Mechanisms of the Changes in Arterial Oxygen Saturation at Altitude,
Abstract
The reasons for the arterial oxygen saturation (SaO2) changes during altitude exposure at rest and during exercise are presented and discussed. SaO2 is prevented to show lower values than usually measured due to hyperventilation. Ventilation increases SaO2 through an elevation of P sub O2 and pH. No negative contribution is found with the rightward shift of the oxygen-hemoglobin (O2-Hb) dissociation curve reported in vitro. The explanation is found on similar P sub 50 in vivo values shown at sea level and at altitude. The SaO2 fall observed during exercise at altitude is fully explained by the metabolic acidosis (Bohr effect). However, if additional factors are taken into account, such as temperature increase and left shift of the O2-Hb dissociation curve, no changes are expected to occur in vivo. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 16, 1978
- Accession Number
- ADA052564
Entities
People
- James A. Vogel
- Julio C. Cruz
- L. Howard Hartley
Organizations
- United States Army Research Institute of Environmental Medicine