e. Take salt before and during runs and races of 10k or longer, unless salt is contraindicated by your doctor. Consume salty foods in the days leading up to the run or race, and ingest common table salt before and during your workout or race to maintain the body's water-to-sodium balance. Take on fast-food salt packet at the start of a race. if you're running a half-marathon or marathon, take another packet at the halfway point. After the race, take a sport drink that has some sodium and eat salty foods.
f. Drink for thirst. If you feel thirsty while running or racing, have 4 to 8 ounces of fluid (preferably a sports drink that has some sodium in it at an aid station or whenever you feel you need it). If you aren't thirsty, don't feel compelled to drink. If you can't use thirst as guide, drink no more than a cup (8 ounces) of fluid every 30 minutes. Do not overdrink. Over ydrating can lead to hyponatremia (low blood sodium). This condition can lead to nausea, fatigue, vomiting, weakness, sleepiness - and in most severe instances - seizures, coma and death. Before you run, check the color of your urine. It should be pale yellow, like lemonade. Dark colored urine (like tea) indicates dehydration; completely clear urine may indicate overhydration.
In training, weigh yourself before and after your runs to get a sense of how much to drink to replace the fluids lost. You should aim to weigh the same or no more than 2 percent less after you train. You'll need to drink more in warm, humid weather than on a cool, dry day.
f. Avoid NSAIDS (non-steroidal anti-inflammatory drugs) starting 24 hours before your race. These drugs, which include ibuprofen and naproxen sodium, can limit blood to kidneys, increasing risk of low sodium (hyponatremia). You can start taking them again 6 hours after the race.
g. Don't take anti-diarrheal or cold medicines on race day. These drugs can have dehydrating effects.
h. Always listen to your body - don't overextend. Train sensibly. Increase the distance and speed of your runs gradually, and recover by resting and refueling between hard workouts. Working with a coach or training group can help you stay within safe healthy parameters.
i. Listen to your body. Don's ignore feelings of illness. A sense of "just not feeling right" can be a sign of serious medical problem. The marathon medical team is available at the start, every mile along the course, and at the finish. Most runners who spend time at a medical aid station are able to finish the race.