What does the Valsalva maneuver primarily do?

The Valsalva maneuver involves a person attempting to exhale forcefully while keeping the airway closed, typically by closing their mouth and pinching their nose. This action creates significant pressure in the thoracic cavity, which can have physiological effects on the body. One of the primary outcomes of this maneuver is the alteration of blood pressure and heart rate, as the increased intrathoracic pressure temporarily decreases venous return to the heart, which can affect circulation and may lead to headaches or other discomforts for some individuals.

The relationship between the Valsalva maneuver and headaches is particularly noteworthy. When the maneuver is performed, changes in intracranial pressure can occur, and this may trigger headache in susceptible individuals, especially if it is done improperly or excessively. Additionally, the technique is sometimes used in clinical settings to identify certain medical conditions, such as autonomic dysregulation or to clear ear pressure.

In contrast to the other options, which do not align with the primary physiological effects of the Valsalva maneuver, it is specifically the action of forcing air against a closed airway that leads to various cardiovascular responses and can indeed trigger headaches in some people. This makes choice B the most accurate description of what the Valsalva maneuver primarily does