title: Chronic intermittent hypoxia at high altitude exposure for over 12 years: assessment of hematological, cardiovascular, and renal effects.
abstract: The aim of this cross-sectional study was to assess the health status of subjects weekly commuting between sea level and 3550-m altitude for at least 12 yr (average 22.1 +/- 5.8). We studied 50 healthy army men (aged 48.7 +/- 2.0) working 4 days in Putre at 3550-m altitude, with 3 days rest at sea level (SL) at Arica, Chile. Blood pressure, heart rate, Sa(O(2) ), and altitude symptoms (AMS score and sleep status) were measured at altitude (days 1, 2, and 4) and at SL (days 1, 2, and 3). Hematological parameters, lipid profile, renal function, and echocardiography were performed at SL on day 1. The results showed signs of acute exposure to hypoxia (tachycardia, high blood pressure, low Sa(O(2) )), AMS symptoms, and sleep disturbances on day 1, which rapidly decreased on day 2. In addition, echocardiographic findings showed pulmonary hypertension (PAPm > 25 mmHg, RV and RA enlargement) in 2 subjects (4%), a PAPm > 20 mmHg in 14%, and a right ventricle thickness >40 mm in 12%. Hematocrit (45 +/- 2.7) and hemoglobin (15 +/- 1.0) were elevated, but lower than in permanent residents. There was a remarkably high triglyceride level (238 +/- 162) and a mild decrease of glomerular filtration rate (34% under 90 mL/min and 8% under 80 mL/min of creatinine clearance). In conclusion, in these preliminary results, in chronic intermittent hypoxia exposure even over longer periods, most subjects still show symptoms of acute altitude illnesses, but a faster recovery. Findings in triglycerides, in the pulmonary circulation and in renal function, are also a matter of concern.
authors.affiliation: Instituto de Estudios de Salud, Universidad Arturo Prat, Iquique, Chile. jbritor@tie.cl
authors.forename: Julio
authors.initials: J
authors.lastname: Brito
authors.forename: Patricia
authors.initials: P
authors.lastname: Siqués
authors.forename: Fabiola
authors.initials: F
authors.lastname: León-Velarde
authors.forename: Juan José
authors.initials: JJ
authors.lastname: De La Cruz
authors.forename: Vasthi
authors.initials: V
authors.lastname: López
authors.forename: Rafael
authors.initials: R
authors.lastname: Herruzo
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D001794:Blood Pressure; D002677:Chile / Q000453:epidemiology; D002784:Cholesterol / Q000097:blood; D002908:Chronic Disease; D003401:Creatine / Q000097:blood; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D004781:Environmental Exposure; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D006339:Heart Rate; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000706:statistics & numerical data*; D012307:Risk Factors