HMS, BM EQ-Bank 64 MC

During exercise at high altitude (3000 metres above sea level), which of the following adaptations occurs first in the body?

Increased production of red blood cells
Increased breathing rate and depth
Increased cardiac output
Increased capillarisation

Show Answers Only

\(B\)

Show Worked Solution

B is correct: The immediate response to high altitude is hyperventilation to compensate for lower oxygen partial pressure

Other Options:

A is incorrect: RBC production (erythropoiesis) takes several days to weeks
C is incorrect: While cardiac output increases, it’s secondary to respiratory changes
D is incorrect: Capillarisation is a long-term adaptation