AFTER-EFFECTS OF A HIGH-ALTITUDE EXPEDITION ON BLOOD

The aim of the study was to investigate blood alterations caused by al titude acclimatization which last more than few days after return and might play a role for exercise performance at sea level. Measurements were performed in 12 mountaineers before, during and either 7/8 or 11/ 12 days after a Himalaya expedition (26-29 days at 4900 to 7600 m alti tude). [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 amino transferase activity in erythrocytes (initially 682 +/- 25 U/l) was au gmented (day 7: + 964 +/- 152 U/l, day 11: + 533 +/- 107 U/l) indicati ng reduced mean cell age. Calculated blood volume (+ 14%) was influenc ed by red cell formation at altitude but also by plasma expansion at s ea level. The half saturation pressure for Hb-O-2 (pH 7.4, 37 degrees C) as well as the 2,3-diphosphoglycerate concentration were already in itially high (32.1 +/- 0.5 mmHg, 20.5 +/- 0.7 mu mol/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 coefficie nts were slightly increased only after descent. Probably the preparato ry physical training, partly in the Alps, and the stay in the Himalaya influenced O-2-affinity for a prolonged time. The adaptations might r educe the toss of physical performance capacity at altitude and be par t of altitude training effects.