What occurs during the Valsalva Effect?

The Valsalva Effect refers to a physiological response that occurs when an individual forcibly exhales against a closed airway, typically by holding the breath while bearing down. This maneuver has several distinct effects on the cardiovascular system, one of which is the temporary rise in blood pressure.

During the Valsalva maneuver, the increased intra-thoracic pressure from exhaling against a closed airway decreases venous return to the heart initially. This initial phase can lead to a drop in stroke volume and blood pressure. However, as the person continues to bear down, the body responds to maintain blood flow and compensate for the changes in pressure. The blood pressure temporarily rises due to reflexive adjustments in heart rate and systemic vascular resistance in response to the initial changes.

These compensatory mechanisms engage the autonomic nervous system, specifically through sympathetic stimulation, increasing vascular responsiveness. This is why the correct answer highlights the temporary rise in blood pressure during the Valsalva Effect.

Other options reflect different physiological changes that do not directly correlate with the primary outcomes of the Valsalva maneuver, such as respiratory and heart rate changes that can occur but are not the central feature of this specific response.