Post by Tim Wescott on Jan 11, 2005 15:58:04 GMT -5
For all those people, on all those boards, who ask if they should train when sick!!! ;D
Weight Training and Illness
What Does Weight Training and Critical Illness Have in Common? - by Joseph Rossi MD
Both create excessive metabolic demands on the body. Both promote negative nitrogen balance. Both require optimum nutrition for the best chance of survival. In critically ill patients, the metabolic demands can increase 200% to 300%. This includes both caloric and protein requirements.
Simply supplementing calories in this setting results in negative nitrogen balance, muscle wasting, poor wound healing and overall poor outcome. During periods of critical illness and stress; the body functions in an environment of counter-regulatory hormone excess including cortisol, adrenaline and glucagon.
These hormones are necessary for survival; however, they are catabolic and create high levels of negative nitrogen balance.
Protein excretion is increased in severe illness. In trauma patients and those with severe body burns, it can reach 250 g/day. The major role of increased rates of protein degradation during metabolic stress is to provide amino acids, especially branched-chain amino acids which donate nitrogen for the synthesis of glutamine.
This glutamine, after release by the muscle, is essential for functioning of the immune system amino acids during periods of injury and stress is skeletal muscle. Under metabolic stress the muscle and plasma concentrations of glutamine decrease. it has been shown that there is a correlation between the concentration of glutamine and the rate of protein synthesis. The overall result is skeletal muscle breakdown to provide metabolic control during periods of high stress.
Also, it helps to explain why there is such a large increase in protein degradation in skeletal muscle during injury and stress and indicates that it is essential for the survival of the body under normal conditions. This is a similar situation to that found for the effects of physical training on skeletal muscle.
Several studies have indicated that the use of branched-chain amino acids improve nitrogen balance during injury and stress. This is also suggested for glutamine. By directly supplementing glutamine and branched-chain amino acids, the signal for skeletal muscle breakdown may be inhibited.
Also, branched-chain amino acids and glutamine may directly stimulate muscle protein synthesis. Improved nitrogen balance has been reported in bone marrow transplant patients, burn patients, and those undergoing major surgery.
In addition, glutamine has been shown to increase both growth hormone and insulin levels. Heavy resistance training creates a similar environment to that of the critically ill patient. High levels of cortisol and adrenaline released during training inhibit protein synthesis and create negative nitrogen balance.
These effects can persist for some time after completion of training. Cortisol and adrenaline are necessary substances during exertion and intensive resistance training. It is counterproductive to inhibit these substances during training. The effects of these substances provide the signal for muscle growth and strength enhancement.
The active phase of training is highly catabolic. During this time, glycogen stores are quickly depleted and the liver must synthesized glucose. It performs this function by converting the amino acid L-Alanine to . This amino acid along with glutamine account for more than 50% of the total amino acid released from muscle tissue. In skeletal muscle, 60% of the free amino acid pool is glutamine.
Glutamine release is from free glutamine stores within the muscle and from deamination (removal of ammonia molecule) of branched-chain amino acids. This release of skeletal muscleglutamine may be the signal that inhibits protein synthesis in skeletal muscle models during stress.
Providing glutamine and branched-chain amino acids may' affect the signal responsible for decreasing protein synthesis. Despite the fact that the catabolic process is similar in critical illness and in weight training; there are fundamental differences. This difference defines the amino acid profile that would best suit each situation. In weight training, the major organ system involved is the skeletal muscles.
Repair and re-growth during recovery require amino acids in proportions present in the tissue affected most by the catabolic process. Glutamine and branched-chain amino acids are the logical choice. Following ingestion of a protein-rich meal, the intestines release a large quantity of amino acids, predominantly the branched-chain amino acids.
They account for greater than 60% of the total amino acids entering the body circulation, even though they make up only 20% of the total amino acids in a lean protein meal. Amino acid uptake by muscle tissue in the first hour following a meal consists of at least 50% branched-chain amino acids.
The branched-chain amino acids also serve as a donor of nitrogen in the formation of L-Alanine which provides the body with glucose after glycogen stores have been depleted.
