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