Why Deep Breathing May Keep Us Calm
By GRETCHEN REYNOLDS
For generations, mothers have encouraged children to take long, slow breaths to fight anxiety.
A long tradition of meditation likewise uses controlled breathing to induce tranquillity.
Now scientists at Stanford University may have uncovered for the first time why taking deep breaths can be so calming. The research, on a tiny group of neurons deep within the brains of mice, also underscores just how intricate and pervasive the links are within our body between breathing, thinking, behaving and feeling.
Breathing is one of the body’s most essential and elastic processes. Our breaths occur constantly and rhythmically, much like our hearts’ steady beating. But while we generally cannot change our hearts’ rhythm by choice, we can alter how we breathe, in some cases consciously, as in holding our breath, or with little volition, such as sighing, gasping or yawning.
But how the mind and body regulate breathing and vice versa at the cellular level has remained largely mysterious. More than 25 years ago, researchers at the University of California at Los Angeles first discovered a small bundle of about 3,000 interlinked neurons inside the brainstems of animals, including people, that seem to control most aspects of breathing. They dubbed these neurons the breathing pacemaker.
In the years since, though, little progress had been made in understanding precisely how those cells work.
But recently, a group of scientists at Stanford and other universities, including some of the U.C.L.A. researchers, began using sophisticated new genetics techniques to study individual neurons in the pacemaker. By microscopically tracking different proteins produced by the genes in each cell, the scientists could group the neurons into “types.”
They eventually identified about 65 different types of neurons in the pacemaker, each presumably with a unique responsibility for regulating some aspect of breathing.
The scientists confirmed that idea in a remarkable study published last year in Nature, in which they bred mice with a single type of pacemaker cell that could be disabled. When they injected the animals with a virus that killed only those cells, the mice stopped sighing, the researchers discovered. Mice, like people, normally sigh every few minutes, even if we and they are unaware of doing so. Without instructions from these cells, the sighing stopped.
So for the newest study, which was published recently in Science, the researchers carefully disabled yet another type of breathing-related neuron in mice. Afterward, the animals at first seemed unchanged. They sighed, yawned and otherwise breathed just as before.