Which of the following best describes the effect of the Valsalva maneuver on blood pressure?

The Valsalva maneuver is a breathing technique that involves a forced expiration against a closed airway, typically by pinching the nose and keeping the mouth shut. This maneuver has a notable effect on cardiovascular dynamics, particularly blood pressure.

When a person performs the Valsalva maneuver, there is an initial increase in intrathoracic pressure, leading to a temporary increase in blood pressure. This is due to the acute compressive effects on the thoracic cavity, which affects venous return to the heart and increases stroke volume. The body initially responds to this increased pressure by increasing systemic vascular resistance, further contributing to the rise in blood pressure.

Furthermore, the subsequent phases of the Valsalva maneuver involve changes in blood pressure as the maneuver is sustained, and then there can be fluctuations post-maneuver; however, the immediate effect is a clear increase in blood pressure.

This understanding is crucial in exercise physiology, as the Valsalva maneuver is sometimes encountered during heavy lifts or other intense physical activities. It's important for fitness professionals to be aware of these physiological responses to guide clients safely during exercise.