For most people, breathing is an automatic unconscious and subconscious function. Yet there are people who master this autonomic function with conscious breathing, thus producing the ability to relax, to withstand extreme conditions, and to be mentally, emotionally, and physically healthy.
Wim Hof, Leonard Orr, and other breath practitioners have shown that certain breathing techniques can dramatically increase longevity. Scientists studied Wim Hof and a group of volunteers he taught. Remarkably, the breathing techniques strengthened their immune systems enough so that they could be injected with e-Coli bacteria and not get sick.
Wim Hof teaches a 3-part method of breath control, concentration, and exposure to the cold. This reduces inflammation and produces a state of alertness.
The ability to influence the autonomic nervous system means that people do not have to be victims of the environment. They can develop the capacity to respond to conditions of stress and remain calm, healthy, and invigorated.
You can learn more about Wim Hof and using breath and cold showers to produce these benefits. Various youtube videos, e-books, and articles detail his methods and show the extensive research conducted by scientists on the efficacy of these practices.