Hyperhydration: Worth its Salt?
Pre-race strategies to help improve performanceAugust 30, 2011
Photo by srqpix
Ask any triathlete about the importance of hydration, and you’re sure to get an earful. Salt pills and electrolytes are almost as core to our diet as protein, fat, and carbohydrates. Maintaining the balance of fluids and electrolytes in our body during prolonged endurance exercise is key to keeping the negative effects of dehydration and hyponatremia (low sodium levels) at bay.
One strategy athletes may use to accomplish this is hyperhydration—basically, the consumption of glycerol, creatine, or extra sodium leading up to the race in order to increase the amount of fluid in the body. Hyperhydration strategies expand plasma volume, reduce cardiovascular strain seen with exercise, and create a “heat sink” that helps keep the body’s core temperature down and prevent overheating. This method has been repeatedly shown to improve performance for endurance athletes.
The benefit often depends on using the strategy in training and fine-tuning it to fit your needs.
Hyperhydration is controversial due to potential side effects including headaches, feeling bloated due to water retention, and the sheer feeling of glycerol being transported through the stomach. While minimizing fluid loss is often the suggested goal, stories from your fellow competitors of bad experiences with hyperhydration or great performances regardless of their hydration strategy often leave you wondering if the side effects are really worth it. In fact, in a recent study on pre-exercise hyperhydration researchers from the University of Sherbrooke in Canada highlighted the fact that not everyone in their study—despite the positive results they found—benefited from the hydration strategy. One actually got worse! So what’s the answer? Does hyperhydration ever pay off?
Coaches and athletes know that the role hydration plays on performance differs from race to race and season to season. Thus, hyperhydration’s benefits are situational. When attempting to decide whether or not hyperhydration would benefit you for your next big race, consider a few things that will tell you if it’s worth a try:
1) Do you have a high sweat rate?
2) Can your fluid consumption in competition keep up with sweat production?
3) What kind of environment are you competing in? Will it be hot and dry, or humid?
4) Do you have the potential to become dehydrated by more than five percent of your body weight?
If you answer “yes” to any of the above, then you’re an athlete who could probably gain from hyperhydration. The benefit, however, often depends on using the strategy in training and fine-tuning it to fit your individual needs; testing things out well in advance of your competition will be a key part of success. There are multiple approaches for enhancing performance through hyperhydration and each usually has an acute and chronic loading procedure. Over the years, experience has shown that a chronic loading approach is tolerated better by most athletes and it also minimizes the chance for any adverse effects. Here are two solid solutions that should prove beneficial for competition.
Glycerol is a lipid that is metabolized much like a carbohydrate and attracts large amounts of water. Recent research has shown that combining creatine (another substance known for attracting large amounts of water) with glycerol can not only negate some of the side effects (e.g. a headache) but will also enhance total water capacity even more so than glycerol alone. A two-liter solution that provides glycerol at a rate of 1 to 2 grams per kilogram of body weight provides the most effective dose for loading: 11 grams of creatine and 40 grams of a carbohydrate-electrolyte solution (from a powder or gel) per liter of water. Loading with a glycerol-creatine solution should start five days prior to competition. Athletes should drink the solution each night after the evening meal (allow at least two hours between eating and starting to drink) and allow plenty of time for the glycerol to be processed by the stomach prior to going to bed.
Sodium is the primary electrolyte responsible for holding water in the body. The physiologist’s rule of thumb is that water always follows sodium. As a result, increasing sodium in the 24 hours prior to competition can result in a significantly greater amount of total body water if consumed appropriately. The goal of loading is to consume approximately 3,500-4,000 additional milligrams of sodium on top of what you already typically take in on a day to day basis. This can be done through the use of salty foods or through electrolyte capsules with the dose evenly broken up over four time periods throughout the day. Regardless of the approach used, at least 500ml of water or sports drink should be consumed with the sodium at each time point.
Sodium and glycerol can also be consumed on the day of competition, however this is often the method that results in multiple side effects. To load acutely with sodium, athletes consume the 3,500-4,000 milligrams in the one to two hours prior to competition with approximately 20-24 ounces of fluid spread over seven time points. To try using glycerol on the day of competition, athletes should begin drinking a 20 percent glycerol solution in the two-and-a-half hours prior to competition. Initially, athletes should attempt to consume 5 ml/kg of body weight and 30-45 minutes after this consume water at a rate of 5 ml/kg of body weight. At 60 minutes, more glycerol solution should be consumed at 1 ml/kg and again followed by 5 ml/kg of water 30-45 minutes later. This should leave approximately an hour prior to the start of competition for the solution to be absorbed. Most athletes do not like this method because of the discomfort in the gut and it’s important to note that psychologically this can be detrimental.
Krista Austin is a physiologist and nutritionist who consults for the Nike Oregon Project, numerous track and field athletes, USA Triathlon, among others. She recently authored the book, “Performance Nutrition: Applying the Science of Nutrient Timing,” which approaches nutrition from a performance perspective through the intentional use of food to optimize an aspect of human physiology. She’s worked as a physiologist for the U.S. Olympic Committee and as a performance nutritionist for the English Institute of Sport and England’s Cricket Team. She has a PhD in exercise physiology and sports nutrition, a master’s degree in exercise physiology, and is a certified strength and conditioning Specialist. Visit her online at www.performanceandnutritioncoaching.com