https://www.google.com/search?q=valsalva+maneuver&client=ms-opera-mini-android&channel=new&tpsf=opminienpf
How to Perform the Maneuver:
Sit or lie down comfortably.
Take a deep breath.
Close your mouth and nose tightly.
Forcefully exhale as if you are blowing into a balloon.
Hold your breath for 10-15 seconds.
Release the breath slowly.
Physiological Effects:
Increased intrathoracic pressure, Decreased venous return to the heart, Increased heart rate, Decreased blood pressure, and Increased sympathetic nervous system activity.