Stress and cortisol

Stress is a normal part of everyday life. Some stress is good for us, some stress can be harmful. But chronic, long-term stress has been called toxic stress because it can lead to self-destructive eating behaviours. Toxic stress puts fat on and can lead to disease. 

When a threatening event takes place, our bodies are purpose-built to act on that event. Our entire being from tissues, blood cells, brain chemicals and hormones pump messages to our heart, lungs, and limbs. Our stress response was designed to protect us from danger. However, we live in a much less dangerous world than our ancestors did. As we became less physical, we got smarter. We substituted intellectual stresses for physical ones. But our bodies are still wired for some sort of physical response. Fight or flight.

Our bodies are built to move, to balance thought and action. So when we don’t have a physical release, stress accumulates and may become toxic.

Here’s what happens: when the brain first registers a stressful event, it releases a chemical known as corticotropin-releasing hormone (CRH); it raises the alarm. There is a baseline of this hormone in our body, and it can be elevated by anything that stimulates your senses: fear, excitement, passion, panic, anxiety, happiness, or joy. Once the alarm is triggered, a cascade of neurochemical sparks, designed to prepare the body for fight or flight, kicks in.

The alarm hormone also activates the adrenals, two glands located in the abdomen, and tells them to secrete two substances: adrenaline and cortisol. Cortisol is known in the scientific literature as glucocorticoid, because of its ability to stimulate glucose elevations in the blood and because it is secreted by the outer part of the adrenal gland called the cortex.

CRH (the alarm hormone), cortisol and adrenaline follow a distinct rhythm of secretion throughout the day. These stress hormones tend to peak between 6 and 8 a.m. and begin a gradual decline later in the morning reaching their lowest levels at night. By about 2 a.m., the levels begin to rise again, preparing you for the morning to help you cope with the next day’s stresses.

The body reacts to a stressful event within seconds of it happening. The body goes into code red: pupils dilate, blood pressure rises, thinking and memory improve, and lungs take in more oxygen. Digestion is put on hold, allowing the body to concentrate its energy on the muscles needed for the physical stress response. Immune function is momentarily suppressed for the same reason. Physical sensation of pain is dulled to minimize distraction and focus more attention on the coping mechanism. All systems are on high alert.

In addition to these physical responses, the alarm hormone activates the reward and pain relief areas of the brain. Most physiological functions in the human body involve stressing the body’s systems in a healthy way. This includes digestion and metabolism. This concept of reward helps to explain what can go right as well as what can go wrong in some people’s eating patterns under stress.

The fight or flight response is ideal for situations that require you to defend yourself or cope with daily stresses that require physical strength and endurance.  This response is designed to get you moving away from danger. Cortisol grabs high-octane fat and energy-propelling glucose from the body’s stores, diverts blood away from internal organs, and directs them to your brain, heart, lungs, and muscles for immediate energy.

Once the immediate “danger” is over the adrenaline level in the bloodstream rapidly decreases. Cortisol, on the other hand, lingers in the system and is designed to help bring the body back into a balanced state. The behavioral and physical adaptations to stress reverse, and the body returns to its normal state.

But what if one is under chronic stress? You can clearly see how this could lead to disease because the body will keep secreting stress hormones until a critical threshold is reached. When that happens, the body, being constantly primed for action, is bathed in waves of these hormones and it never gets a chance to return to homeostatis (balance). And this is when health begins to break down.