There is much debate about hydration. Opinions vary from those who remember the “good old days” when you just ran a marathon without drinking anything to those who carry their own fuel with them so they can monitor their exact intake during a race. Current research leans more toward the latter viewpoint, but it does not have to be as complicated as measuring everything that goes into your mouth. You do have to think about it, though and knowing how much you need is the first step.
Hydration is important for several reasons. First of all, it is not ideal to get either too little fluid or too much fluid. Both dehydration and overhydration (hyponatremia) have serious consequences including death. Knowing the difference is sometimes hard, because the symptoms are similar. Symptoms of dehydration can include weight loss, lethargy, dizziness, nausea, vomiting, confusion and dry mouth or lips. Symptoms of hyponatremia can include weight gain or swelling, headache, nausea, lethargy, confusion or disorientation. The scary thing is that you often don’t know there is a problem until your symptoms are pretty advanced and it can take some time for medical personnel to figure out exactly what is going on. Also, you can become dehydrated or hyponatremic even after your race is over. Knowing how much you need can help prevent dehydration or overhydration. Another important reason to stay hydrated is that your performance will decrease if you are only 1% dehyrated and it will decrease significantly if you are 2% dehydrated. To put this in perspective, you slow down by about 2% for each 1% you are dehydrated. Obviously, hydration is very important not only for your performance but also for your health. You need to know how to adequately hydrate yourself daily and before, during, and after exercise for safety and optimal performance.
You will feel better during workouts and more energetic overall if you are well hydrated on a daily basis. So, how much fluid do you need? A good formula to use for athletes that are training is to multiply your weight (in pounds) times 0.55 to calculate how many ounces you need daily (you need about half your body weight in fluid per day). Most people have a hard time getting in enough fluid unless they plan ahead and have it available. These days, it is pretty easy to get ahold of fluids during the day-you just have to make a point of drinking them! Beverages that count as hydrating beverages include water, flavored water, sports drinks, tea, decaf coffee (regular coffee neither hydrates or dehydrates you significantly), lowfat milk/yogurt drinks, juice, soda, diet soda, and soups or other foods that contain a significant amount of fluid. Of course, water is the best source and limiting beverages with calories is a good idea if you are trying to lose body fat. The only beverage that significantly dehydrates you is alcohol, so it is not a good idea to have several drinks the night before an early morning run or a race. Save those beers for after the race!
After getting your daily fluid intake down, you need to make sure you are also adequately hydrated before, during, and after exercise to achive optimal performance. Before exercise, most people need 8-16 ounces of fluid 1-2 hours before exercise (if you have time) or 4-8 ounces of fluid 15-30 minutes before you start (if you exercise early in the morning and don’t want to wake up an hour earlier). During exercise, your fluid needs depend on your sweat rate, which is affected by the weather and your genetics. Your best bet is to start within the typical ranges of 4-8 ounces of water or sports drink every 15-20 minutes and weigh yourself before and after exercise to see if you are losing weight or gaining. Then, you can adjust your intake next time, depending on whether you gained or lost weight-the goal is to stay even. After exercise, you need about 24 ounces of water or sports drink for every pound of body weight lost. Since everyone is different, another great way to figure out how much you need to drink is to monitor your urine color. It should be light yellow (not dark like apple juice or clear like water).
It is very important to practice drinking during training so you know what to do on race day. If you have a hard time tolerating liquids during running, you should try to drink small amounts, but start early in the run and drink often (at regular intervals). Many people wait to start drinking until they are well into their run, and your stomach has a hard time absorbing liquids if it is totally empty, which will result in the sloshing around in your stomach. You can remedy this by starting off well hydrated and sticking with your drinking schedule. Again, you don’t want to overhydrate, so monitor your weight and urine color to see what is right for you. This can help you stay out of the medical tent and have your best race!
-Cassie Dimmick, MS, RD, LD, CSSD Registered and Licensed Dietitian Board Certified in Sports Nutrition Achieving Your Best, LLC http://www.achievingyourbest.net/
