Insulin and Recovery

Of all the hormones in the body, insulin is one of the most important.  Although diabetes education seems to simplify the production and effects of insulin, it is actually a complex hormone that is very important in nourishment, growth, and recovery.  

In general, the body's metabolism, the sum of all the biochemical processes occurring, can be described as either anabolic or catabolic.  When the body is in a state of anabolism, it is in a state of growth.  Anabolism is the building up of complex molecules, resulting in the creation of new cellular material, such as enzymes, proteins, cell components, or tissues. It is necessary for tissue growth, maintenance, and repair. 

The body needs extra energy in order to be in an anabolic state.  Conversely, catabolism occurs when the body is forced to use its own tissues for energy; it is the breakdown of larger and more complex molecules into simpler ones for energy production, excretion, or recycling of certain compounds.  When catabolism exceeds anabolism in the body, it translates to a net loss of complex molecules.

Insulin is characterized as an "anabolic" hormone because it promotes synthesis, the synthesis of glycogen (carbohydrates), triglycerides (fat), and proteins.  Produced by the beta cells in the pancreas, the secretion of insulin is an example of a negative feedback system.  Eating a meal results in an increase of glucose, amino acids, or certain hormones in the blood stream; all of these stimulate the beta cells to release insulin.  The insulin allows for the cellular uptake of the nutrients in the food, which will provide the cells with the essential material they need to grow and repair.

Most generally, insulin "opens" cells up to the nutrients in the blood stream.  Because of this, it is often associated with fat storage.  In fact, some people believe that it should be avoided because of its potential to store fat.  However, insulin is works in all the cells of the body, including the muscle cells.  In muscle tissue, insulin increases glucose uptake by the cells, filling glycogen stores.  (As a result, in the liver, it decreases the breakdown of glycogen stores into glucose, thus inhibiting glucose synthesis.)  It also increases the cellular uptake of amino acids, which leads to protein synthesis. 

The anabolic effects of insulin in the muscle cells is particularly important for athletes, as manipulating insulin levels can have a direct impact on strength and recovery.  A strenuous workout depletes amino acids, glucose, and glycogen stored in the muscles, essentially leaving them "empty."  For this reason, it is recommended to eat a combination of carbohydrate and protein following a workout.  However, taking enough insulin is a key component of post-workout nutrition.  Spiking insulin post-workout ensures that the muscle cells uptake the glucose and amino acids that they need to refuel and repair, thus improving recovery.  The faster the muscle cells can get the materials they need, the sooner they can begin the anabolic processes of rebuilding and strengthening.