You’ve heard about the many wonderful benefits of mindfulness meditation practice, perhaps you’ve even experienced some of them yourself – but do you really know how it works? What happens in our bodies, and brains, when we practice?
There’s the obvious: if you stop, take a few slow breaths, and just observe what’s happening around you, it makes sense that your breathing may get deeper, your heart rate may slow down, and you may feel calmer and more relaxed. It’s easy to imagine that you might be less stressed and less reactive if you were to do that on a daily basis.
But can sitting and focusing on your breath keep you from getting the flu, or relieve your psoriasis, or prevent your depression from returning? Can practicing mindfulness meditation actually cause physical changes in how your immune system and nervous system function? The answer is clearly yes to all of these questions, as recent scientific research has demonstrated.
First, let’s review our basic anatomy: the autonomic nervous system (ANS) has two branches, sympathetic (SNS) and parasympathetic (PNS). The SNS governs movement of the large muscles of the body – it’s what gets engaged when we go into “fight or flight” mode. The PNS acts as the brake to the SNS’s accelerator, regulating digestion and the relaxation response, so we refer to it the “rest and digest” system. When we’re stressed and anxious, the SNS is in overdrive; the PNS is dominant in the “relaxation response,” which we get from meditation.
The diaphragm is a band of muscle that encircles the torso just below the ribcage. When we breathe deeply we engage the diaphragm: it expands as we inhale and contracts as we exhale. Breathing from the diaphragm activates the PNS, via the vagus nerve.
The vagus nerve “wanders” from the brain stem down into the torso, with branches that lead to internal organs, including heart, lungs, stomach, kidneys, spleen, liver, and intestines. The vagus nerve relays messages from the body back to the brain (80% of its fibers run in this direction).
The stronger the activity of the vagus nerve, the greater heart rate variability (HRV). That’s a good thing, because low HRV is associated with heart disease. Biofeedback has been used experimentally to help heart patients increase their HRV. Not only did participants in clinical trials lower their blood pressure, they also experienced relief from pain, anxiety, and depression.
In HRV biofeedback, you learn to make your heart rate move into a sine wave, called “resonance.” It is thought that this strengthens the heart muscle, and makes it more elastic, thereby resilient. But it wasn’t clear why it would also affect mental health, until researchers looked at the role of the vagus nerve – remember, it sends signals to the brain from the body, and it regulates the PNS.
According to the research, people with high HRV have more flexible and adaptive emotional responses to stress, tend to have more working memory, can focus their attention better, and are better able to regulate their own emotions. Guess what? These are the very same benefits reported for Mindfulness-based Stress Reduction (MBSR) and other forms of mindfulness meditation. What’s the connection? The vagus nerve, which is stimulated by deep, slow, diaphragmatic breathing.
HRV is often used as a measure of vagal tone, and an indicator of how active the parasympathetic nervous system is. It turns out we can increase vagal tone by changing our thoughts. Several studies have shown that vagal tone increased when participants focused on positive emotions, or practiced loving-kindness meditation. Other research points to the role of social connection in stimulating the vagus nerve. We know from previous research that both changing negative thoughts as well as strengthening social bonds lead to increased stress resilience – again, the vagus nerve at work!
Research has also found that the vagus nerve can act as a powerful brake on inflammation. Vagal nerve stimulation (VNS) is being used experimentally to treat patients with rheumatoid arthritis and Crohn’s disease. In principle, it could work for other disorders that involve inflammation, which is an immune system response to an injury (muscle sprain, bone break) or intruder (bacteria or virus). VNS also shows promise for psychiatric conditions – and we’re learning that inflammation may play a role in these disorders as well.
The treatments I’ve mentioned are still in the experimental stage, but what is available to all of us right now is the ability to regulate our own vagus nerve, via mindfulness meditation practice!
Image by Arek Socha from Pixabay