by Juliette Siegfried
One of the most fascinating areas of modern medical research has to do with the relationship between the brain and the body, and the often surprising ability of the former to keep the latter healthy or actually cure diseases. One of the most well-known aspects of this research involves the placebo effect. In clinical drug trials, subjects given an inert sugar pill (the placebo) often show as much relief from their symptoms as those given the actual drug being tested.
While this is problematic in the extreme for the manufacturers of the drugs, who are increasingly being unable to prove them more effective than placebos, it opens new opportunities to other researchers, who are less interested in the drugs (not making any money from them, after all), and more interested in the curious fact that the mind seems to have the ability to heal the body. That, after all, is exactly what is happening when a person "responds" favorably to an inert pill that does absolutely nothing, and gets better anyway.
We know that the mind can heal the body, but how?
That was the basic question driving the research performed recently by Barbara Fredrickson and Bethany Kok at the University of North Carolina at Chapel Hill, and published in the journal Psychological Health. Following up on previous research that indicated that emotions do have a strong effect on an individual's health, they focused their efforts on what they suspected was the cause of this effect – the vagus nerve. This nerve has its origin point in the brain, but then runs in numerous branches to the heart and other abdominal organs. Its job is to transmit messages to these organs that it is OK to slow down and relax – "chill out" – during moments of relative calm and safety.
The relative health and functioning of the vagus nerve can be fairly easily determined by monitoring a person's heart rate as they breathe in and breathe out. If the vagus nerve is healthy, what is seen is a slight increase in heart rate while breathing in, and a slight decrease in heart rate when breathing out. The difference between these two readings results in a measurement called the vagal-tone index. Higher values indicate a healthy vagus nerve and have been associated with good health and are indicative of high vagal tone; lower values have been associated with inflammation and heart attacks, and are indicative of low or poor vagal tone.
Recent research has shown that people with high vagal tone are better than others at preventing negative emotions and bad feelings from becoming overblown, and that they experience more positive emotions than people with low vagal tone. To test this, and to see whether vagal tone could be improved – and with it, health – they recruited 65 subjects from the university's staff and measured their vagal-tone index at the start of the research. They also documented the subjects' daily reactions to a website designed to produce nine positive emotions (such as love, hope, and joy) and eleven negative emotions (such as anger, disgust, and boredom), asking them to rate how strongly on a scale of 1 to 5 they had felt each emotion.
Then half of the subjects were invited to participate in workshops in which a licensed therapist taught them a meditation technique designed to promote good feelings, both towards others and towards oneself (positive self-esteem). This group meditated daily using the technique, while the other group made no changes in their lifestyles or activities. Then both groups' vagal-tone index was measured again and the emotion-rating experiences were repeated.
Positive feelings increased the health of the vagus nerve
What they found was that in the meditating group, the subjects' vagal-tone index increased, while it remained the same in the non-meditating group. Also, among the meditating group, subjects who began the study with higher vagal tone values saw the most significant increases in positive emotions. What this indicated to the researchers was a positive feedback loop – those who started the study more emotionally positive benefitted more from the meditation technique designed to make them even more positive. Those who started the study more emotionally negative didn't benefit as much.
While this sounds like a "catch-22," and as if you can only get a psychosomatic health boost if you're already an emotionally positive person and meditate every day, follow-up experiments by the same researchers showed that a simpler, less time-intensive technique than meditation also improved vagal tone, and enabled those with a more negative emotional outlook to become more positive, thus improving their vagal-tone index as well.
While more conclusive links between positive emotions and high self-esteem and an improved state of health need to be established in follow-up studies, this preliminary research is still valuable in that it establishes that the vagus nerve may be one of the mechanisms that enables the placebo effect to work. It also establishes that the health of the vagus nerve can be improved, by simple means. So these scientists may have made some significant inroads into discovering how having more positive emotions may help to keep us healthy physically.
Juliette Siegfried, MPH, has been involved in health communications since 1991. Shortly after obtaining her Master of Public Health degree, she began her career at the National Institutes of Health in Bethesda, Maryland. Juliette now lives in Europe, where she launched ServingMed(.)com, a small medical writing and editing business for health professionals all over the world. Circle Juliette on Google+!