Breath
slowing their breathing to increase their carbon dioxide. This technique worked for panic attacks, too.
James Nestor • Breath: The New Science of a Lost Art
scientific methods have confirmed that changing the way one breathes can improve problems with anger, depression, and anxiety5 and that yoga can positively affect such wide-ranging medical problems as high blood pressure, elevated stress hormone secretion,6 asthma, and low-back pain.
Bessel van der Kolk • The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma
Kelder described these techniques in a slim booklet titled The Eye of Revelation, published in 1939.