The effect of mental arithmetic on the blood flow through normal, sympathectomized and hyperhidrotic hands

Abramson & Ferris (1940) studied the effect of a short period of mental arithmetic on the volume of the hand and on the rate of its blood flow. They found a decrease in both volume and blood flow. Their subject did a sum which took between 12 and 19 sec to answer. The aim of the present work was to study the changes in hand blood flow during 10 min mental arithmetic, a longer test than that used by Abramson & Ferris. The results show that under the conditions of our experiments the initial vasoconstriction, if present, was usually only transient. Furthermore, an unexpected result was observed in the hands of some hyperhidrotic subjects, namely, a marked vasodilatation.