Cortisol is a hormone involved in a wide range of bodily processes such as immune response, metabolic function, and blood pressure. Adrenaline, also known as epinephrine, is also a stress hormone. However, cortisol and adrenaline are two distinct stress hormones that act in completely different ways.
Before understanding how cortisol interacts in stressful situations, let's break it down.
The release of cortisol is controlled by the Hypothalamus, the pituitary gland, and the adrenal glands. This is also known as the HPA axis (hypothalamic-pituitary-adrenal axis). Whether the body perceives a psychological or physical stressor, the HPA axis releases cortisol in the following order:
It is critical to note that each step stimulates the step that follows. Ultimately, the adrenal glands (present above each kidney) produce the hormone cortisol, but it is the hypothalamus and pituitary glands that trigger this process.
So how is cortisol relevant to the body’s ‘fight or flight response?’
When the body perceives a stressor, the brain activates the sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA) axis. The sympathetic nervous system is responsible for involuntary bodily functions such as the ‘fight or flight response.’ The HPA axis is involved in regulating this stress response.
The cortisol that is released by the HPA axis supports the body’s reaction to stress. How? Cortisol elevates the body’s blood sugar levels by releasing stored glucose, which increases one’s energy. Additionally, when cortisol increases, the body suppresses non-essential functions for the time being. This includes functions such as digestion and immune response. Thus, the increase in cortisol levels supports immediate survival techniques in stressful situations.
FYI, a ‘stress’ hormone does not only occur in situations where you feel stressed out; instead, it’s when your body is put under stress. This could be heavy breathing, a fight with a friend, a hard workout, etc. So, in all of these situations, your cortisol levels will be high. Our body cannot differentiate between an intentional stressor and an unintentional stressor- like a routine freezing cold morning shower versus a bad argument with a friend. Cortisol will be produced either way.
So if cortisol is produced when our body is under stress, when else is it produced, and when is it not produced? Let’s get some facts down: cortisol levels are highest in the morning and lowest at night. Also, cortisol levels are heightened during intense physical activity (to mobilize energy stores). Cortisol can also be increased due to food- high-glycemic carbohydrates can temporarily increase cortisol levels.
Overall, the body will increase or decrease levels of cortisol many times during the day. Here’s what you need to know: Cortisol is essential for your body to function by regulating your body's stress response and helping control the body's use of fats, proteins, carbohydrates, and your metabolism. However, your cortisol levels should not rest at an elevated state, which would typically occur if you're dealing with chronic stress - this can be very dangerous. Measuring cortisol levels can be done through blood tests, saliva tests, or urine tests.