As it turns out, deep breathing is not only relaxing, it's been scientifically proven to affect the heart, the brain, digestion, the immune system — and maybe even the expression of genes.
"The relaxation response is controlled by another set of nerves — the main nerve being the Vagus nerve. Think of a car throttling down the highway at 120 miles an hour. That's the stress response, and the Vagus nerve is the brake," says Sternberg. "When you are stressed, you have your foot on the gas, pedal to the floor. When you take slow, deep breaths, that is what is engaging the brake."