Post-exercise nutrition can improve the quality and the rate of recovery after a bout of serious exercise, such as a one hour swimming practice, a weight training session, or a longer run. Signs of poor recovery include fatigue, poor workouts, prolonged muscle soreness, lack of increased strength, and lack of increased muscle mass. Research has shown that nutrition ingested right after working out, and up to two hours later can drastically improve one’s recovery time.
From a physiological perspective, muscle fibers are made of protein and increase in size if the protein is synthesized. Exercise increases the breakdown in muscle protein while decreasing protein synthesis. It also depletes glycogen, which is what the muscles use for energy. Glycogen consists of glucose molecules. Finally, insulin levels are frequently reduced after exercise. Insulin is a hormone that enables the muscle cell to absorb glucose, to build glycogen, and amino acids used to build muscle protein, while decreasing the breakdown of muscle protein during the post-exercise period.
The goal of post-exercise nutrition is to replenish the glycogen stores and to encourage protein synthesis. Carbohydrates are the body’s main source of glucose, the molecule used to build glycogen. By ingesting carbohydrates, you rapidly replenish your glycogen stores. This is important because consistently low glycogen stores lead to a breakdown of muscle protein and a loss of muscle mass. Carbohydrates increase the body’s insulin concentration. Insulin is essential for glycogen and protein synthesis. Carbohydrates also promote the release of growth hormone, which promotes protein synthesis, which in turn leads to increased muscle mass. Finally, carbohydrates decrease cortisol concentration. Cortisol, also known as a “stress hormone,” is released in response to both physical and psychological stress. During a workout, cortisol levels are increased, causing muscle protein to break down.
Several studies have shown that adding protein to a carbohydrate mix will significantly enhance the release of insulin compared to carbohydrate alone. The type of protein most quickly absorbed is whey hydrosylate. Adding amino acids to the protein increases their availability to be used as building blocks. The most important essential amino acid in a recovery drink is leucine, because it works synergistically with insulin to maximize protein synthesis.
The optimal post-recovery nutrition would be a drink consisting of carbohydrates and protein. The optimal form of carbohydrate for the recovery drink is glucose and glucose polymers (several glucose molecules), such as maltodextrin. The ideal protein is a protein hydrosylate, such as whey hydrosylate. The protein should also contain all of the essential amino acids, and in particular leucine. The drink should contain twice as much carbohydrate as protein, calculated at a rate of 0.8 grams of carbohydrate and 0.4 grams of protein for every kilogram of your body’s weight. Most athletes tolerate liquids better than food after a workout. Liquid also has the advantage of replenishing fluid lost during exercise, and is digested and absorbed more rapidly than solid food. Research has shown that if the recovery drink is consumed immediately after exercise, the rate of glycogen synthesis was three times higher than if it is consumed two hours later. Therefore, you should consume the drink as soon after exercising as possible. There are several products on the market that will have this 2:1 ratio of carbohydrate to protein. However, you should read the labels carefully, since most products are only protein with no carbohydrate.