Relationship Between Changes In Cardio-pulmonary Function And The Peak Oxygen Uptake Decrease In Different Acute Hypoxia

Objective:To investigate the relationship between changes in cardio-pulmonary function and the peak oxygen uptake decrease in acute hypoxia. This study intends to observing in different acute hypoxic exposure, pulmonary ventilation function index (Ventilation(VE)), cardiac function index (cardiac output (CO) and stroke volume (SV), heart rate(HR)), blood oxygen ability evaluation index (oxyhemoglobin saturation(SpO2)) changes.Methods:12 healthy male college students performed maximal incremental test at sea level and simulated altitudes(2,500,4,500m). Each test two intervals for 14 days. Quiet when biochemical experiment, test index (E and NE); Test records quiet at the same time physiological indexes (VE, CO and SV, EF, HR, SpO2); Increasing load immediately after exercise, measured VE, CO, SV, EF, HR, SpO2, E, NE index.Results (1) In different acute hypoxia environment, VO2peak were 48.28 ±6.56 (ml/kg/min)、42.11 ±5.01 (ml/kg/min)、38.15±5.81 (ml/kg/min. The VO2peak significantly decreased at 4500m vs. sea level(P<0.01) and 2500m(P<0.05). The VO2peak significantly below sea level (P<0.05) at 2500m. As the altitude rises, the VO2peak at 2500m and 4500m compared with the sea level declines respectively (12.09±9.12)%、(20.18±12.20)%. 4500m from 2500m drop (9.04+12.25)%. (2) Under different altitude, the SpO2peak were (96.58±1.44)%、(88.08±2.75)%、(73±3.88)%, SpO2peak significantly decreased at 4500m vs. sea level (P<0.01) and 2500m(P<0.01). At 2500m, the SpO2peak significantly below sea level(P<0.01). The SpO2peak is significantly lower with the increase of altitude. (3) Under different altitude, the VEpeak were 105.69±13.04 (L/min)、110.48±14.41 (L/min)、117.2±15.65 (L/min), VEpeak significantly higher at 4500m than sea level(P<0.05) and 2500m(P<0.05). (4) There were no significantly change, the CO, SV, EF were respectively compared at maximal exercise, in sea level,2500m,4500m. HRpeak significantly decreased at 4500m vs. sea level (P<0.01) and 2500m(P<0.01). At 2500m, the HRpeaksignificantly below sea level(P<0.01). The HRpeak is significantly lower with the increase of altitude. (5) Under different altitude, E and NE significantly higher at 4500m than sea level (P<0.01) and 2500m(P<0.01). But there was no significantly change among 2500m and sea level.Conclusion (1) With the rise of altitude, VO2peak decreases. The higher the altitude, the deeper the degree of oxygen to the body, VO2peak dropped significantly. (2)In different acute hypoxia environment, Pulmonary ventilation function (VE)、The enthusiasm of the heart pump blood (HR)、 The ability to transfer oxygen(SpO2) were significantly changes at maximal exercise, with the rise of altitude. These three indicators may be the important factors that affect VO2peak decline. (3)In different acute hypoxia environment, The heart pumps blood ability(CO、SV、EF) remained unchanged, They may not be the main reason for decline in VO2peak.