Haematological Studies in High Altitude Natives at Plains and on Return to High Altitude

Haematologic studies were carried out in 20 high altitude natives during two months stay at plains (200 m) and on their return to an altitude of 3,500 m. Haemoglobin, erythrocyte count, haematocrit and reticulocyte count decreased rapidly on arrival to plains and attained minimum level by the end of fourth week. All these parameters increased rapidly on return to high altitude and were found to attain maximum values by 23rd day on return to high altitude. Mean cell volume and mean cell haemoglobin showed significant increase at altitude. Blood volume and red cell mass increased significantly at altitude. It is concluded that the high altitude natives of Ladakh were well adapted to hypoxic environment due to normocythaemic hypervolemia.