We’ve all experienced nervousness, whether it manifests physically through a dry mouth, chest pains, or digestive issues, or mentally in the form of anxiety or depression. But what exactly happens in your body during these moments, and how does it relate to your brain and the stress response? Let’s explore this further.
Two components of your autonomic nervous system play a significant role in the stress response: the parasympathetic nervous system and the sympathetic nervous system. Let’s take a closer look at their functions.
These systems work together to mobilize energy when needed and facilitate relaxation afterward. The sympathetic nervous system is responsible for the fight-or-flight response, while the parasympathetic nervous system, also known as the rest-and-digest system, promotes calmness. To differentiate between the two, think of a parachute, which slows you down—a similar function to the parasympathetic nervous system.
When the sympathetic nervous system is active, you might notice an increased heart rate, a dry mouth due to inhibited salivation, and digestive issues like diarrhea or constipation. This response occurs because your body is either preparing to fight or flee from danger, which doesn’t necessitate digestion. Activation of this system releases adrenaline and stimulates glucose production to provide energy to cells and muscles. Prolonged activation leads to cortisol release, indicating an extended fight-or-flight state.
In contrast, the parasympathetic nervous system constricts pupils and restarts the digestive process, as there is no immediate danger, and it’s time to rest and digest.
Throughout a typical day, these systems are activated intermittently, maintaining balance. However, in chronically stressed individuals, the sympathetic nervous system tends to be more active than the parasympathetic nervous system, resulting in an imbalance. When these systems are balanced, the body is in a state of homeostasis, which is the desired state for those experiencing chronic stress. To achieve this, one must reactivate the parasympathetic nervous system more frequently.
Now that you understand the relationship between the brain and the nervous system, it’s time to discuss the final piece of the puzzle: the vagus nerve. Often referred to as the 10th nerve or even the queen of the parasympathetic nervous system, the vagus nerve plays a crucial role in stress response. In the next video, we’ll explore why it has earned such a distinguished title.
