Marked increase in high density lipoproteins in mountaineers.

Apoprotein-AI concentrations were measured in whole blood in 13 male mountaineers before, during and after a strenuous climb of 8 weeks' duration. The AI concentration almost doubled in 3 weeks and remained elevated at that level for the full period of the climb. This study demonstrates the rapid rate at which high density lipoproteins can rise and the very high levels (148 +/- 29 mg/dl in whole blood) that can be reached. The rise can be attributed at least in part to exercise though other factors such as exposure to cold, hypoxia and mental stress might also have contributed.