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The Brain & Vagal Brake

Chances are, you've heard of the "fight or flight" response It's a physiological response to stress that has been hardwired into our DNA since historic times. But how does response work, and how does it affect our mental and emotional well-being?

To understand the fight or flight response, we need to start at the beginning: the brain stem. This is the gateway between the brain and the rest of the body, and it plays a crucial role in something called neuroception. Neuroception is the process of processing sensory information to maintain homeostasis or balance within the body.

When everything is running smoothly, the brain stem sends signals to the prefrontal cortex and the ventral vagus nerve. The prefrontal cortex is responsible for executive functioning, including reasoning, problem-solving, planning, memory, and emotional regulation. The ventral vagus nerve, on the other hand, supports social engagement by activating facial muscles crucial to effectively communicating with others. It also applies the vagal brake to heart rate, which keeps the fight/flight response and anxiety at bay.

However, when stress levels rise and homeostasis is threatened, the prefrontal cortex recognizes the distress and implements coping skills to reestablish balance. But if the stress becomes overwhelming, the amygdala starts to activate the hypothalamus, pituitary gland, and adrenal glands - also known as the HPA axis. The sympathetic nervous system kicks in, with the HPA axis moving energy to the mid-spine area.

Under distress, the HPA axis and sympathetic nervous system release the stress hormone cortisol. If distress continues to build, the adrenal glands release adrenaline to intensify the stress response. This physiological response prepares the body for action, with energy shifting from executive functioning to the arms and legs.

But what happens to the vagal brake during this time? As the allostatic load builds, it weakens, and activation moves from the prefrontal cortex and ventral vagus to the mid-spine. The HPA axis and sympathetic activation prepare the person for a flight-then-fight response. If the sympathetic response does not return a neuroception of safety, the activation moves down to the gut for the shutdown or freeze response.

So, what does all of this mean for our mental and emotional well-being? When stress becomes chronic, it can build gradually, leading to distress and activating the HPA axis. This releases stress hormones that decrease cognitive functioning and make it difficult to regulate emotions effectively. Over time, this can lead to a phenomenon called allostatic load, which is the cumulative wear and tear on the body that results from chronic stress.

However, the good news is that we can take steps to manage stress and reestablish balance. Recognizing when stress is becoming overwhelming and implementing coping skills can decrease distress and activate the prefrontal cortex. This helps to reestablish homeostasis and maintain executive functioning.

Additionally, practices like deep breathing, meditation, and mindfulness can activate the vagus nerve and promote a sense of calm and relaxation. By doing so, we strengthen the vagal brake and increase heart rate variability (HRV), which correlates with an increased capacity for cognitive functioning and social engagement.

In conclusion, understanding the fight or flight response and how it affects our mental and emotional well-being can help us manage stress more effectively. By recognizing the signs of distress and implementing coping skills, we can reestablish balance and maintain executive functioning. Additionally, practices like deep breathing and meditation can activate the vagus nerve and promote a sense of calm, increasing our capacity for cognitive functioning and social engagement.

The Optimal HRV app is easy to use and offers personalized insights into stress management. It provides data visualization and real-time feedback, so users can see their progress over time and adjust their techniques accordingly. Additionally, the app offers a variety of relaxation techniques, including low and slow breathing exercises, guided meditations, and self-compassion practices, all of which have been shown to increase HRV and promote effective stress regulation.


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