Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, 3100 Marine Street, Boulder, CO 80309, USA. Research and Development, Colorado Sleep Institute, 4895 Riverbend Rd A, Boulder, CO 80301, USA. Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA. Department of Pediatrics, Children's Hospital Colorado Anschutz Medical Campus, 13123 East 16th Ave, Aurora, CO 80045, USA. Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, Aurora, CO 80045, USA. Geriatric Research, Education, and Clinical Center, VA Eastern Colorado Health Care System, 1700 N Wheeling St, Aurora, CO 80045, USA. Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, 3222 SW Research Drive, Portland, OR 97239 USA.