Short, high-intensity workouts can have a significant impact on your willingness, ability, and need to consume food and fluids while you’re on your bike. In particular, hard workouts inhibit your desire and your opportunities to consume either food or fluids, which is part of the reason that your pre-workout snack is so important. Fortunately, because of the amount of glycogen you can store in your muscles and the fact that you can only process and utilize about 1–1.4 grams of ingested carbohydrate per minute anyway, there is little need to consume any calories during a 1-hour workout.
Let me make an important distinction: If you’re planning on having a good ride that lasts more than about 75 minutes, you need to consume carbohydrates within the first 30 minutes on your bike. But if you’re going to be done with your hard efforts and either off your bike or into your cool-down within 60 to 75 minutes, you can complete a high-quality training session without consuming a single calorie on the bike. Will your ride be even better if you use a sports drink or a gel during a 1-hour workout? Maybe, but it depends less on the calories themselves and more on what you can tolerate.
Water is the one thing you can’t do without during even a 1-hour training session. Depending on the temperature, humidity, and your personal sweat rate, you can lose up to 1.5 liters of fluid (about 50 fluid ounces) in a 1-hour workout. To make matters worse, high-intensity workouts increase core temperature more than low- to moderate-intensity rides, especially if you’re riding indoors, and sweat evaporating off your skin is your body’s primary cooling system. Sweating out up to 1.5 liters of fluid and failing to drink will absolutely hinder your performance, resulting in lower power outputs for your intervals and a shortened time to exhaustion.
Carb Consumption on Short Rides Versus Long Ones
|Ride length||Carb intake|
|75 min. or less||None necessary; drink water|
|75 min. to 2 hrs.||Electrolyte drink or 1-2 gels|
|2 to 5 hrs.||Carb and/or electrolyte drinks, water, gels, solid foods|
|5+ hrs.||Taste, texture, and variety increase in importance|
You also lose electrolytes as you sweat (primarily sodium, but also some potassium and traces of other minerals), so you’d ideally consume a sports drink during even short workouts, but again we have to go back to the concept of tolerance. Studies, including one published in 2004 by Dr. Ed Coyle, have shown that as exercise intensity and core temperature increase, athletes gradually lose their drive to drink and eat. Anecdotal evidence not only supports this but also shows that many athletes experience an upset stomach when they consume calories during very hard workouts. At the same time, adding carbohydrates and sodium to the fluid increases an athlete’s motivation to drink and increases the amount of fluid you consume every time you lift your bottle to your lips. And the American College of Sports Medicine recommends consuming 500 to 700 milligrams of sodium per hour of aerobic exercise.
I recommend trying to find a compromise that works for you. Many athletes can tolerate electrolyte solutions and lightly flavored carbohydrate/electrolyte sports drinks. Few athletes have any desire to consume energy gels or solid foods. For short workouts, caloric replenishment is not necessary, but the need for electrolytes and fluids means that a sports drink is a good idea for high-intensity workouts as long as it doesn’t upset your stomach.
What the heck is in my sports drink?
A sports drink is essentially water with stuff dissolved in it. Some drinks have lots of different kinds of stuff dissolved in them, most of which just waste space. There is only so much room to dissolve solutes in a drink, and drinks with fewer ingredients can use more of that room for important things such as carbohydrates and sodium. The simplest drinks are the best because they are easiest on the gut and are better at facilitating the transport of sugar and electrolyte across the semipermeable membrane of the intestinal wall.
The concentration of sports drinks is important. When you change the osmolality of the fluid (the total molecular concentration of everything in the drink—carbohydrate, electrolyte, flavoring, additives—per unit volume), it changes how the drink influences the overall mixture in your stomach, and hence how that mixture makes it into the intestine. Sports drinks are formulated to optimize the absorption of carbohydrate, fluid, and electrolyte. If the osmolality of the sports drink is too high because of a bunch of additives, it may contribute to slower gastric emptying. When the osmolality of sports drinks is lower it is more likely to contribute to faster gastric emptying (depending on what else you’re eating and drinking), and if it’s being consumed on an empty stomach it is formulated to get into the intestine quickly.
If you are designing a sports drink to have a relatively low osmolality but you want it to deliver moderate to high amounts of sodium and/or carbohydrate, you have to eliminate other stuff to make room. That’s a big part of the reason we’ve seen drink manufacturers shift to drinks with shorter ingredient lists.
The ingredients, primarily sugar, sodium, potassium, and flavoring, are in the drink for good reason. Putting electrolytes and flavoring into a fluid makes you want to drink more frequently and consume more fluid each time you drink. There’s actually a lot more to the way your sports drink tastes than marketing mumbo jumbo. A lightly flavored drink is preferable to a stronger one because when you consume half a bottle in one long slug, the stronger-tasting drink becomes overwhelming and you stop drinking. A drink that tastes almost watered down when you are at rest will taste just about right when you are exercising. This is why athletes have long diluted commercial sports drinks like original Gatorade, which these days are often flavored to appeal to convenience store customers instead of athletes.
Even taste components and mouthfeel are important. A slightly tart drink will encourage you to drink more than an overly sweet one, and citrus flavors also increase the drive to drink. It should be no surprise, then, that almost every drink company has some version of lemon-lime and/or orange in its product line. In addition to the flavor, a sports drink needs to clear the mouth well. When a drink leaves a film in your mouth, as is often the case with overly sweet drinks, it’s not only unpleasant, but you’re not likely to drink again soon.
Rather than dilute sports drinks, it is better to find a drink with a lighter taste so you can comfortably consume it at full strength. The reason you don’t want to dilute heavily flavored commercial sports drinks isn’t because doing so lowers the concentration of sugar in the drink, but because it reduces the sodium concentration. Again, this is relative to all the other foods and fluids you are consuming, but if you are consuming a sports drink with the primary goal of staying hydrated—that is, maintaining proper fluid and electrolyte levels—then consuming a watered-down drink provides a lot of fluid and reduced sodium, which over time could contribute to inadequate sodium replenishment in relation to fluid intake.
Ideally, while riding you’ll consume enough fluid to replenish at least 80 percent of the water weight you lose by sweating. That’s often not a problem during moderate-intensity tempo rides, but it becomes difficult when you’re in the throes of repeated sets of power intervals. That’s OK, and the relatively short nature of your workouts should be taken into consideration. The fluids (and electrolytes) you consumed before your workout will help ward off dehydration during short workouts.
The bottom line is that if you consume nothing else during your hard interval workouts, make sure you drink water. Aim for at least one full bottle over the course of an hour, and follow the hydration recommendations in the post-workout nutrition section to make sure you replenish what you’ve lost.
Adapted from The Time-Crunched Cyclist, 3rd edition, by Chris Carmichael and Jim Rutberg, with permission of VeloPress.