This is not to be confused with stage 4 of the Valsalva maneuver, in which the release of high intrathoracic pressure previously generated by forced expiration against a closed glottis, now restores venous return and cardiac output into a vasoconstricted circulation, stimulating the vagus nerve and leading to a slowing of the heart, or bradycardia.
This is not to be confused with stage 4 of the Valsalva maneuver. In this stage, high intrathoracic pressure from forced expiration against a closed glottis is released, which helps restore venous return and cardiac output in a vasoconstricted circulation, stimulating the vagus nerve and leading to a decrease in heart rate or bradycardia.