Forearm blood flow and metabolism during stylized and unstylized states of decreased activation.

We have measured forearm oxygen consumption and blood flow changes during two wakeful rest behaviors. We have observed acute reduction of forearm respiration (28%) during an acute stylized rest state (TM) and a nonsignificant small decline (11%) during unstylized ordinary eyes-closed rest. These changes were not associated with significant change of forearm blood flow or glycolytic metabolism. Hence, forearm oxygen consumption decline was due almost solely to decreased rate of oxygen extraction. Small variation of forearm blood flow implies that little of the previous findings of increased nonrenal, nonhepatic circulation during TM or increased nonrenal circulation during ordinary rest can be accounted for by altered muscle blood flow, which therefore is consistent with possible increased cerebral blood flow. However, reduced muscle metabolism was a likely contributor to the forearm metabolic decline. The lack of coupling between metabolic and blood flow changes during TM indicates limitation of obligatory coupling between cardiovascular and metabolic function in the rest state of TM.