Increase in cooperativity of oxygen binding as a factor related to high maximal oxygen uptake during physical effort.

In a group of trained, nonsmoking men, apparent haemoglobin oxygen affinity was assessed in vitro in the whole blood collected immediately before and after maximal physical effort. Measurements were performed using standard laboratory equipment. Maximal oxygen uptake (V O2 max) has been monitored during maximal physical effort. Increase in app Hb-oxygen affinity after exercise was found by measurements of p25 and by differences between plots of correlations between V O2 max and resting and post-exercise parameters of Hb-oxygen binding. Significant correlations were found between preexercise n50 and VO2 max (r = -0.59) and between post-exercise log P50 and V O2 max (r = 0.6). Exercise-induced increase in Hb-oxygen affinity and in cooperativity of Hb-O2 binding were found to be higher in persons with higher values of VO2 max.