Hi friends, welcome to chat with me about the vagus nerve. This nerve is like a highway in our body, transmitting information packets back and forth. It carries commands from the brain to organs like the heart, stomach, lungs, and intestines, while also feeding back sensations and states from these organs to the brain. The vagus nerve is called the \"wandering nerve\" because it starts from the brainstem, passes through the neck and chest, and extends all the way to the abdomen, sending \"relax, repair, and rest\" parasympathetic signals to many important organs along the way.
What's more interesting is that 80% of the vagus nerve's activity is receiving information: in other words, our understanding of the body mainly depends on the \"reports\" this nerve feeds back to the brain. Imagine what would happen if the vagus nerve were cut off. The brain would be like a boss who can't see how employees are working, forced to guess. As a result, we would feel anxious, have a racing heart, stomach discomfort, and cold hands and feet—because the brain hasn't received the \"it's safe now\" information and remains in a state of alertness. What we really want is the opposite: to send the brain a signal that \"everything's fine, time to sleep,\" making the body feel safe so the brain can confidently press the sleep button. Besides serving as an information channel, the vagus nerve also plays an important role in the parasympathetic nervous system. You know, the sympathetic nervous system prompts you to \"fight or flight,\" like when your heart races when facing danger. The parasympathetic nervous system is like a brake, making you slow down and relax, like relaxing on the couch. The vagus nerve is the \"VIP\" gateway of the parasympathetic system: it can slow your heart rate, slow your breathing, activate your gastrointestinal system, make you feel safe, and even make you more likely to smile and socialize. When the vagus nerve is active, we find it easier to transition from a tense state to a relaxed state.
Scientists often use heart rate variability (HRV) to measure vagus nerve activity. The higher the HRV, the more flexible the heartbeat, and the easier it is for the body to switch between tension and relaxation. The vagus nerve controls most of the HRV. Therefore, if you often feel anxious, have a racing heart, and shallow breathing, your vagus nerve activity is likely low. Low HRV makes it difficult to truly relax at night. However, if you \"touch\" the vagus nerve through techniques like deep breathing, applying ice to the neck, humming softly, or yawning, your HRV will increase, making it easier for your body to enter rest mode. Another interesting finding, the polyvagal theory, suggests that the vagus nerve is actually divided into two parts: the ventral vagus nerve, which makes us feel safe, friendly, and happy; and the dorsal vagus nerve, which is older and causes us to feel \"frozen,\" \"numb,\" and \"exhausted.\" For example, when a person becomes stiff and expressionless when nervous, this is actually the dorsal vagus nerve being activated. What we want is for the \"safe and social\" part of the vagus nerve to be activated during sleep, not the \"freeze system.\" Learning to activate the right part of the vagus nerve is the starting point for improving sleep.
Chapter Summary:
• The vagus nerve is the highway connecting the brain and various internal organs.
• It is responsible for sending relaxation signals throughout the body.
• Higher heart rate variability (HRV) indicates active vagus nerve activity, making it easier to fall asleep.
• Polyvagal theory reminds us that being quiet is not always better; instead, activating the \"safe and active\" part is also important.
Today's Practical Tips:
• Practice deep breathing: Inhale for 4 seconds, hold for 2 seconds, exhale for 6 seconds. Practice for 3 minutes daily to help improve heart rate variability.
• In the afternoon or evening, wrap an ice pack in a towel and apply it to both sides of the neck for three minutes to quickly \"awaken\" the vagus nerve through cold stimulation.
• Sit in a quiet place and hum a favorite melody softly for five minutes. The sound doesn't need to be loud, but should have low-frequency resonance, which can directly soothe the vagus nerve branches hidden near the ear.
In the next chapter, we will delve into the concept of neural regulation, exploring how the body automatically switches between \"tension\" and \"relaxation,\" and how to make the vagus nerve more flexible through daily training to more effectively help us fall asleep at night.