The vagus nerve: our route to a happier, healthier life?

Think positive and you will feel positive. We hear this message time and again from proponents of ‘New Age’ philosophies, and it sounds like a nice idea. You can do it anywhere, at any time and it doesn’t cost anything, so why not? Thinking ‘happy thoughts’ must surely be better than being negative, but does the concept have any basis in science, and can it actually have an impact on our physical and mental well-being? There is a scientific study being conducted at the University of North Carolina which suggests that it can and does, and they can prove it.

Apparently, the processor of positive thoughts inside our bodies is the vagus nerve, also known as the tenth cranial nerve. In Latin, ‘vagus’ means ‘wandering’, and the nerve was so named due to its meandering and multi-branched route through the body; it originates at the brain stem and travels through the chest where it spreads out in multiple directions to innervate organs in the neck, thorax and abdomen, effectively connecting your brain to your lungs, digestive tract and, most notably, your heart.

As a major player in the parasympathetic nervous system (PNS), it comes as no surprise to learn that the vagus responds to our thoughts, both positive and negative, and due to its connection to the major organs, its responses can have far-reaching effects on our physical and mental health. Scientists have found that the vagus assists the adrenal glands during ‘fight or flight’ situations by stimulating the release of epinephrine (adrenaline) in the brain. It is the vagus nerve which activates the PNS to calm the body after the perceived danger has passed, slowing the heart rate so that normal bodily functions, such as digestion, can resume. The vagus is also involved in sexual arousal and satisfaction, speech and swallowing, controlling the larynx, regulating heart rate and digestive processes, and modulating inflammation. It also relays information to the brain from what is known as the Enteric Nervous System (ENS). The ENS is known as our "second brain" and controls the digestive process; it comprises over 500 million neurons surrounding the digestive tract. It is called a second brain because it can function independently from the brain if the vagus nerve is severed.

Psychologist Barbara Fredrickson and Nancy Havill, a research associate working on the North Carolina vagal nerve study, have uncovered an unexpected link between meditating or thinking ‘good thoughts’ and improvements in vagal tone. This sounds incredible, but the concept that physical health and psychological well-being are inextricably linked has also been noted in other related studies: "We all know these two are intricately connected, and in fact are integrated parts of one system," says Elissa Epel at the University of California, San Francisco.
Vagal tone is essentially measured by tracking your heart-rate alongside your breathing rate. "Your heart rate speeds up a bit when you inhale and slows down a bit when you exhale," says Fredrickson, "allowing freshly oxygenated blood to circulate more rapidly when you breath in and putting a brake on the heart’s tendency to race when you breathe out".

This simple action is controlled by the vagus nerve, but its effectiveness can vary significantly as each person has a different level of vagal tone. The variation is thought to be caused by genetic pre-disposition in approximately 65% of cases, but factors such as obesity and sedentary lifestyles people have been found to be associated with low vagal tone. An associate of Fredrickson, Bethany Kok, who is a social neuroscientist at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, commented that vagal tone was" about as variable as height".

Vagal tone peaks early in life, during childhood, possibly explaining why children are so much more emotionally connected, and why traumatic childhoods are thought to adversely affect its efficacy later in life. There is a steady decline in its performance through adolescence and then it stabilises in adulthood.

It is almost possible to pick out those individuals who are lucky enough to possess high vagal tone, as they are generally found to be happier, less stressed and less likely to suffer from depression than those with lower tone. They also have good memories, are better able to focus their attention, and have increased brain-power. They are usually healthier too, as the vagus nerve is involved in insulin production, cardiovascular health and immune responses.

Conversely, therefore, those with low vagal tone have been shown to suffer more from inflammatory conditions, strokes and cardiovascular problems, depression, diabetes, cognitive impairment and chronic fatigue syndrome. They may also be over-emotional and less sociable, confident and empathetic.

The results of the North Carolina study and other similar research programmes has led to different approaches in the treatment of depression, where vagal nerve stimulation has been used in cases where medication has failed.

During her research, Fredrickson attempted to improve vagal tone using loving kindness meditation, and she found that this increased feelings of social connectedness and emotional well-being in volunteers. This then began to create an ‘upward spiral’ as volunteers felt better, so their vagal tone improved, which in turn caused them to experience improved mental and physical health.

Though there is still more work to be done in the field, other scientists are intrigued by Fredrickson’s findings. Gary Berntson at Ohio State University in Columbus, who researches brain mechanisms underlying behaviour and emotions, would like to see more research on the causal pathways and mechanisms but commented: "It’s clearly speculative but she does have some neat data that support the speculations." Elissa Epel, a health psychologist focusing on stress pathways, was also impressed: "The vagus nerve is such an important connection between the brain and the heart, and also related to the immune system, and responsive to what we are doing and feeling."

So, what can you do to improve your vagal tone? Well, we have seen that thinking good thoughts has been shown to improve vagal efficiency, though the evidence suggests that, for those with low vagal tone, it can be tough to break the cycle initially. Regular meditation appears to be helpful and almost essential. Exercise has also been shown to be very beneficial and could be the easiest first step for those who are depressed and who find ‘positive thinking’ difficult. Due to the constant interplay between the brain and the gut, diet can also be a very important aid in vagal nerve activity; for example, omega-3 fatty acid intake can boost mood and vagal tone, and the presence of symbiotic gut bacteria can positively affect the action of the nerve, though the mechanism for this is not yet fully understood. Any dietary measures which improve overall health and well-being and lower weight, however, will have the potential to improve vagal tone, as will activities to reduce stress, which we have seen has negative effects on vagal performance and also adversely affects digestion.

In short, do what makes you feel good, think good thoughts about others, and also about yourself: Andy Martens at the University of Canterbury in Christchurch, New Zealand, found that hearing positive feedback about yourself can increase vagal tone, so this indicates that anything which enhances your self-esteem is also key.

Here at Unknown Country we try to make you feel better about yourself by understanding the truth about our bodies, our souls, the earth and the universe around us; we just need to open our hearts and minds.

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Anne Strieber has many diary entries on meditation. To see a list, click here.

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