The Hidden Brain-Gut Link and How it Helps Manage Stress

Everyone is familiar with the uncomfortable feeling of a racing heart and sweaty palms in anticipation of a threat, whether that’s public speaking, financial concerns, or encountering an unfamiliar situation. This is known as the “fight or flight” response and is activated by our nervous system. However, many modern-day stressors cannot be outrun or fought off, which begs the question: How can we handle stress in our daily lives? The answer might lie within the connection between our gut and our brain.

The Nervous System

It is first important to understand how our body’s nervous system works in order to combat stress that can frequently overburden it. Here are some of its key components:

Central Nervous System (CNS): Consists of the brain and spinal cord.
Sympathetic nervous system: Activates the “fight or flight” response by increasing the heart rate, dilating pupils, and reducing gut activity.
Parasympathetic nervous system: “Rest and digest.” This acts in direct opposition to the sympathetic system by reducing heart rate, constricting pupils, and increasing gut motility.
Enteric Nervous System (ENS): The ENS is the gastrointestinal tract’s own nervous system. It regulates gut hormone release, gut motility, and interacts with the immune system.

The Gut-Brain Axis

The nervous system and the gastrointestinal tract are both closely intertwined in maintaining homeostasis within the body. This is referred to as the gut-brain axis and is made up of the CNS and ENS, as well as the HPA (hypothalamus-pituitary-adrenal)-axis. Together, the body’s gut and brain send and receive signals along this axis that inform each system of how the body is functioning and reacting to stimuli in its environment.

Functions of the Vagus Nerve

The vagus nerve is the tenth cranial nerve and is the main component of the parasympathetic nervous system, playing a large role in regulating relaxation in the body. It travels down the left and right sides of the body from the brain to the abdomen. Importantly, it serves as a “middle-man” between the brain and the gut, relaying signals between both systems within the gut-brain axis while regulating involuntary functions such as respiration, heart rate, and digestion.

Role of the Gut

The nervous system–and its various parts–is partnered with the digestive system, but why is this important? Researchers have determined that intestinal flora is linked to mental disorders such as depression, anxiety, and increased stress which can lead to a lower quality of life. Similar to neurotransmitter imbalances within the brain that can result in mental illness, an unbalanced gut microbiome has significant effects on your mental health.

Combatting Stress

As the main link between our brain and our gut, the vagus nerve aids in balancing these systems on its own, but there are ways to promote decreased stress within the body by paying closer attention to this nerve.

Vagus nerve stimulation

VNS is a traditionally invasive surgery in which a stimulator is implanted in the chest and sends electrical impulses to the vagus nerve. These impulses are transmitted to the brain and are shown to have an impact in treating mental conditions such as depression and anxiety, as well as inflammatory bowel disease (IBD). More recent technologies have also made it possible to receive VNS through non-invasive devices.

Alternative stimulation methods

You can stimulate the vagus nerve without an electrical device, such as through specific exercises. Vocal cord stimulation works to activate the vagus nerve, which can look like deep breathing techniques, singing/humming, or gargling water. While the impacts of these exercises may not be as significant as VNS, you may experience relief without the necessity of implanting a device.

Additional stress-relief techniques

Though not specific to the vagus nerve or the gut, it is important to consider the body as a whole and maintain healthy habits that promote homeostasis in order to reduce stress. This can look like exercising regularly, eating a balanced diet, and surrounding yourself with a supportive social network, all of which can serve as a buffer against unexpected stress and anxiety.

With a better understanding of how our nervous system operates in conjunction with our digestive system, we can manage daily stressors and reduce their negative impacts on our overall health. A daily reminder to set aside time for relaxation and to tune in to our nervous system can ultimately generate positive outcomes in managing stress and anxiety.