Monday, July 14, 2008

Refueling window

I saw this article recently - good information about replacing your glycogen stores.

I Finish, Then Refuel Fast

by Suzanne Girard Eberle, M.S., R.D.

You come in the door sweaty and tired, but glowing nevertheless after finishing a satisfying five-miler. That's after putting in a full day at the office, of course. A hot shower and the recliner are calling you, but the dog needs to be walked, the kids are demanding attention, and your spouse is scampering out the door to a night class. Dinner is a distant dream.

Or perhaps you run with the gang at lunchtime. You have 10 minutes to shower, dress, and become a productive member of society again. Too bad the cafeteria is all the way on the other side of the building.

Refueling after a workout or race is the last crucial step you must take to ensure that you get the most out of your training. Optimal physical performance requires careful attention to both pre- and post-workout meals. If you consistently miss the window of opportunity that exists after exercise to replace muscle glycogen stores, you set yourself up for poor training and racing efforts in the upcoming days.

The physiology behind this phenomenon is simple. Your body stores excess carbohydrate (sugars and starches), primarily in your muscles and liver, as glycogen. Because of this, the carbohydrates you consume on a daily basis influence the amount of muscle glycogen stored. Since muscle glycogen is the fuel of choice for working muscles, your reserves directly affect your ability to train and compete -- especially in endurance events.

Classic studies conducted by exercise physiologist David Costill illustrate the link between carbohydrate consumption and glycogen storage (see the graph above). Repeated bouts of daily exercise accompanied by a low-carbohydrate diet (40 percent of total calories) produced a day-to-day decrease in muscle glycogen. When the same athletes consumed a high-carbohydrate diet (70 percent of total calories), their muscle glycogen levels recovered almost completely within 22 hours of the training bouts. That's an extra boost needed by those runners who train daily. In addition, training efforts are usually perceived as being easier when muscle glycogen is maintained throughout a workout.

Researchers continue to refine the formula for optimum muscle glycogen repletion. A key element is the timing of your carbohydrate injections. A period exists after intense or long endurance exercise where muscles are most hungry for glycogen restoration. This 15- to 30-minute period immediately following exercise appears to be the most important time to consume carbohydrates.

This window can quickly close, though, as you hunt for family members following a race, or stretch, or shower and redress before scurrying back to your desk. Furthermore, since exercise tends to elevate your body temperature, which in turn can depress your appetite, you can't rely on hunger cues to prompt proper refueling.

Post-Exercise Eating Strategies - The most efficient way to rehydrate and begin replacing the carbos your system craves is to drink a sports drink, fruit juice, or (gasp!) even soda immediately following exercise. Aim to consume 50 to 100 grams of carbohydrate (approximately half a gram of carbohydrate per pound of body weight) within the first 30 minutes following a long run or race. If you choose one of the commercial sport drinks intended for use during exercise (Gatorade, AllSport, PowerAde, etc.), be sure to drink an adequate amount after your run. These drinks are less concentrated (14 to 19 grams of carbohydrate per cup) than fruit juices (25 to 40 grams per cup) or soft drinks (40 or more grams in a typical 12-ounce can). Obviously, soft drinks aren't the ideal daily recovery fluid, as they lack nutritional value, but they'll do in a pinch.

Beer is a poor refueling agent. Its diuretic properties offset any hydration effect, and beer provides relatively few calories from carbohydrates (11 to 15 grams in 12 ounces). At postrace celebrations, be sure to reload first with juice, soda, or a sports drink.

The key is to find a drink that agrees with your stomach and taste buds and then begin consuming it immediately. Be prepared away from home by keeping powdered sport drink mixes or small containers of fruit juice on hand. If you are hitting the trails or going to the track, be sure to bring your recovery drink along.

The best recovery plan also includes eating as soon as possible. While it is important to start consuming carbohydrates right after exercise to replace the muscle glycogen you expended, a couple of glasses of Gatorade alone won't do the trick. You need to complete the job by continuing to snack on high-carbohydrate foods every two hours until your next meal. Aim for 50 to 100 additional grams of carbohydrate every two hours. Some healthy choices include an energy bar (4050 grams), four fig newtons and a banana (about 70 grams), or a cup of yogurt with cereal stirred in (about 60 grams).

Robbie Vandervalk, an investment banker in midtown Manhattan, often squeezes in a run at lunchtime and knows all too well the effects of eating too little, too late. He starts off by grabbing water and fruit at the health club following his run, then picks up pizza or a sandwich on the walk back to the office, saving some yogurt for a late-afternoon snack. "If I get caught up with things at work and try to subsist on just yogurt and fruit, I feel horrible a couple of hours later. I could eat for the rest of the day after that, but it doesn't help," explains Vandervalk.

Kristy Jorden, one of the Boulder Road Runners' fastest females (17:41 5K, 36:55 10K), does most of her training first thing in the morning before heading off to work as a physical therapist or spending time with her 19-month-old daughter, Zoie. After working out, Kristy eats a breakfast of cereal, milk, and toast as soon as she can -- "at least within an hour" -- and feels that it sets the tone for the rest of her day. "If I don't eat fairly soon after I run, it screws up my energy for the rest of the day," Jorden says. She keeps high-carbohydrate snacks -- Clif Bars, bananas, bagels, and a powdered sports drink mix -- at work to refuel between clients.

If you've been dragging at work or can't seem to stay up with the pack, you may be underfueling your muscles rather than overtraining. Assuming that you are eating a balanced diet of foods from all five food groups -- runners cannot live on carbohydrates alone! -- experiment with this post-exercise carbohydrate window for a few days. Chances are you'll feel better throughout the day and, more importantly, during that next run.


The " no appetite" blues



  • Anticipate and prepare for a depressed appetite following long or exhaustive efforts.


  • Concentrate on immediately consuming adequate recovery drinkes that provide fluids and carbohydrates: juices, sports drinks, and even soft drinks in a pinch. Taste matters. You'll drink more of it if it tastes good.


  • Ease in high-carbohydrate foods as tolerated. Popular choices include yogurt, fruits, low-fat milk shakes or "smoothies," cereal, bagels, sport bars, and baked potatoes.


  • Satisfy salt cravings with salted pretzels or lite popcorn, soups, low-fat crackers, or salt sprinkled on your baked potato.


  • Resist the urge to wait for your appetite to return. Your muscles' ability to replenish glycogen is greatest during the "carbohydrate window" immediately following exercise. You may end up so hungry later on that you can't make a nutritious choice.

Suzanne Girard Eberle, a registered dietitian, is a former TAC (now USATF) 5,000-meter champion. Along with deciphering the latest nutrition news, she is busy running the trails in Boulder, Colo.
Permission granted to redistribute, as long as you acknowledge the author, FootNotes and the Road Runners Club of America.

3 comments:

Kevin said...

Great article. Darn, I thought beer was always the perfect refueling agent

Anonymous said...

BEER!!!!!
xo ca

Steve Stenzel said...

I agree. I hit the Recoverite hard RIGHT after any hard-ish workout.