Multisport: Drink To Your Health… And Performance

Originally published in Cyclesport Magazine, April 2004

Written by: Chris Carmichael

Anyone who still had questions about the impact hydration has on performance, had their questions answered during Stage 13 of the 2003 Tour de France, when several days of accumulated dehydration culminated in a crisis that could have cost Lance Armstrong his fifth victory. The weather during the race was unbearable, but if the heat had any positive effect it was to push the importance of hydration back into the front of every cyclist’s mind.

Over the past several months, I’ve been asked most frequently about making the best hydration choices for specific events. The truth is, what you drink matters as much as how much you consume, and both of these variables change as your events or training sessions get longer. Hydration doesn’t begin and end with the fluids in your water bottles though; making sure you’re adequately hydrated prior to starting your workout improves your performance more than anything you eat or drink while on the bike. For most cyclists, this means consuming about a gallon of fluids (128 ounces) every day, which is over a 30% increase over what sedentary individuals need in order to stay hydrated. This gallon of fluids (some of which you’ll get from food) doesn’t include the water and sports drinks you consume during your workouts, and your decisions about fluids during training depend on the intensity and duration of your workout.

The Hour of Power

Training sessions and races that last about an hour are usually very intense; indoor cycling classes offer just one example. As a result of the intensity, athletes tend to sweat profusely, leading to significant losses of both body fluids and electrolytes. A warm environment in a gym during an indoor cycling class, and/or poor air circulation, contributes to even higher sweat rates. Replenishing ones fluids is the most crucial goal when consuming fluids during these short, intense training sessions. Water or simple electrolyte replacement drinks are good choices because they are rapidly absorbed and most athletes find them more palatable during high-intensity exercise.

Carbohydrate-rich sports drinks have been shown to improve performance by sparing muscle glycogen, and they can be helpful during short, hard workouts because the percentage of energy derived from carbohydrate increases with exercise intensity. However, fluids take priority during this type of training session; if carbohydrate drinks give you stomach problems due to the intensity of one-hour workouts, switch to water or an electrolyte-replacement drink. If you’re consuming an athlete’s diet, which is high in carbohydrates, you’ll most likely have enough stored glycogen to make it through a high-quality 60-minute workout.

In order to figure out how much fluid you need to consume during a workout of any length, you need to determine what you’re losing through sweat. The simplest way to do this is to weigh yourself before and after your workout; the difference roughly equals the amount of body fluid you lost. You always want to limit this weight loss to less than 2% of your body weight, as performance diminishes rapidly from more extensive dehydration. This means the post-workout weight for a 165-pound cyclist should be no less than 162 pounds, no matter how long the workout was.

Your goal during a one-hour workout should be to replace at least 50% of the fluids you’re losing. A lot of times, this means consuming 16-32 ounces of fluid, which is about the maximum volume many athletes can handle during intense exercise. While it would be best if you could increase this to at least 80% of what you’re losing, the fact that the workout is over so quickly means your performance won’t significantly suffer as long as you’re replacing half of what you lose. Your training would suffer more if the discomfort of drinking a lot of fluid reduced the quality of your efforts. Either way, after your workout, you should drink an amount of fluids equal to 100-150% of the fluid weight you lost.

Fluids for Mid-Range Workouts

As training sessions increase in length, the sustainable intensity tends to decrease, and as a result, sweat rates also tend to decrease. Both of these factors make it easier for cyclists to replace 80-100% of the fluids they lose during rides lasting between one and three hours. You might still consume 16-32 ounces of fluid per hour, but where that only replaced 50-75% of what you lost during shorter, more intense workouts, the lower intensity of your longer workouts allows this same volume to replace over 80% of your losses. Again, after your workout, you should drink fluids equal to 100-150% of the fluid weight you lost.

Glycogen depletion is a major concern during training sessions lasting more than 90-120 minutes, and ingesting carbohydrate during exercise has been shown to delay the onset of fatigue by slowing the rate of glycogen depletion. As a result, at least half of the fluid you consume during these rides should contain carbohydrate. Drinks that perform the best, like Powerbar Endurance, are 6-8% carbohydrate solutions containing mostly glucose, a little bit of fructose, and electrolytes.

Hydration for the Long Haul

During events or training sessions that last more than three hours, significant glycogen depletion is almost ensured, and ingesting adequate amounts of carbohydrate is essential to optimal performance. Since the average intensity of longer workouts is lower than during shorter workouts, consuming 16-32 ounces of fluid per hour is often enough to replace 80-100% of the fluids you lose through sweat. During the hot days of summer, this is likely to increase to 36-40+ ounces, depending on the individual. Drinks containing carbohydrates and electrolytes should comprise at least half of the fluids you consume, and you should aim to ingest a total of 30-60 grams of carbohydrate per hour. To get that much carbohydrate, you’re almost certainly going to need to eat solid foods and energy gels in addition to sports drinks. With energy gels, it’s important to remember to drink about eight ounces of water or sports drink with them in order to most rapidly absorb the carbohydrates.

Beyond improving performance, optimal hydration is critical for your safety and health. Dehydration seriously hinders your ability to cool your body and keep your core temperature within a safe range. All athletes should learn to recognize the signs of dehydration and heat illness, including elevated resting and exercise heart rates, cessation of sweating, and disorientation. Your health always takes priority over performance, and it’s very important never to let your zeal for competition threaten your well-being. As the hot summer months approach, paying close attention to your hydration is the best thing you can do to ensure you have a safe and successful cycling season.

Chris Carmichael is Lance Armstrong’s personal coach, founder and CEO of Carmichael Training Systems (CTS), and author of “The Ultimate Ride” and “Chris Carmichael’s Food for Fitness” (on shelves June, 2004). To learn what CTS can do for you, visit www.trainright.com.

Copyright 2004 Carmichael Training Systems, Inc.