What makes Valsalva harmful according to the material?

• A. Bracing without breathing leads to increased internal pressure
• B. It increases metabolic rate drastically
• C. It improves circulation
• D. It reduces heart rate

Answer: (A)

The main idea here is that bracing and holding your breath during effort raises the pressure inside the chest. This increased intrathoracic pressure squeezes the veins, reduces venous return to the heart, and lowers the heart’s preload. The result can be a temporary drop in cardiac output and potentially dangerous blood pressure fluctuations, which is why this maneuver is considered harmful. So, the best answer identifies the harm as due to increased internal pressure from bracing without exhaling. The other statements don’t fit: metabolic rate isn’t drastically raised, circulation isn’t improved by this, and heart rate isn’t consistently reduced.