raises blood sugar. When blood sugar is too high, it can lead to diabetic ketoacidosis. When it comes to hydration, water is the best option for people with diabetes. That's because it won't raise your blood sugar levels. High blood sugar levels can cause dehydration. Drinking enough water can help your body eliminate excess glucose through urine.