Altitude training adaptations often include which physiological change?

Altitude training adaptations often include which physiological change?

• A. Increased capillarisation
• B. Increased lactate tolerance
• C. Increased number of red blood cells
• D. Increased blood viscosity

Answer: (C)

Exposure to high altitude creates a hypoxic environment, so the body adapts mainly by boosting its ability to transport oxygen. The key response is increased production of red blood cells, driven by more erythropoietin released in the kidneys. With more red blood cells, there is more hemoglobin available to carry oxygen from the lungs to the muscles, improving the oxygen-carrying capacity and helping performance after acclimatization. Other potential changes can occur with endurance or altitude training, such as some improvement in capillary density or metabolic adjustments, but the standout and most direct adaptation at altitude is the rise in red blood cell numbers. A higher hematocrit can raise oxygen transport, while an increase in blood viscosity is a possible side effect of more cells, which can slightly hinder flow if excessive.

Exposure to high altitude creates a hypoxic environment, so the body adapts mainly by boosting its ability to transport oxygen. The key response is increased production of red blood cells, driven by more erythropoietin released in the kidneys. With more red blood cells, there is more hemoglobin available to carry oxygen from the lungs to the muscles, improving the oxygen-carrying capacity and helping performance after acclimatization.

Other potential changes can occur with endurance or altitude training, such as some improvement in capillary density or metabolic adjustments, but the standout and most direct adaptation at altitude is the rise in red blood cell numbers. A higher hematocrit can raise oxygen transport, while an increase in blood viscosity is a possible side effect of more cells, which can slightly hinder flow if excessive.