THE AFFINITY OF HEMOGLOBIN FOR OXYGEN AT SEA LEVEL AND AT HIGH ALTITUDES

Abstract

The position of the O2 dissociation curve has been detd. in arterial blood obtained from a) 17 healthy adult c?? living at sea level; b) 12 Indian native residents of Morococha (Peru), at an altitude of 4,540 meters (14,890 ft.). The same detn. was repeated in 12 subjects of the 1st group within the 1st 2 hrs. after arrival at the high altitude, and in 8 men of the 2d group also within the 1st 2 hrs. after arrival to sea level. The results were compared with those obtained in previous investigations. There seems to be enough evidence to conclude that in humans, newcomers or residents, at altitudes of about 4,000 meters, or higher, there is no increased affinity of the blood Hb for O2. On the contrary, the findings indicate a slight tendency toward a lower affinity, both at arterial pH and a standard pH of 7.4, especially in the native residents. This right shift in the O2 dissociation curve at high altitude may be interpreted as a favorable compensatory adjustment to the low pressure environment.