Essential for life, cortisol exerts a wide range of effects that effects a number of the body's organ systems. The steroid hormone, produced in the adrenal cortex, helps you deal with stressful situations, plays a part in the breakdown of stored fat and coordinates the sleep-wake cycle. When cortisol levels remain raised for too long, as occurs during times of stress, negative changes in your metabolism may occur.
Cortisol
Robert Kapolsky PhD, a researcher and the author of the best-selling book on stress "Why Zebras Don't Get Ulcers," explains how cortisol works in unison with another stress hormone, adrenaline. Whereas adrenaline makes you ready for fight-or-flight situations by increasing the activity levels of the immune system and flooding the bloodstream with sugars and free fatty acids, cortisol compensates for these fluctuations and helps maintain long-term balance.
Insulin Resistance
Cortisol helps maintain the balance by inducing selective insulin resistance. This insulin resistance is selective in the sense it only affects muscles that have not recently worked. In evolutionary terms, this provides a distinct benefit as allows the worked muscles to replenish their energy stores quicker and without competition from those that have done nothing. Problems occur when stressful situations occur in non-physical settings, such as behind a desk or in the car, and insulin resistance occurs across the entire body. Kapolsky links insulin resistance with increased cardiovascular risk and increased fat storage.
Fat Burning
As well as the changes in insulin resistance, cortisol may affect the rate of fat burning in a more direct manner. Kapolsky explains that the body regulates fat burning through the balance of fat burning enzymes against those that store fat. Those that store fat, known as lipogenic enzymes, contain receptors for cortisol; excessive release of the steroid hormone results in increased activity of these enzymes and can lead to weight gain.
Sleep
Cortisol also plays a major part in your sleep-wake cycle, rising in early morning to help wake you up and dropping in the evening to facilitate a restful nights snooze. Charles Poliquin, the Canadian strength coach who has worked with 16 Olympic medal-winning athletes, explains that excessive cortisol release can often make his athletes feel too wired to sleep in the evening.
Expert Insight
Poliquin makes a number of suggestions to counter excessive rises in cortisol release. He finds that reishi mushroom extracts, phosphatidyl-choline and magnesium taurate all effectively lower production of the stress hormone, while stretching before bed and avoiding violent TV shows in the evening can also make a significant difference.
References
- "Why Zebras Don't Get Ulcers;" Dr. Robert Kapolsky; 2002
- Charles Poliquin: Are You Too Nervous to Grow?
Member Comments