The glycogen window
When I was a kid, the sirens from Kill Bill would often start ringing when a coach would say something but not explain why. When it came to the “glycogen window” the questions coming at them would be: What do you mean? Why do I need to eat within 20mins? Why? All of which went unanswered back then, probably for the sake of preventing a never-ending conversation.
As is popular knowledge, food consumption should occur within <20mins post-exercise for optimal recovery. After this time frame, nutrient absorption takes significantly longer. Why? In short it’s due to insulin production, which helps with the regulation of blood sugar and its transportation into muscle and liver cells.
During exercise, cells undergo a process referred to as catabolism where summarily, fatty acids and glucose are broken down into acetyl-coA, which then enters the TCA cycle and electron transport chain yielding energy for biologic work.
Insulin is released in greater amounts by the pancreas to combat this, providing cells with the opportunity to replace lost nutrients at a faster rate (insulin brings nutrients in). This is the “glycogen window” and it diminishes shortly after exercise ceases. To take advantage of its benefits, athletes must consume the required nutrients during exercise and within the small time frame available post-exercise.
Athletes should ideally be trying to consume foods that meet their post-exercise protein/carbohydrate requirements (to be discussed next week). WPI drinks and chocolate milk have been found to be extremely useful due to their wide availability and the <time required for digestion however, nothing beats a proper meal (to be discussed next week).
- Cycling Time Trial Performance 4 Hours After Glycogen-Lowering Exercise Is Similarly Enhanced by Recovery Nondairy Chocolate Beverages Versus Chocolate Milk.
- Guidelines for daily carbohydrate intake: do athletes achieve them?
- Nutritional practices of male and female endurance cyclists.
For more articles on this topic, be sure to head through to PubMed.