The Best Time to Replenish Glycogen & Exercise

Carbohydrates have been center stage in the media for some time now. They tend to be vilified in the nutrition world, but many people don't realize that their bodies run on carbohydrates. Your body relies on carbohydrates -- in the form of glycogen -- to get you through that grueling spin class or your favorite workout video.

Glycogen is necessary for optimum performance. (Image: Brand X Pictures/Stockbyte/Getty Images)

Glycogen Is Fuel

Glycogen is a polysaccharide that serves as an energy storehouse. Glycogen is found in the liver and muscles. The muscles convert glycogen into usable energy and your body utilizes your glycogen stores throughout the day. This is why it's important to maintain proper nutrition to keep those stores replenished. With exercise, those stores are quickly depleted. Your body stores enough glycogen to last 12 to 14 hours of daily activity. That same amount of glycogen will get you through two hours of sustained exercise. While the body uses glycogen at the beginning of any exercise, the body will eventually use fat stores for energy, but glycogen is required to convert the fat into usable energy. Glycogen is the fuel in your gas tank that you need to keep going.

Time To Nosh

Ideally, you'll replenish your glycogen stores within 15 minutes of completing your workout. If carbohydrates are consumed immediately after exercise, the body is able to retain up to 50 percent more glycogen. Depending on the length of exercise and muscle fibers involved, it can take between 22 hours to four days to completely replenish your glycogen supply. The maximum window for “best-case” glycogen replacement is two hours post exercise.

Keeping The Muscles Primed

The consequences of not replenishing the glycogen stores are dire. If not properly fed, the body will start consuming muscle in order to fuel itself. Before a lengthy athletic event like a marathon, participants will often “carb-load.” The purpose of this is to make sure the glycogen stores are completely full so the body doesn't turn to alternate sources of fuel. Glycogen replacement is essential to the body's reparative process.

Quality Over Quantity

A post-workout meal doesn't need to be large. Generally, 150 to 250 calories of quality food will suffice. A meal consisting of an equal ratio of carbohydrates and protein is the best choice. Avoid meals with a high fat content, as fat slows digestion and delays the delivery of much needed nutrients to your muscles. Suggestions for meals include protein shakes, eggs and orange juice, tuna fish sandwiches, bananas, low-fat yogurt and oatmeal with fresh fruit.