“…Another way to stimulate the VN is through deep breathing (DB) exercises [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The mechanisms through which DB stimulates the VN are not well established, but are believed to include peripheral factors, such as the baroreflex, the peripheral chemoreflex, the Bainbridge reflex, and the Heuring–Breuer reflex, as well as such central elements as the respiratory and cardiovascular centers in the brainstem [ 38 ].…”