At what percentage of water loss in the body does death occur?

At what percentage of water loss in the body does death occur?

• A. 5% (roughly 2.5 litres)
• B. 15% (roughly 7.5 litres)
• C. 25% (roughly 12.5 litres)
• D. 40% (roughly 20 litres)

Answer: (C)

Losing a lot of body water directly reduces blood volume, which lowers how much blood returns to the heart and how much the heart can pump. The body can compensate at smaller losses through thirst and hormones that conserve water, helping maintain blood pressure. But once about a quarter of the body's water is gone, plasma volume falls enough that blood pressure can no longer be maintained and organs stop getting enough blood and oxygen. This sets the stage for hypovolemic shock and potential multi‑organ failure, making death likely if fluids and electrolytes aren’t restored quickly. For many adults, roughly 12–13 litres of water loss corresponds to 25% of total body water, which is why that level is used as a rough threshold. Smaller losses are usually manageable, while very large losses (around 40%) are catastrophic without rapid intervention.

Losing a lot of body water directly reduces blood volume, which lowers how much blood returns to the heart and how much the heart can pump. The body can compensate at smaller losses through thirst and hormones that conserve water, helping maintain blood pressure. But once about a quarter of the body's water is gone, plasma volume falls enough that blood pressure can no longer be maintained and organs stop getting enough blood and oxygen. This sets the stage for hypovolemic shock and potential multi‑organ failure, making death likely if fluids and electrolytes aren’t restored quickly. For many adults, roughly 12–13 litres of water loss corresponds to 25% of total body water, which is why that level is used as a rough threshold. Smaller losses are usually manageable, while very large losses (around 40%) are catastrophic without rapid intervention.