How Cortisol Breaks Down Muscle
Understanding cortisol's catabolic activity in muscle provides some insight into the way certain food supplements may help spare muscle by inhibiting it. Cortisol is known to reduce body protein stores in all tissues except for the liver. It does that through several mechanisms, including a reduction in the synthesis of cellular RNA, which is essential for protein synthesis. Since anabolic steroids promote muscle protein synthesis by increasing RNA, cortisol has exactly the opposite effect.
Cortisol mobilizes amino acids from muscle for transport to the liver, where they undergo a process called gluconeogenesis that results in increased glucose production. While this is vital for a rapid source of energy during severe stress, it also results in muscle breakdown. Insulin opposes cortisol in the action, but high stress activity promotes cortisol domination over insulin.
Recent studies show that consuming carbohydrates and protein immediately following a workout both increases insulin release and potently blunts cortisol. The dosage of carbs required for this effect is one gram per kilogram (2.2 pounds) of bodyweight taken immediately after training and again one hour later. In addition, including at least 50 grams of protein helps maximize insulin release.
Cortisol appears to promote the synthesis of a protein-degrading substance called ubiquitin that rapidly breaks down muscle. Interestingly, a drug called clenbuterol that's favored by some bodybuilders may work by inhibiting ubiquitin synthesis in muscle, thereby exerting an anticatabolic effect. Other hormones, such as growth hormone and insulinlike growth factor 1 (IGF-1), appear to inhibit the ubiquitin system as well.
Cortisol also works by stimulating the exit of the amino acid glutamine from muscle. When that occurs, rapid muscle catabolism follows. Several studies show that taking supplemental glutamine may block much of the catabolic effects of cortisol in muscle.
A study conducted about two years ago showed that as little as two grams of oral glutamine significantly increased growth hormone release. That alone would give you an anticatabolic effect, since growth hormone opposes the actions of cortisol in muscle. In fact, studies indicate that decreasing cortisol release in the body results in an upgraded growth hormone response.
Understanding cortisol's catabolic activity in muscle provides some insight into the way certain food supplements may help spare muscle by inhibiting it. Cortisol is known to reduce body protein stores in all tissues except for the liver. It does that through several mechanisms, including a reduction in the synthesis of cellular RNA, which is essential for protein synthesis. Since anabolic steroids promote muscle protein synthesis by increasing RNA, cortisol has exactly the opposite effect.
Cortisol mobilizes amino acids from muscle for transport to the liver, where they undergo a process called gluconeogenesis that results in increased glucose production. While this is vital for a rapid source of energy during severe stress, it also results in muscle breakdown. Insulin opposes cortisol in the action, but high stress activity promotes cortisol domination over insulin.
Recent studies show that consuming carbohydrates and protein immediately following a workout both increases insulin release and potently blunts cortisol. The dosage of carbs required for this effect is one gram per kilogram (2.2 pounds) of bodyweight taken immediately after training and again one hour later. In addition, including at least 50 grams of protein helps maximize insulin release.
Cortisol appears to promote the synthesis of a protein-degrading substance called ubiquitin that rapidly breaks down muscle. Interestingly, a drug called clenbuterol that's favored by some bodybuilders may work by inhibiting ubiquitin synthesis in muscle, thereby exerting an anticatabolic effect. Other hormones, such as growth hormone and insulinlike growth factor 1 (IGF-1), appear to inhibit the ubiquitin system as well.
Cortisol also works by stimulating the exit of the amino acid glutamine from muscle. When that occurs, rapid muscle catabolism follows. Several studies show that taking supplemental glutamine may block much of the catabolic effects of cortisol in muscle.
A study conducted about two years ago showed that as little as two grams of oral glutamine significantly increased growth hormone release. That alone would give you an anticatabolic effect, since growth hormone opposes the actions of cortisol in muscle. In fact, studies indicate that decreasing cortisol release in the body results in an upgraded growth hormone response.
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