https://doi.org/10.5664/jcsm.8780 SPECIAL ARTICLES Daylight saving time: an American Academy of Sleep Medicine position statement Muhammad Adeel Rishi, MD1;OmerAhmed,MD2; Jairo H. Barrantes Perez, MD3; Michael Berneking, MD4; Joseph Dombrowsky, MD5; Erin E. Flynn-Evans, PhD, MPH6; Vicente Santiago, MD7; Shannon S. Sullivan, MD8,9; Raghu Upender, MD10;KinYuen,MD,MS11; Fariha Abbasi-Feinberg, MD12; R. Nisha Aurora, MD, MHS13; Kelly A. Carden, MD, MBA14; Douglas B. Kirsch, MD15; David A. Kristo, MD16; Raman K. Malhotra, MD17;JenniferL.Martin,PhD18,19; Eric J. Olson, MD20; Kannan Ramar, MD20; Carol L. Rosen, MD21; James A. Rowley, MD22; Anita V. Shelgikar, MD, MHPE23; Indira Gurubhagavatula, MD, MPH24,25 1Department of Pulmonology, Critical Care and Sleep Medicine, Mayo Clinic, Eau Claire, Wisconsin; 2Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York; 3Baylor College of Medicine, Houston, Texas; 4Concentra, Inc., Grand Rapids, Michigan; 58 Hour Sleep Clinic, El Paso, Texas; 6Fatigue Countermeasures Laboratory, Human Systems Integration Division, NASA Ames Research Center, Moffett Field, California; 7Sleep Medicine, The Permanente Medical Group, Manteca, California; 8Department of Pediatrics, Division of Pulmonary, Asthma & Sleep Medicine, Stanford University School of Medicine, Palo Alto, California; 9Eval Research Institute, Palo Alto, California; 10Department of Neurology, Division of Sleep Medicine, Vanderbilt Medical Center, Nashville, Tennessee; 11Sleep Disorders Center, UCSF Health, San Francisco, California; 12Sleep Medicine, Millennium Physician Group, Fort Myers, Florida; 13Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey; 14Saint Thomas Medical Partners - Sleep Specialists, Nashville, Tennessee; 15Sleep Medicine, Atrium Health, Charlotte, North Carolina; 16University of Pittsburgh, Pittsburgh, Pennsylvania; 17Sleep Medicine Center, Washington University School of Medicine, St. Louis, Missouri; 18Veteran Affairs GreaterLos Angeles HealthcareSystem, North Hills, California; 19David Geffen School of Medicine at the University of California, Los Angeles, California; 20Division of Pulmonary and Critical Care Medicine, Center for Sleep Medicine, Mayo Clinic, Rochester, Minnesota; 21Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio; 22Wayne State University, Detroit, Michigan; 23University of Michigan Sleep Disorders Center, University of Michigan, Ann Arbor, Michigan; 24Division of Sleep Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; 25Corporal Michael Crescenz Virginia Medical Center, Philadelphia, Pennsylvania The last several years have seen intense debate about the issue of transitioning between standard and daylight saving time. In the United States, the annual advance to daylight saving time in spring, and fall back to standard time in autumn, is required by law (although some exceptions are allowed under the statute). An abundance of accumulated evidence indicates that the acute transition from standard time to daylight saving time incurs significant public health and safety risks, including increased risk of adverse cardiovascular events, mood disorders, and motor vehicle crashes. Although chronic effects of remaining in daylight saving time year-round have not been well studied, daylight saving time is less aligned with human circadian biology—which, due to the impacts of the delayed natural light/dark cycle on human activity, could result in circadian misalignment, which has been associated in some studies with increased cardiovascular disease risk, metabolic syndrome and other health risks. It is, therefore, the position of the American Academy of Sleep Medicine that these seasonal time changes should be abolished in favor of a fixed, national, year-round standard time. Citation: Rishi MA, Ahmed O, Barrantes Perez JH, et al. Daylight saving time: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2020;16(10):1781–1784. INTRODUCTION only acute personal disruptions, but significant public health and safety risks.2 The American Academy of Sleep Medicine (AASM) is a pro- fessional society that advances sleep care and enhances sleep health to improve lives. The AASM advocates for policies that BACKGROUND recognize that sleep is essential to health. The period of the year between spring and fall, when clocks Scientific, public and political debate