Training: The Muscle Recovery Window

Written by by Matt Fitzgerald

What you eat and drink in the first two hours after a workout is just as important as what you do in the workout itself. This is because the whole purpose of a workout is to stimulate specific physical adaptations. But these adaptations do not occur during the workout. They happen between workouts, and especially right after them, during the so-called "acute recovery" period.

Nutrition is the primary determinant of the outcome of this critical short-term muscle recovery process. Athletes who consistently take in the right nutrients in the right amounts during the "muscle recovery window" will recover faster, adapt more fully, and eventually wind up far ahead of those who consistently do not.

There are four categories of nutrients you need to consume as soon as possible after every workout: water and electrolytes, carbohydrate, protein, and antioxidants. Let's take a closer look at each category.

Water and Electrolytes
During exercise, body fluid comprising water and electrolyte minerals (sodium, chloride, magnesium and potassium) is expelled from the body through sweating. Consuming a sports drink containing water and electrolytes during exercise is an effective way to limit fluid losses. However, it is seldom possible to restore water and electrolytes as quickly as they are lost during moderate- to high-intensity exercise. Therefore, even athletes who are conscientious about hydration nearly always complete their workouts in a state of fluid deficit. This phenomenon is known as involuntary dehydration.

Athletes routinely compound the problem of involuntary dehydration by failing to consume adequate quantities of water and electrolytes immediately following exercise. As a result, their blood volume stays low, which in turn slows the delivery of vital nutrients to the muscles and the removal of metabolic wastes from the muscles. The whole recovery process is thereby compromised.

In order to ensure adequate restoration of water and electrolytes, in the first two hours after exercise you should consume 1.5 ounces of water and/or a sports drink for each ounce of weight loss incurred during the exercise session. If you choose to drink only water, be sure to supplement it with electrolyte-rich foods like fruits or vegetables.

Carbohydrate
The primary fuel source for moderate- to high-intensity exercise is glucose derived from dietary carbohydrate and stored in the muscles and liver in long chains called glycogen. The longer exercise continues, the more depleted the body's supply of this energy source becomes.

As with water and electrolytes, it is possible to slow the rate of glycogen depletion through the intake of a sports drink (containing carbohydrate) during exercise; however it is not possible to halt it entirely. After exercise, the sooner you begin to replenish muscle glycogen by consuming carbohydrate, the better. This is because, following exercise, the muscle cells are much more receptive to insulin, the hormone responsible for transporting glucose through the bloodstream to the liver and muscles, where it can be stored as glycogen. The body can synthesize glycogen two to three times faster during the first two hours after exercise than it can at other times.

How much carbohydrate is needed? As a general guideline, athletes should try to consume 10 to 20 percent of their total daily carbohydrate intake during the first two hours after exercise. Many athletes find it most convenient to begin getting their post-exercise carbohydrate by simply continuing to drink the sports drink they used during the workout. Most sports drinks provide the water, electrolytes, and carbohydrate the body needs for recovery.

Also, it's often much easier to drink than it is to eat a full meal soon after exercise. But if you are hungry, carbohydrate-rich "real" foods will do the job just as well.

Protein
Although not a preferred fuel source, proteins (actually, amino acids) are used to produce some energy during strenuous workouts when carbohydrate fuel runs low. These amino acids come primarily from the breakdown of muscle proteins. Also, the normal process of protein building is virtually shut off during workouts.

Because protein is an important structural element of muscles, protein breakdown during exercise leaves the muscles in a weakened state afterward. In order to properly recover from and adapt to this particular training stress, athletes must act quickly to rebuild muscle protein. Timing is as important for protein rebuilding as it is for glycogen replenishment, and for the same reason. Insulin is responsible for delivering both glucose and protein/amino acids to muscle cells. And as I mentioned, the muscle cells are extraordinarily sensitive to insulin during the first two hours after exercise.

How much protein do you need? About 1 gram of protein for every 4 grams of carbohydrate is optimal. You can get this approximate balance of macronutrients from a wide variety of food options, from certain performance recovery drinks to a hearty breakfast such as a vegetable omelet and toast with fruit spread, washed down with orange juice.

Antioxidants
A major cause of post-exercise muscle soreness and weakness is oxidative stress, or free radical damage. Oxygen is a highly reactive type of molecule - a free radical. During intense exercise, an athlete's rate of oxygen consumption increases dramatically. Many of the individual oxygen molecules consumed during exercise try to become more stable by pilfering an electron from living tissue - often a muscle cell membrane - and thereby damage the muscle cell.

Fortunately, antioxidants such as vitamin E are able to protect body tissues by neutralizing free radicals. Research has shown that athletes who take in healthy doses of antioxidants after exercise experience much less free radical damage than those who do not. Antioxidants are plentiful in many fruits and vegetables, and a growing number sports drinks and performance recovery drinks contain them.

In Summary
If you're serious about your athletic performance, don't just do the right workouts. Get the most from each training session by practicing proper post-workout nutrition habits. Hydrating, replenishing energy stores, and rebuilding your muscles should be your first post-exercise priorities - after a nice hot shower, of course.

Matt Fitzgerald is the author of Triathlete Magazine's Complete Triathlon Book (Warner, 2003). He trains triathletes and runners online through Carmichael Training Systems (). Email him at fitwriter@hotmail.com.

Visit Carmichael Training Systems at: TrainRight.com.