Athletes benefit from being well-hydrated and fully fueled going into a competition or workout. A high-carbohydrate meal 2–4 hours before an event or workout, followed by a high-carb snack 1–2 hours before, will top off muscle fuel stores in preparation for the challenge ahead. If you have an early-morning start time, eat the high-carb meal the evening before and consume a carb-rich snack 1–2 hours before the competition. To hydrate pre-exercise, consume fluids with meals and snacks, and drink 14–20 fl. oz. (400–600 ml) of fluid 2–3 hours before your event. Experiment with the timing of your pre-exercise meals, snacks, and fluids during race-paced training sessions so that you can zero in on a comfortable regimen that you can then employ on the day of your event. The intensity and duration of some events, such as triathlons, requires carbohydrate loading to achieve extra stores of muscle fuel. To effectively carbohydrate-load, consume 4.6 grams of carbs per pound (10 grams per kg) of total body weight two to four days before competing.
During exercise, staying hydrated is critical to achieving a strong performance. As you compete, your muscles generate heat that needs to be dissipated in order to prevent overheating. As you sweat and the moisture evaporates from your skin, a cooling effect takes place, but that fluid lost as sweat needs to be replaced. Too little fluid during exercise can lead to dehydration, while too much can result in overhydration. Both conditions impair your ability to exercise, and each can have serious health consequences if allowed to progress unchecked. The key is to practice an effective hydration strategy during exercise.
So, how do you hydrate effectively? One-size-fits-all fluid recommendations are not the way! Sports medicine guidelines recommend that you tailor your fluid intake during exercise to your sweat rate. Click on the PowerBar
Sweat Rate Calculator to calculate your sweat rate and obtain a hydration plan tailored to your specific needs. Even better, calculate your sweat rate in a variety of temperature and humidity conditions. That way, you'll have a hydration plan for virtually any situation that you're likely to encounter.
Calculating your sweat rate is the easy part. The harder part can be drinking enough fluids during exercise to keep up with fluid lost from sweating. Don't despair — a small net loss of fluid is fine, but too large of a loss will hamper your ability to exercise. Definitely avoid gaining weight during exercise, as this is a sign that you've consumed too much fluid. Also, try not to lose any more than 2% of your total body weight during exercise (3 lbs for someone weighing 150 lbs, or about 1.4 kg for someone weighing 68 kg). The 5 lbs (2.3 kg) that you lose during a workout is not fat. It's fluid, it's due to sweating, and it's impairing your ability to exercise. Weigh yourself before and after exercise to see if you've stayed within your 0%–2% hydration zone, and adjust your fluid intake up or down accordingly.
If you consistently fall far short of staying hydrated, gradually increase your fluid intake during exercise. This can train your gut to tolerate more fluid. Also, consume fluids according to your hydration schedule. Athletes who rely on thirst invariably become dehydrated, because feeling thirsty during exercise isn't a good indicator of your body's fluid needs. Instead of relying on thirst, plan to consume fluids at 10- to 15-minute intervals as you exercise.
What kind of fluid is best? For exercise of less than an hour's duration in moderate temperature conditions, plain water is just fine. For exercise lasting an hour or more, or for any amount of exercise in heat/humidity, a sports drink that contains sodium along with carbs is a much better option than plain water. There are a number of electrolytes, or dissolved minerals, found in sweat, but sodium is the most important one — and it should be replaced during exercise, just like fluids, in order to achieve optimal hydration. A well-designed energy gel taken with water can substitute for a sports drink, but make sure that your gel provides a quantity of sodium comparable to your sports drink.
For competitions or workouts lasting longer than an hour, replenishing the carbohydrate fuel that your muscles are burning should be a strong consideration. This is especially true if you're starting exercise following an overnight fast or if there are not sufficient carbs in your pre-exercise meal or snack. Carbohydrates are the primary muscle fuel for endurance exercise, but reserves are limited. Carbohydrates are stored in your liver and muscles in the form of glycogen, which are units of glucose bundled together, and as glucose circulating in your bloodstream. During exercise, as muscle glycogen stores start to run dry, glucose from the bloodstream is tapped as a fuel source. Glycogen in the liver is then gradually broken down to help maintain your blood glucose level. But, eventually, liver glycogen stores also get depleted, and blood glucose can't be maintained. At this point, fatigue sets in, and your ability to perform falls off dramatically. Fortunately, research clearly shows that refueling during exercise can delay the onset of fatigue and extend endurance.
The key to refueling is to consume the right types of carbs, and in the correct amounts. The right types are the simple kind: sources that can quickly be converted to glucose and used as fuel. This is not the time for lots of fiber. What you fuel with will depend on your sport and whether or not chewing is practical. Sports drinks and energy gels, taken with gulps of water, are staples that work for almost any sport. Other good-to-go carb sources include sports bars like
PowerBar® Performance Energy bars, energy chews like the new
PowerBar® Energy Blasts gel filled chews, jam or honey sandwiches made with white bread, low-fat crackers, rice cakes, pretzels, yogurt, and bananas and other fresh fruit. If your sport allows for breaks, a combination of regular food items and sports nutrition products offers the greatest flexibility in meeting your fuel needs. But when chewing is impractical, stick to sports drinks and energy gels taken with water.
A carbohydrate intake of 30–60 grams per hour is the standard recommendation. However, according to just-published research, the new state-of-the-art for refueling during exercise is a 2:1 mixture of glucose and fructose, as is found in PowerBar sports nutrition products that feature
PowerBar® C2MAX dual source energy blend. If you're consuming PowerBar C2MAX carbs, you can take in as much as 45–90 grams of carbohydrates per hour. This higher rate of refueling can be especially important in long-duration events, when carb refueling is absolutely critical. As always, experiment during training sessions to find the carbohydrate refueling regimen that works best for you.
References:
Burke L. Fluid and carbohydrate intake during exercise. In: Burke L, Deakin V. Clinical Sports Nutrition. 3rd ed., McGraw-Hill. 2006; 385–Z414.
Topics:
Hydration, C2MAX, Energy
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