Fighting Depression and Anxiety Through the Body

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Vagus nerve stimulation for mood support (Part 1 of 2)

There are many ways in which the physical body can influence the mind and mood. One very important link in the mind-body connection is the vagus nerve.

Also known as the tenth cranial nerve X (abbreviated CN X), the vagus nerve “wanders” from the brain to many different organs in the body. In fact, the name “vagus” comes from the Latin word for “wandering.”

The vagus nerve doesn’t just go to many places – it also performs many biological functions. The vagus nerve has motor (movement), sensory (registering the senses), and autonomic (fight-or-flight, or rest-and-digest) roles.

In the throat, the vagus nerve regulates functions like swallowing, breathing, and vocalizing. In the chest, it helps slow the heart rate and respiratory rate. In the abdomen, the nerve reaches the liver, spleen, stomach, and intestines, where it supports digestion via the neurotransmitter acetylcholine (ACh).

How the body can soothe the mind

The fibers of the vagus nerve don’t just run from the brain to the organs, but also from the organs to the brain. The brain-to-body (or top down) nerve fibers are known as efferent fibers; the body-to-brain (or bottom up) fibers are afferent.

80-90% of the vagus nerve fibers travel from the body up to the brain.

A whopping 80 to 90 percent of the vagus nerve fibers are afferent, meaning they travel from the body up to the brain (bottom up). In other words, our bodies – and what we do with and for them – directly influence how we think and feel.[1]

A number of practices – known as vagus nerve stimulation techniques – can be used to send messages of peace and calm up to the brain. These practices entail gently supporting the organs connected to the brain via the vagus nerve, such as the throat, lungs, and gut.[2]

Vagus nerve stimulation also increases heart rate variability (HRV). HRV refers to fluctuations in the amount of time between heartbeats. Under normal circumstances, the heart should increase or decrease its rate of contraction depending on what the body is exposed to. The heart’s ability to do this quickly and effectively as HRV, and HRV is a marker of good neurological health.[3],[4]

Simple ways to stimulate the vagus nerve and support HRV include taking slow, deep breaths; laughing; exercising; and supporting the health of the gut.

Today we will explore the role of breath, laughter, and exercise on mental health. In next week’s post we’ll dive into the role of the gut on the vagus nerve and mood.

Breath

The simplest way to stimulate the vagus nerve is by taking deep, belly breaths. Breathing stimulates the afferent vagus fibers in the lungs, which in turn sends a message up to the brain. The brain responds in kind by lowering blood pressure, increasing activity of the parasympathetic nervous system (the rest-and-digest branch of the autonomic nervous system), and increasing feelings of safety. These physical changes in turn help us breathe easier, and our breathing further reinforces the brain’s feeling of safety and calm in a virtuous feedback loop.[5]

Laughter

Laughter is also an effective way of stimulating CN X and supporting mood. By stimulating the afferent vagus fibers in the throat and chest, laughing triggers the brain to send out signals that decrease the production of the stress hormone cortisol and reduce levels of epinephrine (adrenaline).[6] These changes in turn help us feel calmer and happier, and make it easier to fall asleep at night.

In fact, a review of the therapeutic benefits of laughter concludes: “Laughter therapy is a noninvasive and non-pharmacological alternative treatment for stress and depression. Laughter therapy is effective and scientifically supported as a single or adjuvant therapy.”[7]

Exercise

Exercise is another effective and free way to stimulate the vagus nerve. Exercise has been shown to support the parasympathetic nervous system, increase HRV, decrease the adrenal gland’s stress response, and even increase the conversion of the amino acid tryptophan into the “feel happy” neurotransmitter serotonin.[8],[9],[10],[11],[12],[13]

It is no wonder, then, that exercise has been shown to effectively mitigate both anxiety and depression.

Exercise has been shown to effectively mitigate both anxiety and depression.

In a 2017 meta-analysis of six randomized, controlled trials, exercise was shown to significantly decrease anxiety symptoms,[14] and research on the effects of exercise on depression have likewise been encouraging.[15]

People with depression who regularly exercised were 50% less likely to be depressed after ten months than those who didn’t exercise. The lead study author James Blumenthal summarizes the data like this: “The more one exercised, the less likely one would see their depressive symptoms return.”[16]

Only 8% of those who continued exercising relapsed into depression, while 38% of the medication-only group relapsed.

In another study of 156 seniors diagnosed with major depression which, Blumenthal and other researchers at Duke University found that 30 minutes of brisk exercise three times a week was just as effective as pharmaceutical medication in relieving major depression. After 16 weeks, the patients who exercised has statistically significant improvement in their depression – improvement comparable to that of the patients who didn’t exercise and took antidepressant medications, as well as to those who both exercised and took meds. Those who continued to exercise during the next six months of the study were much less likely to experience a return of their depression symptoms: Only 8% of those who continued exercising relapsed into depression, while 38% of the medication-only group and 31% of the meds-plus-exercise group relapsed.[17],[18]

Curiously, another study by the same authors found that exercise alone worked better for alleviating depression symptoms than pairing exercise with the antidepressant drug sertraline. While the drug-plus-exercise group did see improvements, the patients who only exercised saw better results.[19]

When exercising for mood support, aerobic exercise seems to be the best for improving HRV, with medium to high intensity activities (like bicycling, jogging, and dancing) being better choices than low intensity activities. But higher intensity isn’t always better: overtraining with “warrior”-type exercises like CrossFit and high impact interval training (HIIT) may actually lower HRV & reduce vagal tone. Rather than “fast and furious” types of exercise, endurance activities like cross-country skiing, rowing, and jogging are likely more sustainable, less likely to result in injury, and more likely to enhance peripheral nervous system tone.[20],[21],[22]

In summary

Depression, anxiety, and other mental health conditions aren’t just “in your head.” The health of the brain and nervous system hinges on the health of the body, and the vagus nerve plays a huge part in linking the body with the mind. Through simple, free strategies like diaphragmatic breathing, laughing, and getting medium intensity exercise three times a week, it is possible to improve our mental health.

Stay tuned for my next article, in which I’ll explain how the digestive system can also play a significant role in soothing depression and anxiety, by way of vagus nerve support.

References

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