Everything You Need to Know About Glycogen

Your primer on the foremost fuel you need when you want to go fast. – By Selene Yeager


“Glycogen is gold.” Those are the words of Iñigo San Millán, PhD, of The University of Colorado Sports Medicine and Performance Center (CUSM&PC) in Boulder, Colorado. Hyperbole? Perhaps. But fact is you can’t win gold—or even go for it—without this precious resource. And if you ever find yourself fresh out of glycogen when you’re kilometres from nowhere, you’d likely be willing to pawn anything you’ve got on you for just a bite of amazing, life-saving, pedal-powering carbohydrate—the source of this crucial energy-producing resource. Here’s why.


What Glycogen Is

Stored glucose and carbohydrates, found in your muscles, liver, and brain.


When You Need It

Always. Even when you sleep. (When you wake up, your liver glycogen is about 50 per cent depleted). During low-intensity activities, however, you burn mostly fat. As you ride harder, your body switches over to mostly to glycogen.


How Long Your Glycogen Stores Last

You burn about one gram a minute, just riding along; about two grams a minute at endurance pace, and three grams a minute at race pace. So most people will start to tap out their glycogen supply after 1:45 to two hours. Repeated high-intensity efforts can drain your stores more rapidly.


How Much You Have

Between 350 and 500 grams, or about 2,000 calories’ worth if your stores are fully stocked. About 80 per cent of that is stored in your muscles; the rest is stashed away in your liver.


When You Hit Empty…

You bonk. That means slowing way down. Your body also becomes catabolic as your muscle tissue breaks down protein and amino acids to make glucose, essentially “eating itself to fuel itself” says San Millán. That can lead to undue muscle damage and set you back in your training because damaged muscle tissue doesn’t store glycogen well. So you’ll be going out for your next big ride with limited stores until you fully recover.


How to Maintain (and Maximise) Your Glycogen Stores

Eat a diet that is sufficient in carbohydrates. That amount, of course, is based on how active you are.

While you’re riding, take in carbs to keep your tank topped up. Aim for a minimum of 30 to 60 grams an hour on long rides. If you’re going to be out there more than four hours—especially if you’re going hard and/or going really long—aim for about 80 grams of carbs an hour

Eat a carb-rich recovery shake or snack within 30 minutes of finishing a race and/or hard ride. That’s when your body is primed to restock your glycogen stores. Include some protein, which helps speed glycogen storage and muscle fibre repair.

Finally, building a strong endurance base will help you be a better fat burner at higher intensities. Since even the leanest riders have abundant fat stores that means you can ride longer and harder before you burn through your limited glycogen supply.

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