Consume water night before
You can drink enough water a night before running to stay hydrated. You will know that you have consumed enough water when your urine is clear or pale yellow. If the urine is dark then you are not hydrated. Do not drink too much so you have to urinate after every 15 minutes to half hour.
Run in better conditions
You should run when the temperature is lower and humidity is less. This will result in less sweating and less dehydration. During humid season, you should run in morning when there is less humidity and temperature is suitable.
Drink when thirsty
In early times, runners were advised to drink in regular intervals during long races. However, with latest research, runners should consume water and other drinks only when they are thirsty. With this way you will know when your body is dehydrated.
You should stay cool while running and you can do this by not wearing nylon or sweat suit. You need to wear clothes from which air pass in order to keep your body cool.
Symptoms which indicate that your body is dehydrated are feelings of dizzy or nauseous. In case you feel these symptoms then you should drink water or other drinks. Sports drinks with electrolytes are highly recommended to keep your body hydrated.
You should know how much weight you have lost after running and should recover it with drinking fluids. Remember to weigh before and after running to calculate the weight lost. And for every loss of weight, you should consume water and other fluids accordingly.
Avoid sugary drinks
You should avoid sugary drinks such as cokes and other carbonated drinks to stay hydrated. Caffeinated drinks should also be avoided when running.