Effect of Altitude and Duration of Stay on Pulmonary Function in Healthy Indian Males

The study was carried out with the objective to investigate the effect of varying altitude and duration of exposure on blood pressure, heart rate and lung function parameters in healthy Indian soldiers after adopting proper acclimatization schedule. For this purpose 17 soldiers of Indian Army, weight and height matched, were studied after obtaining written consent. Recording of Blood pressure (systolic and diastolic), heart rate and lung function variables (FVC, FEV1, FEV1/FVC%, MVV, FEF25-75%, MEF 25%, MEF 50%, MEF 75%, PEF) were measured at basal (290m), 800m, 3200m (day 10 and day 20) and upon de-induction. Our results demonstrate that with increasing altitude FVC declined, FEV1 did not change and due to these changes FEV1/FVC% increased. Expiratory flow rates including MEF 25%, MEF50% MEF 75%, PEF and mean expiratory flow rate (FEF25-75%) increased upon induction to high altitude. This increase may be due to reduction in air density causing less air resistance which accelerates lung emptying. Though the increase upon induction in all the values was transient and returned to baseline values after de-induction. MVV reflecting respiratory muscle function increased significantly upon induction to altitude in our study and returned to basal values upon de-induction. Understanding respiratory system in mountainous regions and its further correlation with other systems pertaining to acclimatization could help in laying step in unveiling mechanism of human high altitude adaptation