The Vagus Nerve
Within the realm of functional medicine & mental health, the term ‘vagus nerve’ is one we hear often, yet rightfully so. The vagal nerves in our body are the key component in activating our parasympathetic nervous system. The vagus nerve is one of twelve cranial nerves in the body, running from the brain to the abdomen, and is responsible for the regulation of our internal functions including our digestion, a healthy heart & respiratory rate, & our immune system.
In conjunction with its pivotal role in our parasympathetic nervous system, the vagus nerve also serves as key modulator within the gut-brain axis (GBA). The gut-brain connection consists of bidirectional communication between our central & enteric nervous systems, linking emotional & cognitive centers of the brain with peripheral intestinal functions. The vagus nerve can be activated by the microbiota of our gut, transmitting information from the gastrointestinal tract to the nucleus tracts solitarius (NTS). The NTS further transmits information into our central autonomic network through a plethora of neural pathways. This “brain in your gut” works directly with the vagus nerve to send messages to your brain ( & vice versa), as well as regulate the internal functions listed above.
When our vagus nerve is deactivated, we can experience a range of symptoms. These could include poor digestion (IBS, SIBO, etc.), chronic inflammation, low immunity, sensory difficulties, and weakened liver detoxification, among other symptoms. However, when the vagus nerve is activated, our digestion and sleep is at it’s optimal state, our immune system has proper function, the inflammation in our bodies is decreased, & we’ll experience overall lower levels of stress & anxiety.
While the internal functions the vagus nerve regulates are involuntary, meaning we do not conscious control over them, the vagus nerve in our body can be stimulated. In doing so, we can send a message to our brain to lower our levels of stress & relax our bodies. Below, I have curated a list of my favorite (and most effective) ways to stimulate the vagus nerve & improve our overall health.
Cold Temperatures
Cold exposure is one of the best ways to stimulate the vagus nerve, especially a cold plunge. Cold exposure via an ice bath or cold shower activates the vagus nerve, creating a relaxing effect in the body. This is because while our body adjusts to the cold water or air, our sympathetic activity declines, while our parasympathetic activity simultaneously increases.
Deep Belly Breaths
In this form of deep breathing, the diaphragm contracts on the inhale and relaxes on the exhale. This kind of breath work stimulates the vagus nerve, lowering our heart rates & activating the relaxation response of the parasympathetic nervous system.
Singing, Humming, Chanting, & Gargling
The vagus nerve is connected to our vocal cords, and so singing, humming, chanting, & gargling can activate these muscles in the back of our throat. The vibrations from such activities stimulate the vagus nerve, sending out neurotransmitters & electrical signals that reduce activity to key areas in our brain, such as the amygdala, which is responsible for our fight, flight, or freeze response. In using our vocal cords and activating the vagus nerve, our parasympathetic nervous system begins to take effect, lowering levels of stress and anxiety.
Interval & Endurance Training
While our sympathetic nervous system is active during exercise, recent studies have found that our parasympathetic nervous system is as well. In interval training and endurance training, the cardiac vagal nerve releases multiple mediators that help regulate our heart rate variability, and in some cases can actually increase during exercise.
Massages
During a massage, a variety of different pressure points throughout our body can be used to stimulate the vagus nerve, activating the parasympathetic nervous system. Reflexology massages in particular can increase vagal tone, decreasing blood pressure levels in our bodies, as well as lowering levels of stress & anxiety.
