Studying the reaction of blood stroke volume of the children of the 1st-4th forms during oral replies revealed that the pupils who systematically do muscle training have significantly reduced stroke volume reaction during oral lessons by the 4th form. Therefore, systematic muscle training contributes to less extensive changes in stroke volume during oral answers of the primary school pupils. The children leading sedentary lifestyle have the reaction of blood stroke volume during oral replies increasing with age. Moreover, the children referred to the group of intensified physical activity, at the 4th form have stroke volume reduction to the initial values after the oral answers. It is going on much faster than within children from the test group.