The Influence Of Four-Week CO Breathing To Simulate High Altitude Training On Aerobic Capacity

Objective: After inhaling a bolus of carbon dioxide(CO),we detected the changes of carbonhemoglobin(HBCO)and erythropoietin(EPO)in blood.We also evaluated the long term effects of inhaling a bolus of CO before training in erythropoiesis,aerobic capacity,and the effectiveness of oxygen utilization in muscle.By evaluating the effects of hypoxia caused by CO,we investigated the effectiveness of CO as a new hypoxia training method.Methods: 12 male college students of Beijing Sports University volunteered to participate in this study.All subjects inhale a bolus of CO(1ml/kg BW)through a Spirometer,we then detected the changes of content of CO in exhale breath,the percent of HBCO in fingertip blood,and the EPO in venous blood.After an incremental exercise test,the subjects were ranked based on the maximal oxygen uptake.From the ranking,every two of the subjects were randomly assigned to the hypoxia group(HG)and control group(CG).Training speed was set at the speed of 90% ventilation threshold.All subjects trained 3 times a week for 4 weeks,each train section last for 40 min.Before training the subjects from hypoxia group inhale a bolus of mixed gas of CO and O2,and the subjects from control group inhale just a bolus of O2.Before and after 4 weeks’ training,the total hemoglobin mass(tHb),blood morphology,and maximal oxygen uptake(VO2max)were tested.Results:(1)After inhaling a bolus of CO,HBCO% significantly elevated from 0.7 to 5.81(p<0.05),then it gradually went down to 1.48 after 8 hours which is still significantly higher than 0.7;(2)After inhaling a bolus of CO,[EPO] significantly elevated after 2 hours(p<0.05),from 1.912 mIU/mL to 2.427 mIU/mL(26.9%),reached the peak 2.720mIU/mL(42.3%)after 4 hours then gradually went down;(3)tHb in HG significantly elevated from 918.5g to 972.5g(5.9%)after 4 weeks(p<0.05)while there was on such change in CG;(4)VO2max in HG significantly elevated from 4.78 l/min to 5.10 l/min(6.7%)after 4 weeks(p<0.05)while VO2 max in CG had no significant change;(5)the oxygen uptake at submaximal intensities significantly declined both in HG and CG(p<0.05),the change range of VO2 at speeds of 8km/h,10 km/h,12 km/h are,HG 25.7%,23.9%,16.8%,CG 17.6%,16.2%,16.2% separately.Conclusions: Inhaling a bolus of CO(1ml/kg BW)can elevate the [EPO] in blood which reaches peak after about 4 hours;the hypoxia training caused by CO can elevate the tHb and VO2 max and reduce the energy costed during lower speeds.