Headaches can indicate that a person is dehydrated, so if you get these headaches, you need to be sure that you are drinking enough before, during and after your runs. Take water with you if needed, but mind that you do not typically need to be one of those people that carries the full gallon jug to work and then the gym. You don’t typically need to bring water when the run is under an hour or it is cooler out, but your mileage may vary. Longer runs mean you want to try to drink 3 to 6 ounces of water every 30 minutes of the run. You should be needing to urinate every couple of hours and the urine should look like diluted lemonade. Dark yellow means you need more water. Running in the early morning might mean that you need to monitor your hydration the night before and drink 8 oz. in the morning before you take off. Making note of your time, pace, air temperature, humidity and how much you consume can help you plan out what you need when it comes to race time.