KENNEY, W. L. and J. M. JOHNSON. Control of skin blood How during exercise.Med. Sci. Sports. Exerc., Vol. 24, No. 3, pp. 303–312, 1992. When body temperature rises, skin blood flow (SkBF) increases to effect transfer of metabolic heat from the core to the skin. This convective heat transfer is never more important than during dynamic exercise. Control of SkBF involves a complex interaction of regulatory systems (body temperature, blood pressure, metabolism, etc.) and efferent mechanisms (passive withdrawal of constrictor tone, reflex vasoconstriction, active vasodilation). The purpose of this paper is to provide an updated review of this complex control system—control that allows for maintenance of blood pressure and perfusion of active muscle without adverse impact on thermoregulation. Also discussed are vasomotor mechanisms, various components of exercise that are important in the control of SkBF (e.g., intensity, posture, and duration of exercise), and the influences of such factors as blood volume and tonicity, aerobic fitness and heat acclimation, and age.