Cortisol Levels and Muscle Building
What is Cortisol?
- Cortisol is a glucocorticoid, which is also called hydrocortisone.
- Cortisol is produced in the adrenal cortex and is produced and released in response to physical, mental and emotional stress.
- Cortisol is also produced in alignment with our natural circadian rhythm.
- Made from cholesterol, cortisolâ€™s synthesis and release are controlled by adrenocorticotropic hormone (ACTH).
- Cortisol is known to be the most catabolic hormone in your body.
Cortisol is a hormone that gets produced by cholesterol.
Cholesterol certainly isnâ€™t as bad as one first thought. In fact, cholesterol is vital within the body. Every cell residing inside the body needs cholesterol, and ALL steroid hormones get synthesised from cholesterol, including sex hormones and the adrenal hormones.
Cortisol Levels â€“ Peak early morning
Cortisol finds itself aligned with the circadian rhythm or sleep cycle we are governed by as humans. In the morning, cortisol rises to wake us out of sleep and get a move on with the day. Cortisol peaks around 8:00 am, wearing off to its lowest levels at 3-4am.
As a stress response, the body must preserve energy so that we are equipped to deal with the danger it has detected. Naturally, messages start to get sent out to areas of the body that are not critical at this time. Reproduction is one such area; the body deems unnecessary in a stressful situation. This shutdown results in a dramatic decrease in testosterone in males. Since testosterone is a vital growth factor determining muscle growth, halting its productivity provides adverse outcomes.
Cortisol and Glucose Metabolism
New glucose production is called gluconeogenesis. Cortisol stimulates gluconeogenesis in the liver. It uses amino acids, glycerol, lactate, and propionate. Cortisol also has involvement in glycogenolysis which is the breakdown of glycogen stored in the liver and muscle cells. Glycogenesis is a necessary function which activates glycogen phosphorylase, an enzyme needed to complete the entire process.
Cortisol also stops insulin from transporting glucose into cells by decreasing the translocation of glucose transporters to the cell surface.
Cortisol and its relationship to bones and muscle
CortisolÂ prevents bone formation and minimises calcium absorption within the intestine. Bone and muscle growth is halted when cortisol levels are high.
1. The Institute of Functional Medicine, Textbook of Functional Medicine, (Gig Harbor, WA: 2010).