The Valsalva maneuver is performed by exhaling with force against a closed airway. This is done by exhaling while closing the mouth and pinching the nose shut, as if one were trying to block a sneeze. It is sometimes performed to clear built-up pressure in the ears, as can happen when flying, or by medical professionals as a cardiac test.
Although one rarely hears the term, the Valsalva maneuver is very much a routine part of life. Individuals who are sick with the common cold may use it to clear their nasal cavities. Scuba divers, airline passengers and mountaineers often use it to equalize pressure in the head built up from changes in elevation. The maneuver is also sometimes used to help pass objects through the body, such as during a bowel movement or by a pregnant mother bearing down while pushing during labor.
The maneuver can also be used in medical exams by healthcare professionals who are running tests to assess cardiac function and the autonomic nervous control of a person's heart rate. When the action is performed, the flow of blood through the veins and the heart is altered. Medical professionals can monitor these changes to potentially detect abnormalities in blood pressure and heart function. While it's medically encouraged in some cases, the maneuver is often discouraged among people who do not have healthy hearts. The sudden shift in blood pressure and flow caused by it can cause cardiac arrest and strokes in some individuals.
People exerting great physical force must also be aware of the adverse effects of the Valsalva maneuver, which the body performs involuntarily while lifting heavy objects. Due to the pressure it creates, it can help individuals lift heavy objects, but this is dangerous because of the effect it has on blood flow. When lifting weights and holding one’s breath, the pressure can cause dizziness and disorientation, which at the worst can cause individuals to pass out while holding a heavy object. The proper and safest breathing technique for lifting objects is to exhale as pressure is being exerted, so as to alleviate the pressure build-up and maintain a normal blood flow.
As effective as the maneuver is in alleviating pressure build-up in the ears, it can also cause damage if done incorrectly. This is particularly true when diving under water, as pressure rapidly builds up the more one descends. If the act is employed too forcefully, it can cause ear barotrauma, or injury to the inner ear caused by intense changes in barometric pressure.