Question

What are the main mechanisms that explain why VO2 max is decreased at high altitude (e.g., 5000m)? (200 words)

Answer 1

VO2 max is defined as the maximum amount of oxygen consumed by the body during exercise or other strenous activities.
VO2 max can be ised as an indicator for aerobic capacity of an individual.
As the altitude rises the amount of oxygen in the air reduces. This causes reduced amount of oxygen available to the lungs. When the blood has low levels of oxygen it causes less amount of oxygen delivered to muscles. This decreases VO2 max.
The stroke volume is the amount of blood ejected by heart during each contraction. The stroke volume decreases at high altitudes resulting in low cardiac output. This reduces the blood plasma volume.
This in turn decreases the VO2 max.
People living at high altitudes adapt to low levels of oxygen available in atmosphere by increasing the RBC production.
The hematocrit levels of people living at high altitudes is higher than people living at sea level.