After-Effects of a High Altitude Expedition on Blood

The aim of the study was to investigate blood alterations caused by altitude acclimatization which last more than lew days after return and might play a role for exercise performance at sea level. Measurements were performed in 12 moumtaineers before, during and either 7/8 or 11/12 days after a Himalaya expedition (26 - 29 days at 4900 to 7600 m altitude). [Erythropoietin] rose only temporarily at altitude (max. +11 ± 1 [SE] mu/ml serum). After return hemoglobin mass (initially 881 ± 44 g, CO-Hb method) was increased by 14 % (p < 0.01); aspartate aminotransferase activity in erythrocytes (initially 682 ± 25 U/I) was augmented (day 7: + 964 ± 152 U/I, day 11: + 533 ± 107 U/I) indicating reduced mean cell age. Calculated blood volume (+ 14 %) was influenced by red cell formation at altitude but also by plasma expansion at sea level. The haIf saturation pressure for Hb-O₂ (pH 7.4, 37 °C) as well as the 2,3-diphosphoglyceirate concentration were already initially high (32.1 ± 0.5 mmHg, 20.5 ± 0.7 μmol/g Hb) and showed only a nonsignificant tendency to increase after return. Also Hill's n was consistently high in the mountaineers, whereas the Bohr coefficients were slightly increased only after descent. Probably the preparatory physical training, partly in the Alps, and the stay in the Himalaya influenced O₂-affinity for a prolonged time. The adaptations might reduce the loss of physical performance capacity at altitude and be part of altitude training effects.

Key words

Acid-base-status - altitude training - blood volume - oxygen affinity