1. Escuela de Kinesiología, Facultad de Salud, Universidad Santo Tomás, Los Angeles 4440000, Chile
2. Centro de Enfermedades Respiratorias, Clínica Las Condes, Facultad de Medicina Universidad Finis Terrae, Santiago 7591047, Chile
3. Universidad Favarolo, Buenos Aires C1079ABE, Argentina
4. Universidad Catolica Argentina, Buenos Aires C1107AFB, Argentina
5. Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, University of Concepción, Concepción 4070112, Chile
6. Division of Sleep Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, USA