Blood pressure responses in young adults first exposed to high altitude for 12 months at 3550 m

Siqués, Patricia, Julio Brito, Jose R. Banegas, Fabiola Léon-Velarde, Juan J. de la Cruz-Troca, Vashti Lopéz, Nelson Naveas, and Rafael Herruzo. Blood pressure responses in young adults first exposed to high altitude for 12 months at 3550 m. High Alt. Med. Biol. 10:329-335, 2009.-To determine the changes in blood pressure (BP) and related variables in sea-level young adults with chronic exposure to high altitude, a longitudinal study was performed in male army recruits (n Combining double low line 346; age 17.9 ± 0.1 yr; BMI, 22.5 ± 0.3 kg/m2) first exposed to 3550-m altitude for 12 months. Fifty male recruits (age 17.8 ± 0.6 and BMI 22.6 ± 0.3 kg/m2) never exposed to altitude were used as controls. A sustained higher mean diastolic BP (DBP) (82.1 ± 1.0 mmHg at month 3; 81.3 ± 0.9 mmHg at month 12) was observed, compared to first exposure and the control group (p < 0.001). The BP values were always higher than those of the sea-level control group (systolic blood pressure (SBP) 109 ± 2.3 and DBP 67.4 ± 0.8; p < 0.001), and a large proportion of subjects steadily presented overoptimal values for either systolic BP (SBP) (64%) or DBP (77%) and hypertensive DBP values (40%). The higher DBP was associated with lower Sao2 (OR Combining double low line 0.919; p < 0.05). In addition, the acute mountain sickness (AMS) score showed a slight decrease during re-exposure (3.9 ± 0.3 vs.3.4 ± 0.3; p < 0.001) and an inverse association to the before-descending Sao2 at month 3 (OR Combining double low line 0.906, p < 0.01). These data suggest that BP stabilization can take longer than currently thought and that each parameter has a different profile of change. Further, a sustained high DBP should be a matter of epidemiological concern and emphasizes the need for BP monitoring among young lowlanders exposed to high altitude.