What is the normal systemic vascular resistance (SVR) range?

• A. 600-1000
• B. 800-1200
• C. 1200-1600
• D. 400-800

Answer: (B)

Systemic vascular resistance is the pressure the heart has to overcome to push blood through the entire systemic circulation, mainly determined by arteriolar tone. In a healthy adult at rest, SVR typically falls within about 800 to 1200 dynes·sec·cm⁻⁵ (roughly 9–12 Wood units). This range comes from the relation SVR = (MAP − right atrial pressure) / cardiac output × 80, and it represents the balance of vascular tone and cardiac output under normal conditions. Values lower than this usually indicate vasodilation, while higher values point to vasoconstriction or other states increasing afterload. So, the normal SVR range is the 800–1200 dynes·sec·cm⁻⁵ region.