Each system has its purpose, but when the sympathetic system has been at the wheel for too long, you start to feel stressed.
Wim Hof Method breathing stimulates the parasympathetic system, thus counteracting the sympathetic system and bringing stress levels down.
“The parasympathetic system is directly connected to the heart via the sinus node, a conjunction of nerves”, explains Cristopher Kopplin of the University of Bayreuth. "There is a phenomenon called sinus node arrhythmia, where exhalation increases parasympathetic activity, and consequently, lowers heart rate and makes us calm down. Deep, slow, and rhythmic breaths maximize this effect.”
A 2022 study put this to the test: subjects who did Wim Hof Method breathing reported markedly lower stress levels than people who breathed the old fashioned way.