Question

People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 meters have around 8 million. This is because at high altitude

• A. People eat more nutritious food and therefore more RBCs are formed.
• B. People get pollution-free air to breathe and more oxygen is available.
• C. Atmospheric $O_2$ level is less and hence ,more RBCs are needed to absorb the required amount of $O_2$ to survive.
• D. There is more UV radiation which enhances RBC-production.

Answer 1

The correct option is C Atmospheric $O_2$ level is less and hence ,more RBCs are needed to absorb the required amount of $O_2$ to survive.

The amount of haemoglobin in the blood increases with altitude. A person has more haemoglobin than the normal at high altitude. This is one of the best-known features of acclimatisation (acclimation) to high altitude. Increasing the amount of haemoglobin in the blood increases the amount of oxygen that can be carried. However, there is a downside: when there is too much haemoglobin, blood becomes sticky and viscous and it is harder for the heart to pump the blood around the body. This happens in chronic mountain sickness.