[Blood histamine during submaximal muscular work].

Blood histamine was measured in 20 healthy males before and after performance of rectangular type submaximal work. The results show that following muscular work there is an increase in the blood concentration of the substance in all the subjects examined, the average increase being 33% although variations from one subject to another were considerable. It is hypothesized that the increase in the histamine level can be explained by admitting an increase in histidine-decarboxylase activity at tissue level with consequent synthesis of a greater quantity of histamine.