Recently, while running up Pikes Peak I came upon a fellow with good intentions explaining hydration to a woman who was new to mountain running. He said: “You don’t need to carry water with you during the race; they have plenty of aid stations. Besides, most people over-hydrate anyway.” The problem saying this to a novice is that they might interpret this to mean they should not drink very much during the race. If you have run up through the “W’s” on Barr Trail in 85 degree F, you would know what it means to be thirsty! If you are told not to drink very much, you will most likely hold back fluid intake which you will feel the effects of, further up the trail. Perhaps you read the book by Tim Noakes “Waterlogged” and think sports drink companies have persuaded us to drink their products, but even so, I advise caution when making recommendations to other runners. Training status, experience, body composition, sex, and size all play into sweat los and hydration.
The two terms most often used in relation to hydration status are: dehydration and Exercise associated hyponatremia (EAH). Consuming an insufficient amount of water that results in total body water weight loss is a condition called dehydration. Dehydration, or insufficient water status in the body, is important because on average water makes up 60% of our body weight and is tightly regulated to within 0.2 – 0.5% of our daily body mass. A reference range is used because each person’s water mass percentage will vary depending on fluid consumption and body composition. The more lean mass and glycogen stores a person has, the higher the percentage of water in body composition.
There has been debate whether or not dehydration affects performance, and each person’s tolerance to it will vary. Research has covered this topic at length the past several years and on average, performance isn’t compromised until you lose > 4% of your body mass. Many professional marathon runners accumulate much higher percentages of body weight loss than the recommendation without perceived decrement to their performance. However, the physiological adaptations that take place as a result of their training in combination with the elevated threshold for discomfort elite athletes exhibit; make them the minority, not the norm.
EAH can occur when a person is in a state of water balance or water deficit (dehydration), but it is usually associated with excessive water intake. Brought to light in 2002 during the Boston Marathon, EAH isn’t as prevalent as it was then, and if a person consumes an electrolyte beverage when they are thirsty, EAH can be avoided. However, if a person drinks electrolyte containing beverages excessively (as if trying to prevent sweat loss), they can experience EAH. All electrolytes are important which is why you will often see electrolyte drinks include potassium, magnesium and calcium, however, sodium has the biggest impact on performance and perceived exertion. EAH is the extreme end of sodium imbalance, but most people experience symptoms someplace along the spectrum of sodium loss. Ask a triathlete who was sent to a medical tent after a half or full ironman, to receive 2 liters of saline solution, how they felt during the race compared to after their IV. Do you need to take salt tablets running up Pikes Peak? No. Possibly, if you are racing a 14 hour Ironman in Hawaii.
Drinking to thirst, or drinking when you are thirsty is a popular talking point, but I think it is irrelevant for the PPA and PPM because your brain is not functioning as it normally would above 10,000’ which makes the decision to drink or not difficult. Instead, you should have a loose plan of when you will be drinking. If you are depending upon the aid stations its easy. Fueling recommendations for during the Ascent will be different for a professional mountain runner racing the Ascent in 2:30 than someone finishing in longer than four hours. This is because of the physiologic adaptations of their bodies to the environment and training that someone less trained will not have developed. An elite runner is racing at a higher intensity making it difficult to take in as much fluid, but they are spending less total time in the elements.
Get ready for race day by enhancing hydration status by increasing intake of electrolytes the week prior to your event. Increase consumption of foods with potassium and magnesium (kiwi, banana, swiss chard, spinach, beet greens, dried kelp), and low-fat dairy/non-dairy for calcium, or add electrolyte supplement (Nuun or Endurolytes) to your water. Craving salt? Most mineral salts have trace amounts of magnesium and potassium. Replenishing glycogen stores will also enhance hydration status since up to three grams of water is drawn into cells and stored in muscle bound to a gram of glycogen.
On race day, start the morning well fueled and hydrated. During the race drink a carbohydrate beverage for the calories and electrolytes. You do not want to depend on having to actually eat a lot of food. Often, we are more thirsty than hungry and a sweet carb beverage (Gatorade, EFS) is actually what we need. Chews and gels do not provide enough electrolytes per serving if you have a high sweat rate and will be on the mountain for > 4 hrs. It might be relatively cool running up the “W’s” compared to other days when it’s 85’ F and you feel blood bumping in your ears. As you run up Barr trail gaining elevation, your body is trying to cool off by increasing your sweat rate, your heart rate is increasing due to decreased partial pressure of oxygen (pO2), and the lack of oxygen makes you short of breath. This is a lot for the body to manage! As you head into the aspen trees near Bob’s trail, it gets cooler, so you might drink less. By 90 minutes into the race you should have some form of carbohydrate (chews, gel) especially if your effort is higher than it usually is. The aid stations at Barr camp and A-Frame are perfect reminders to eat something. Vomiting increases dehydration and decreases electrolytes, so you don’t want to have an empty tank if you are prone to vomiting above treeline.
The goal of hydration plans is not to prevent weight loss but to reduce the amount of it. Even though I encourage drinking a carbohydrate, electrolyte drink, do not force yourself to drink more than you feel. Measure how much you drink during your training runs up Barr and come up with an estimate for race day. I personally won’t be drinking as much as I normally would because the intensity of the race will be much higher than what I train at. However, to ensure the best training and recovery possible, I will use the same recommendations I am making above. See you on the Peak!