PERCEIVED EXERTION DURING HYPOBARIC HYPOXIA IN LOW-ALTITUDE AND MODERATE-ALTITUDE NATIVES

Ratings of perceived exertion (RPE) were examined in six low- (LAN) an d eight moderate- (MAN) altitude natives during exercise at their resi dence (home) altitude (366 m and 2,200 m, respectively) and 1-4 wk lat er following 2-d decompression to 4,270 m (447 mm Hg). Cardiorespirato ry, plasma lactate, and differentiated RPE measures were obtained at e xercise intensities representing 35, 55, 75, 85, and 100% VO2peak. In general, cardiorespiratory and plasma lactate values were similar in L AN and MAN at their residence altitudes and during hypobaric hypoxia. However, the decrease in VCO2 was greater (P < 0.05) in LAN than MAN. At their residence altitudes, both LAN and MAN reported local RPE valu es that were greater (P < 0.05) than central ratings at the moderate t o high exercise intensities. At 447 mm Hg, central and local RPE were similar in LAN. However, there was a significant correlation between a cute mountain sickness (AMS) symptoms and central RPE (r = 0.875) acro ss the five exercise intensities in LAN. The differences between the c entral and local RPE noted in MAN during their residence testing also persisted at 447 mm Hg. Thus, differentiated ratings of perceived exer tion were similar in MAN at their residence altitude and at 4,270 m, b ut not in LAN subjects. Several factors, including AMS, may have contr ibuted to this group difference in the RPE response.