1. From the Bioengineering and Chronobiology Laboratories (R.C.H., D.E.A., J.R.F., A.M.), University of Vigo, Campus Universitario, Vigo, Spain; and Hypertension and Vascular Risk Unit (C.C., J.E.L., M.J.D., M.C.), Hospital Clínico Universitario, Santiago de Compostela, Spain.