Urinary catecholamine excretion on induction to high altitude (3,658 m) by air and road.

In a preliminary pilot study we had reported a significant difference in urinary catecholamine excretion between symptomatic and asymptomatic individuals inducted to high altitude by air. The present study covers slower induction by road; 25 lowlanders ascended from 1,800 to 3,658 m in 50 h and 33 similar subjects covered the journey in 6 h. They were studied according to the protocal used in the initial study. None of the 58 subjects inducted by road developed symptoms of high-altitude illness. Their urinary catecholamine excretion remained normal during the 10 days' stay at high altitude. These findings lend support to our earlier contention that there might be a relationship between increased sympathoadrenal activity and high-altitude illnesses.