Effects of a cable car trip on blood pressure and cardiovascular hormones in lowlander and highlander normotensives.

The effects of a cable car trip from 1370 m (4500 ft) to 3460 m (11350 ft) were studied in 6 lowlanders (3 men and 3 women, mean age 31 +/- 4 years, living at an altitude of less than 500 m) and in 10 highlanders (all males, mean age 37 +/- 12 years, ski teachers and cable car workers working for greater than or equal to 6 months/year at a greater than 3000 m). Cuff blood pressure (BP), heart rate, plasma catecholamines, serum renin, aldosterone, ACTH and cortisol were measured immediately before and 20 min after the trip, at rest and at the same air temperature. A handgrip test was also performed under the same conditions. At baseline, lowlanders and highlanders showed significant differences in diastolic BP (86 +/- 5 mmHg in lowlanders and 91 +/- 4 mmHg in highlanders, p = 0.05), plasma noradrenaline (323 +/- 114 pg/ml in lowlanders and 585 +/- 255 in highlanders, p less than 0.05), serum renin (10 +/- 6 pg/ml in lowlanders and 17 +/- 8 in highlanders, p less than 0.05), and serum cortisol (163 +/- 54 ng/ml in lowlanders and 120 +/- 25 in highlanders, p less than 0.01). The acute exposure to high altitude did not modify BP, heart rate or any of the measured cardiovascular hormones in either group. The handgrip test provoked a significant increase in systolic and diastolic BP in both lowlanders and highlanders (p less than 0.01), and this response was not modified by the change in altitude; however, highlanders showed significantly smaller increases in systolic BP than lowlanders at both altitudes (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)