It is impossible to overemphasize the importance of proper hydration during athletic events lasting longer than an hour. Improper hydration can lead not only to decreased performance (by up to 50%), but also dangerous medical conditions such as dehydration, heat exhaustion, and heat stroke. It is important that you take the time to learn how to hydrate properly before, during, and after your event.
1 - Closely Monitor Your Fluid Intake
Improper monitoring can, and will, lead to dehydration. Dehydration, the first step towards heat exhaustion and heat stroke, occurs when there is excess sodium, urea, and other electrolytes in the body relative to the amount of water present. Necessary fluid intake varies from individual to individual, and can be greatly affected by such things as body size, level of fitness, effort exhausted, the duration of the event, temperature, and humidity. Generally a good rule of thumb is to make sure your urine is clear to very pale yellow in the days and hours leading up to your event.
2 - Monitor Your Electolyte Intake
Electrolyte needs also vary from individual to individual. Good liquid sources of electrolytes include most sports drinks and fruit juices and should be consumed during exercise lasting longer than one hour.
3 - Dress Properly
People often overdress for endurance athletic events leading to increased body heat, increased fluid loss, and increased risk for dehydration. Two good rules of thumb for proper dressing is to either wear one layer less than you think you'll need, or calculate when you think you'll be finishing your event and dress for the weather/temperature at that time, versus what the weather/temperature is when you begin the event.
4 - Avoid Caffeine and Alcohol
Caffeine and alcohol are both diuretcs (they speed fluid loss, thereby increasing the risk for dehydration).
5 - Hydrate Early and Often
Hydrate at every opportunity, starting early on in your event, and continuing at regimented intervals.
6 - Know the Symptoms
General symptoms include, but are not limited to:
- Deydration/Hypernatremia: Thirst and discomfort, loss of appetite, dry and/or "hot" skin, flushing, headache, visual disturbances, lowered blood pressure, increased heart rate, increased respirations, cramping, fatigue, low endurance, nausea, dizziness, fainting, delirium, and unconsciousness.
- Electrolyte Imbalance/Hyponatremia: Nausea, vomiting, headache, confusion, swelling of the limbs, and stupor.