A person remaining at high altitudes for years becomes more and more acclimatised to the low pO₂ by all the following adaptations except 

A person remaining at high altitudes for years becomes more and more acclimatised to the low pO₂ by:

• Increasing pulmonary ventilation
• Increasing production of RBCs and Hb content
• Polycythemia

Decreased cardiac output permanently is not an adaptation of people at high altitudes.