Herbal teas do not have caffeine but may contain substances that compete with some medications or that may be unsafe during pregnancy. Check the label of the fruit beverages you buy. Many contain high amounts of sweeteners and almost no nutrients from real fruit. These drinks can give you lots of unwanted calories. For athletes, avoid high sugar or undiluted fruit beverages right before physical activity to avoid stomach cramping.
Water is still the best pre-exercise beverage.
You should drink about 16oz of water an hour before physical activity and 4-6oz right before and for every 15 minutes during activity. Commercial sports drinks will not harm your performance, but show no real benefit over water unless you are exercising non-stop for more than 60 minutes. Because of sweat and water used by the body during activity, for every pound of weight you lose doing exercise, drink back 16oz of water. The goal would be to drink enough fluids before and during exercise so as not to lose any water weight. Do not wait until you feel thirsty to drink.