1. Know your sweat rate. This will help you estimate how much fluid you’re losing during a workout or race. If you have a high sweat rate, you might need to replace electrolytes more often than you need to take in carbohydrates. This will help your overall performance and keep cramping away. To determine your sweat rate, weigh yourself (in your birthday suit) before and after workouts. The weight loss experienced will give you an estimate of how your sweat rate and provide a goal for both re-hydration post workout and for how much fluids to take in during your next workout.
2. Hydrate before your race. Don’t wait until the night before your race to start your hydration plan. Start about three days before the event. As you taper for a race, your body will store more water and electrolytes, but you will still need to drink both water and fluids with electrolytes. Salty snacks can also help your body store water if you’re wanting to drink less sports drinks. Also, if you’re feeling thirsty or your urine has a moderate to strong yellow color at any point during the days before your race, you’re too dehydrated.
3. Know the signs of dehydration. Hammer Nutrition has a great article on hydration and includes a chart that shows the symptoms of what your body experiences by percent of body weight water loss.