Velocity Of CBF Of Common Athletes With Moderate Constant Exercise During Acute And Chronic Intermittent Hypoxic Exposure

PURPOSE:The purpose of this study was to investigate the effects of intermittent hypoxic exposure using normobaric hypoxic house on velocity of cerebral blood flow with moderate constant exercise so as to provide some theory for living high-training low .METHODOLOGY: Eight sea-level native males exposed to normobaric hypoxic house 10 hours every day for 4 weeks. The cerebral blood flow(CBF) velocity with moderate constant ergometer cycling exercise was measured by transcranial Doppler at rest ,exercise 5 min ,exercise 10 min ,exercise 15 min and after exercise instantly during normoxia, acute hypoxia and the 4-week chronic intermittent hypoxic exposure. Arterial saturation oxygen, the percent content of O₂ and CO₂ of the expired gas, hemoglobin (Hb), Hct were also measured.CONCLUSION:1. The mean velocity of CBF increased continually during acute exposure, indicating the response time of cerebral circulation to acute hypoxia exceeded 20 min;2. The increase of CBF is caused by Vd mainly duting acute hypoxia.3. The body cannot develop effective ventilatory response to depend the double hypoxic stimulus of environmental hypoxia and kinetic hypoxia during acutehypoxic exercise.4. The velocity of CBF with exercise during Iwk intermittent hypoxia is mostprofoundly affected.5. The percent of velocity of CBF with moderate constant exercise compared with the rest value during 4-week intermittent hypoxic exposure fluctuated with the extension of exposure week. The percent values of Exposure 1 wk and exposure 3 wk were low, and the percent values of Exposure 2 wk and exposure 4 wk were high.