When you're a hundred meters underwater and don't have any air, the fine line dividing calmness and anxiety also separates life from death. Jacques Mayol, the subject of Luc Besson's film The Big Blue, was the first person to achieve this, in 1976. He famously used yogic breathing techniques to stay calm under the ocean. Record-breaking "Iceman" Wim Hof is also known for using yogic breathing to achieve extraordinary self-control.

Far beyond the realms of frozen water, we're often told that controlling how we breathe can make us calmer. We know it works, but we don't know why. A new Stanford study has just shed some light on the answer.

What we already knew

The medulla in the brain contains a network of nerves called the "pre-Bötzinger complex" which generates the rhythm of breathing. The "locus coeruleus" is a region in the brain that is tightly linked with the brain's emotion and fear centres and plays a powerful role in generating the stress response. We know that the rhythm of the locus coeruleus is coupled with the rhythm of breathing but we don't know why.

What the study found

Some nerves in the pre-Bötzinger complex directly project to the locus coeruleus, which explains why breathing and arousal are so tightly coupled.

Normally, if you put mice in a new cage, they breathe faster. In response, the locus coeruleus makes the mouse aroused. When the Stanford researchers blocked the nerves from carrying messages to the locus coeruleus, the mice were no longer aroused through rapid breathing. They were mellow and relaxed when they were placed in the new cage.In homage to the yoga technique of Pranayama breathing, the researchers have labelled the nerves "Pranayama neurons".

The study's findings imply that if we regulate how we breathe, we may be able to control the activity of the locus coeruleus and mute the stress response it propagates.

Studies on humans

The Stanford study was done on mice and it's possible that the pathway may be different in humans. There are, however, several studies on humans that have shown how breathing slower and deeper can reduce sympathetic activity and help to calm a stress response:

  • In one study on patients with heart failure, slowing breathing to an average of seven breaths per minute and increasing the depth of each breath, reduced sympathetic activity by almost one third.
  • In another study, healthy volunteers breathing at six breaths per minute lowered their heart rate and blood pressure after just five minutes.

Taking action

A stress response is like a snowball turning into an avalanche. If you control your stress response when it is still a snowball, you might be able to stem its tide.The locus coeruleus sits at the level of the snowball. Assuming what happens in mice also happens in humans, controlling the locus coeruleus with your breathing at the earliest stages of a stress response will prevent that snowball from turning into a full-blown avalanche.