Declarations. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of Monash University Human Research Ethics Committee (Study #24036) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent: Informed consent was obtained electronically from all individual participants included in the study. Preprint information: A preprint of this manuscript has posted on medRxiv: medRxiv 2024.08.15.24312067; doi: https://doi.org/10.1101/2024.08.15.24312067 . Conflict of interest: MDW reports institutional support from the US Centers for Disease Control and Prevention, National Institutes of Occupational Safety and Health, and Delta Airlines; as well as consulting fees from the Fred Hutchinson Cancer Center and the University of Pittsburgh. LKB reports institutional support from the US Centers for Disease Control and Prevention, National Institutes of Occupational Safety and Health, Delta Airlines, and the Puget Sound Pilots; as well as honorariums from the National Institutes of Occupational Safety and Health, University of Arizona and University of British Columbia. MÉC reported personal fees from Vanda Pharmaceuticals Inc., research grants or gifts to Monash University from WHOOP, Inc., Hopelab, Inc., CDC Foundation, and the Centers for Disease Control and Prevention. SMWR reported receiving grants and personal fees from Cooperative Research Centre for Alertness, Safety, and Productivity, receiving grants and institutional consultancy fees from Teva Pharma Australia and institutional consultancy fees from Vanda Pharmaceuticals, Circadian Therapeutics, BHP Billiton, and Herbert Smith Freehills. SFQ has served as a consultant for Teledoc, Bryte Foundation, Jazz Pharmaceuticals, Summus, Apnimed, and Whispersom. RR reports personal fees from SleepCycle AB; Rituals Cosmetics BV; Sonesta Hotels International, LLC; Ouraring Ltd; AdventHealth; and With Deep, LLC. CAC serves as the incumbent of an endowed professorship provided to Harvard Medical School by Cephalon, Inc. and reports institutional support for a Quality Improvement Initiative from Delta Airlines and Puget Sound Pilots; education support to Harvard Medical School Division of Sleep Medicine and support to Brigham and Women’s Hospital from: Jazz Pharmaceuticals PLC, Inc, Philips Respironics, Inc., Optum, and ResMed, Inc.; research support to Brigham and Women’s Hospital from Axome Therapeutics, Inc., Dayzz Ltd., Peter Brown and Margaret Hamburg, Regeneron Pharmaceuticals, Sanofi SA, Casey Feldman Foundation, Summus, Inc., Takeda Pharmaceutical Co., LTD, Abbaszadeh Foundation, CDC Foundation; educational funding to the Sleep and Health Education Program of the Harvard Medical School Division of Sleep Medicine from ResMed, Inc., Teva Pharmaceuticals Industries, Ltd., and Vanda Pharmaceuticals; personal royalty payments on sales of the Actiwatch-2 and Actiwatch-Spectrum devices from Philips Respironics, Inc; personal consulting fees from Axome, Inc., Bryte Foundation, With Deep, Inc. and Vanda Pharmaceuticals; honoraria from the Associated Professional Sleep Societies, LLC for the Thomas Roth Lecture of Excellence at SLEEP 2022, from the Massachusetts Medical Society for a New England Journal of Medicine Perspective article, from the National Council for Mental Wellbeing, from the National Sleep Foundation for serving as chair of the Sleep Timing and Variability Consensus Panel, for lecture fees from Teva Pharma Australia PTY Ltd. and Emory University, and for serving as an advisory board member for the Institute of Digital Media and Child Development, the Klarman Family Foundation, and the UK Biotechnology and Biological Sciences Research Council. CAC has received personal fees for serving as an expert witness on a number of civil matters, criminal matters, and arbitration cases, including those involving the following commercial and government entities: Amtrak; Bombardier, Inc.; C&J Energy Services; Dallas Police Association; Delta Airlines/Comair; Enterprise Rent-A-Car; FedEx; Greyhound Lines, Inc./Motor Coach Industries/FirstGroup America; PAR Electrical Contractors, Inc.; Puget Sound Pilots; and the San Francisco Sheriff’s Department; Schlumberger Technology Corp.; Union Pacific Railroad; United Parcel Service; Vanda Pharmaceuticals. CAC has received travel support from the Stanley Ho Medical Development Foundation for travel to Macao and Hong Kong; equity interest in Vanda Pharmaceuticals, With Deep, Inc, and Signos, Inc.; and institutional educational gifts to Brigham and Women’s Hospital from Johnson & Johnson, Mary Ann and Stanley Snider via Combined Jewish Philanthropies, Alexandra Drane, DR Capital, Harmony Biosciences, LLC, San Francisco Bar Pilots, Whoop, Inc., Harmony Biosciences LLC, Eisai Co., LTD, Idorsia Pharmaceuticals LTD, Sleep Number Corp., Apnimed, Inc., Avadel Pharmaceuticals, Bryte Foundation, f.lux Software, LLC, Stuart F. and Diana L. Quan Charitable Fund. Dr Czeisler’s interests were reviewed and are managed by the Brigham and Women’s Hospital and Mass General Brigham in accordance with their conflict-of interest policies. No other disclosures were reported.