How do adrenal hormones like cortisol affect metabolism?

Adrenal hormones like cortisol stimulate metabolism by increasing blood sugar levels and suppressing the immune system.

Cortisol, often referred to as the 'stress hormone', is produced by the adrenal glands, which are small glands located on top of each kidney. This hormone plays a crucial role in the body's response to stress, but it also has a significant impact on our metabolism, the process by which our bodies convert food into energy.

Cortisol influences metabolism by increasing the levels of glucose (sugar) in the bloodstream. This is achieved through a process called gluconeogenesis, where the liver converts non-carbohydrate substances like amino acids and lipids into glucose. This surge in blood sugar provides the body with a quick energy source, preparing it to respond to stressful situations. This is part of the 'fight or flight' response, a physiological reaction that occurs in response to a perceived harmful event or threat to survival.

In addition to increasing blood sugar, cortisol also suppresses the immune system. This is because the immune response is energy-intensive, and during times of stress, the body prioritises functions that are critical for immediate survival. By suppressing the immune system, cortisol ensures that energy is conserved and available for vital functions like heart rate and muscle action.

Furthermore, cortisol promotes the breakdown of fats and proteins within the body. This process, known as catabolism, releases energy and provides the necessary substrates for gluconeogenesis. This further contributes to the increase in blood sugar levels and the availability of energy.

However, prolonged exposure to high levels of cortisol can lead to various health problems. These include weight gain, high blood pressure, and type 2 diabetes. This is because the body continues to produce glucose, leading to an excess of sugar in the blood. Over time, this can cause insulin resistance, a condition where the body's cells become less responsive to insulin, a hormone that regulates blood sugar levels.

In summary, adrenal hormones like cortisol play a vital role in metabolism by increasing blood sugar levels, suppressing the immune system, and promoting the breakdown of fats and proteins. However, it's important to note that while these processes are beneficial in the short term, long-term exposure to high cortisol levels can lead to serious health issues.