Supplementation with both glutamine and branched-chain amino acids during periods of intense training and muscle stress may preserve better nitrogen balance and hasten recovery during and after weight training.
Weight Training and Illness
What Does Weight Training and Critical Illness Have in Common? - by Joseph Rossi MD
Both create excessive metabolic demands on the body. Both promote negative nitrogen balance. Both require optimum nutrition for the best chance of survival. In critically ill patients, the metabolic demands can increase 200% to 300%. This includes both caloric and protein requirements.
Simply supplementing calories in this setting results in negative nitrogen balance, muscle wasting, poor wound healing and overall poor outcome. During periods of critical illness and stress; the body functions in an environment of counter-regulatory hormone excess including cortisol, adrenaline and glucagon.
These hormones are necessary for survival; however, they are catabolic and create high levels of negative nitrogen balance.
Protein excretion is increased in severe illness. In trauma patients and those with severe body burns, it can reach 250 g/day. The major role of increased rates of protein degradation during metabolic stress is to provide amino acids, especially branched-chain amino acids which donate nitrogen for the synthesis of glutamine.
This glutamine, after release by the muscle, is essential for functioning of the immune system amino acids during periods of injury and stress is skeletal muscle. Under metabolic stress the muscle and plasma concentrations of glutamine decrease. it has been shown that there is a correlation between the concentration of glutamine and the rate of protein synthesis. The overall result is skeletal muscle breakdown to provide metabolic control during periods of high stress.
Also, it helps to explain why there is such a large increase in protein degradation in skeletal muscle during injury and stress and indicates that it is essential for the survival of the body under normal conditions. This is a similar situation to that found for the effects of physical training on skeletal muscle.
Several studies have indicated that the use of branched-chain amino acids improve nitrogen balance during injury and stress. This is also suggested for glutamine. By directly supplementing glutamine and branched-chain amino acids, the signal for skeletal muscle breakdown may be inhibited.
Also, branched-chain amino acids and glutamine may directly stimulate muscle protein synthesis. Improved nitrogen balance has been reported in bone marrow transplant patients, burn patients, and those undergoing major surgery.
In addition, glutamine has been shown to increase both growth hormone and insulin levels. Heavy resistance training creates a similar environment to that of the critically ill patient. High levels of cortisol and adrenaline released during training inhibit protein synthesis and create negative nitrogen balance.
These effects can persist for some time after completion of training. Cortisol and adrenaline are necessary substances during exertion and intensive resistance training. It is counterproductive to inhibit these substances during training. The effects of these substances provide the signal for muscle growth and strength enhancement.
The active phase of training is highly catabolic. During this time, glycogen stores are quickly depleted and the liver must synthesized glucose. It performs this function by converting the amino acid L-Alanine to . This amino acid along with glutamine account for more than 50% of the total amino acid released from muscle tissue. In skeletal muscle, 60% of the free amino acid pool is glutamine.
Glutamine release is from free glutamine stores within the muscle and from deamination (removal of ammonia molecule) of branched-chain amino acids. This release of skeletal muscleglutamine may be the signal that inhibits protein synthesis in skeletal muscle models during stress.
Providing glutamine and branched-chain amino acids may' affect the signal responsible for decreasing protein synthesis. Despite the fact that the catabolic process is similar in critical illness and in weight training; there are fundamental differences. This difference defines the amino acid profile that would best suit each situation. In weight training, the major organ system involved is the skeletal muscles.
Repair and re-growth during recovery require amino acids in proportions present in the tissue affected most by the catabolic process. Glutamine and branched-chain amino acids are the logical choice. Following ingestion of a protein-rich meal, the intestines release a large quantity of amino acids, predominantly the branched-chain amino acids.
They account for greater than 60% of the total amino acids entering the body circulation, even though they make up only 20% of the total amino acids in a lean protein meal. Amino acid uptake by muscle tissue in the first hour following a meal consists of at least 50% branched-chain amino acids.
The branched-chain amino acids also serve as a donor of nitrogen in the formation of L-Alanine which provides the body with glucose after glycogen stores have been depleted.
Supplementation with both glutamine and branched-chain amino acids during periods of intense training and muscle stress may preserve better nitrogen balance and hasten recovery during and after weight training.
