Your Body's Energy Windows

Exercise physiologists like myself are supposed to be experts on nutrition and recovery. But it took a week-long bike tour in Colorado last summer to make me realize, on a very practical level, how important it is to keep slugging down the food and beverages during day-after-day rides. The Tour of Colorado averaged about 70 miles daily over the high passes of the San Juan Mountains in the scenic south-western part of the state. Not only did we climb nearly a vertical mile each day, we encountered energy-sapping weather conditions including cold rain and sleet—and this was in August!

How did I survive—and enjoy—the ride? A major component was paying attention to proper nutrition. Of course I ate and drank as I rode but I was especially careful to fuel up immediately following each day’s trek. As European stage racers often say, “what you eat today is fuel for tomorrow.” We weren’t racing (although the effort required to get over 11,360-foot Slumgullion Pass made it feel like a race), but our enjoyment and efficiency each day depended on quick recovery from the previous day’s ride, and that’s where the term “glycogen window” comes in. Let’s find out more about this crucial concept in recovery nutrition.

The Window of Opportunity
Studies show that your muscles replace their fuel (glycogen) much faster and more efficiently if you eat plentiful carbohydrates immediately after a tough endurance workout. Your goal is to eat 60 grams of carbohydrate (if you’re an average-sized woman) or 80 to 100 grams if you’re an average male. Your muscles will re-fuel best if you down this chow in the 15 minutes after the workout. The timing is important because the re-fueling process becomes progressively less efficient during the two hours post-training. The reason? The enzyme that stores carbohydrate as glycogen is revved up for about 15 minutes after exercise. The result is increased storage and therefore more energy for training the following day.

The amount of carbohydrate you should eat after an endurance session (60 to 100 grams) is similar to the standard recommendations for how much you should consume before you work out. There’s one exception—research indicates that if you mix four parts carbohydrate with one part protein, your glycogen stores will top off more quickly. One choice—cereal, a banana and some skim milk for protein after exercise. You can also buy specially formulated recovery drinks. See the sidebar for more food and beverage choices.

High Carbo products These beverages are designed to provide the athlete with a generous amount of both carbohydrate and fluids following a hard practice, an intense workout or an explosive match. These beverages are for after activity. They contain a 20 to 25% carbohydrate solution compared to about 6% for drinks designed to be taken during a workout: Recovery Drinks Carbohydrates (grams) Carbo Fuel 40 Gatorlode 47 Ultra Fuel 50 Carbo Cooler 50 Cyber Charge 50 Carbo Power 50 Carbo Force 50 Pro Carb 50 Carboplex 54 Carb Xcelerator 55 Exceed High Carbohydrate 56 Carbo Energizer 59 Paragon Fast Recovery 60

Hydrate After the Ride
No matter how much fluid you ingest while exercising, in hot weather you’ll finish depleted. There’s a simple way to be sure you’re rehydrated—simply weigh yourself before and after exercise and compare the figures. If you’ve lost weight, you’ve sweat out water, not fat. (Darn!) You’ll need to drink 20 ounces of fluid for each pound of body weight you’ve lost while running, walking, swimming or cycling. Keep drinking until your weight has returned to normal, and your urine is plentiful and pale yellow in color.

Food Is Fuel
If you’re training hard—or doing a multi-day event like the Tour of Colorado—eating or taking a recovery beverage within 15 to 30 minutes after exercise is crucial as we’ve seen, but it isn’t enough to ensure you’ll be ready to go again the next day. You also need to eat a high-carbohydrate meal within a few hours. The reason—the 60 to 100 grams of carbo you consumed right after the ride gets converted to glycogen quickly. Soon, your muscles will be crying out for more. So reward yourself with a good meal. On the Tour, we looked for interesting restaurants in each of the destination towns and enjoyed a bit of the local cuisine.

Carbo drinks, snacks, and a big dinner? That sounds like a lot of food, doesn’t it? Don’t worry, you won’t gain weight. Hard cycling or running workouts typically burn from 600 to 4,000 calories in addition to those you need simply to maintain bodily functions and carry on everyday activities. All those post-workout calories are going to energy production, they’re not being stored as fat.