Chapter-1 / Physiological Foundations - WHNLive Public Library

~IUI1!J ~atpWorMs---~~·tIIlDkeJ \IUI1!J:1iojItff htarl8c~ ptJrlil/lptPJSlUD/orItrits~7trJPItv;sv,~3.sIttItIiI~ 3/i$sueIhtorllininIh"!'~·rtIitJa)renae ctmltanir9rt htorfI'" Vo 20 40 60 80 KJO 120POI •.. 1\.Fig. 9 02 partial pressures (A) and C02 partialpressures (B) of the blood in the variou~ sectionsof the circulatory system under restingconditionson chemical [16] or other ways to overcomethe membrane barrier, without losing the IHPeffect [45]. Because of its complicated natureand the fact that it is effective for only 60 days,this method has not as yet been of practicalsignificance. It should be pointed out in thissection that, according to [46], the DPG concentrationin erythrocytes is increased byroughly 20 % by intensive physical training.Next to the slight shifting of the O 2 equilibriumcurve to the right, caused by this, a flatteningof the curve and an increased venousresting P02 can be observed in competitivesportsmen.1.1.5 The determination of the resting O 2 status and further characteristic values1.1.5.1 Definition of the resting O 2 statusThe absolute characteristic value for the restingO 2 status be defined as the spirometricallydetermined O 2 absorption of the organism viathe lung under conditions of physical rest.Strictly speaking, the O 2 absorption is given asthe sum of the two contributions Q02 andQ'02, with Q02 representing the O2 transportto the organs and tissues by means of O 2 loadingand O 2 discharging of the hemoglobin inthe blood circulation, and Q'02 representingthe O 2transport by direct O 2 diffusion fromthe lumen of the arterial vessels to special tissues(e.g. arterial walls, vitreous body, cartilage,etc.). As Q'02 < Q02' it is generally sufficientfor consideration of the balance, to use Q02alone as an (absolute) characteristic value forthe resting O 2 status.he numerical value of Q0 2 is, according toble 2 a product of three factors. Fast andgr at f1~ctuations are only observed in the firstfactor, the O 2 saturation difference 1'1 of theblood. The momentary resting level of 1'1 istherefore a relative characteristic value for themomentary O 2 status, with information contentofhigh diagnostic significance.The second factor, the resting Cflrdiac outputnormally changes only slowly with training conditionand age.The third factor, the hemoglobin content Hbof the blood usually remains roughly constantin the individual case, also over longer timespans.11 The hemoglobin content is known to be temporarilyreduced to roughly 66 % of its starting level,with the hemodilution method [47). Nevertheless, asignificant increase in the 02 transport to the bodytissue results, particularly because the venous P01drops, and the great increase in T} and in cardiac outputwhich then occur, greatly overcompensate for theinfluence of the hemoglobin (hematocrit) reduction.