Exercise Responses to Metabolic Function on High Altitude Pulmonary Edema Susceptible Individuals

Abstract

The study was aimed to evaluate and compare resting and exercise induced metabolic responses between acclimatized high altitude pulmonary edema (HAPE) susceptible (HAPE-s) and HAPE resistance (HAPE-r) volunteers at sea level. A group of 14 Indian soldiers volunteered for this study, divided into two groups, (i) HAPE-s, with past history of HAPE [n₁ = 7; age = 33.3 ± 4.5 (M ± SD)] and (ii) HAPE-r, with prior history of repeated exposure to high altitude and without suffering HAPE [n₂ = 7; age = 31.9 ± 4.2 (M ± SD)]. Respiratory frequency (f_R), tidal volume (_T), minute ventilation (_E), oxygen consumption (O₂), carbon dioxide output (CO₂), heart rate (HR) and respiratory quotient (RQ) were recorded on all the volunteers during resting and exercise conditions. Ventilatory equivalent for oxygen (EqO₂) and oxygen pulse (O₂P) were calculated. Significant differences were observed between HAPE-s and HAPE-r volunteers in f_Rrest (25.3% higher), O₂P_rest (23.7% lower), _Emax (50.9% lower) (all P<0.05), f_Rmax (55.7% lower), O_2max (55.5% lower), O₂P_max (34.2% lower) (all P<0.01) and CO_2max (42.1% lower, P<0.001). Rest of the parameters did not show any significant differences between the study groups. The study revealed that resting and exercise induced metabolic responses of HAPE-r volunteers was better as compared to acclimatized HAPE-s volunteers at sea level.