What happens in your body when you’re stressed
You know what stress feels like. But what actually goes on in your nervous system, and how can it help you?
What is stress, really?
While we tend to correlate “stress” with feelings of overwhelm and fear, stress in the biological sense is not exactly this. From an evolutionary standpoint, “stressful” situations, such as being attacked by a predator, trigger an organism’s fight or flight response, allowing for a rapid and reflexive reaction to danger or a stimulus. Stress is simply your body’s overall response to any challenge, short-term or long term, and is great for you more often than not.
There are two major kinds of stress: eustress and distress.
Eustress is typically considered to be beneficial and is very normal and temporary. It’s the kind of stress that results from everyday situations, such as conflicts or solving a tough math problem.
Distress comes in two forms — acute and chronic. Acute distress happens as a result of short term situations that aren’t as commonplace as eustress triggers. Examples of acute distress triggers include grief and breakups. Chronic stress is caused by long-term situations such as childhood abuse, depression, trauma, and addiction.
How stress begins
The hypothalamus is responsible for your response to stress. The hypothalamus is a small region near the center of your brain that links your nervous system with your endocrine (hormone) system. When a stressor is identified by your nervous system, your hypothalamus releases corticotrophin to your pituitary gland (a pea-sized part of the brain responsible for monitoring hormone releases). In other words, your hypothalamus reacts to a stressor by signaling to your pituitary gland to release a hormone.
Your pituitary gland releases the adrenocorticotropic hormone, or ACTH. It’s a mouthful, but it’s only so long because it includes root words that describe it’s function. Let’s break it down:
- “adreno” refers to the adrenal glands, which are responsible for releasing a very important stress hormone which we will discuss later. They look like little pyramids on top of your kidneys.
- “cortico” refers to the cortices of the adrenal glands, which are simply their outer layers. These are the specific parts of the adrenal glands that secrete cortisol.
- “tropic” comes from Greek suffix “tropos” meaning “to turn.” This just means that the ACTH hormone causes the adrenal cortices to “turn,” or rather do something (in this case, to release cortisol).
Therefore, the adrenocorticotropic hormone (ACTH) is released by the pituitary gland to stimulate the release of cortisol by the adrenal gland cortices.
And to clarify, a hormone is any chemical messenger (never bad unless it exists in excessive amounts) that is carried by your blood to your organs to instruct them to do something. That said…
What is cortisol? (And what does it do?)
Cortisol is another hormone. It is (as we discussed) released by the adrenal cortices when your pituitary gland releases ACTH, which happens as a result of a signal from the hypothalamus reacting to a stressor.
Cortisol is responsible for initiating your “fight-or-flight” response. Cortisol works with adrenaline (also released by your friends the adrenal glands) to:
- Increase your heartrate and blood pressure — this means that nutrients carried by your blood are delivered to your muscles faster than normal, allowing you to run or fight (from an evolutionary standpoint).
- Dilate your bronchioles — your bronchioles are the major pathways to your lungs, and when they dilate, there’s more room for air to pass, letting you breathe more and more easily, which delivers more oxygen to your cells.
- Inhibit your digestive system — a temporary slow-down of your digestive system to ensure that the resources going to your digestive cells are redirected to cells more important for fighting or fleeing.
- Increase glucose production — glucose is a necessary sugar used by your cells to produce energy, a vital resource for better function. During stress, your liver begins to convert more glycogen into glucose, ensuring that your body is better equipped to deal with danger.
How about electrical responses?
While your endocrine system reacts to stress with hormones and chemical processes and loops, your brain mostly works with electrical signals. The cells in your brain give off different wave frequencies depending on the level of brain activity at a given moment. On a regular, day-to-day basis, your brain gives off beta waves in casual amounts — not too much and not in all areas of your brain. In a stressed state however, your brain begins to experience beta oscillations on a much more frequent and prevalent basis.
Why does all this matter?
It is important to understand the science behind stress for a number of reasons. For one, it allows you to be aware of the benefits and detriments of stress — you no longer label it as a “bad” thing. It also enables you to take more effective measures to decrease your anxiety. Knowing, for example, that stress is a result of massive beta wave increases, you can take steps to increase alpha wave activity by doing things like meditating. Understanding the electrical and chemical processes in your body helps you to understand yourself better.
And potentially drop cool knowledge bombs.