about DST abounds. In in most parts of the United States (U.S.) are set one hour ahead response, the European Biological Rhythms Society (EBRS), of standard time, is called daylight saving time (DST), and European Sleep Research Society (ESRS), and Society for its beginning and ending dates and times are set by federal Research on Biological Rhythms (SRBR) published a joint law (the second Sunday in March at 2:00 AM and the first statement, declaring that permanent standard time is the best Sunday in November at 2:00 AM, respectively), while the option for public health.3 In fact, the following year the SRBR remaining period between fall and spring of the following year published the position paper, “Why Should We Abolish Day- is called standard time.1 light Saving Time?”2 Also, the European Parliament voted to The light/dark cycle is key in circadian entrainment. The end the mandatory DST change by 2021.4 acute alterations in timing due to transitions to and from DST In the U.S., the Congressional Research Service has iden- contribute to misalignment between the circadian biological tified dozens of states that have introduced legislation that clock and the light/dark cycle (or photoperiod), resulting in not would support changes to the observance of DST.5 While Downloaded from jcsm.aasm.org by 163.116.137.118 on October 27, 2020. For personal use only. No other uses without permission. Copyright 2020 American Academy of Sleep Medicine. All rights reserved. Journal of Clinical Sleep Medicine, Vol. 16, No. 101781 October 15, 2020 MA Rishi, O Ahmed, JH Barrantes Perez, et al. Position statement: daylight saving time broad support exists for the elimination of the spring and fall Although most acute health-related effects are noted only time changes, proposed solutions are conflicting: Some states when transitioning from standard time to DST, transitions both have introduced legislation proposing variations of permanent into and out of DST have been associated with sleep DST, and a nearly equal number of states have introduced disruption,13 mood disturbances and suicide.18 Trafficaccidents legislation to establish permanent standard time. Although increase in the first few days after the change from standard U.S. statute allows state-level exemption from DST,1 and the time to DST,19 with an increase in fatal crashes of up to 6% in exemption was claimed by Hawaii and Arizona, moving to the United States.20 permanent DST nationwide would require legislative approval On the Monday after the transition to DST, volatility in stock by the U.S. Congress. markets in the U.S. has been observed.21 While reasons for this are not entirely clear, proposed mechanisms include the impact of sleep deprivation on frontal lobe functioning, which may result in impaired judgement and decision-making capacity.22 POSITION It is the position of the AASM that the U.S. should eliminate Chronic effects of DST seasonal time changes in favor of a national, fixed, year- There is little direct evidence regarding the chronic effects of round time. Current evidence best supports the adoption of DST. Most studies have either been retrospective or have year-round standard time, which aligns best with human addressed the issue indirectly. DST has been associated with a 23 circadian biology and provides distinct benefits for public decrease in crime rate, and it may be associated with a modest health and safety. overall decrease in risk of motor vehicle crashes, possibly due to hours of daylight lasting longer in the evening when most accidents occur, along with other, less obvious reasons.5 However, when temporary, year-round DST was adopted in response to an DISCUSSION Organization of the Petroleum Exporting Countries (OPEC) oil embargo, increased fatalities among school-aged children in Light is the most powerful exogenous zeitgeber,orcue,tothe the morning were noted between January and April. These 2 regulation of the endogenous circadian rhythm. The human findings may be due to darkness lasting longer in the morning circadian phase responds to light in a predictable fashion, by when children are traveling to school, while other factors delaying phase (with endogenous biological sleep onset and also may be at play.24 offset preferences occurring at a later clock time) in the setting DST is less well-aligned with intrinsic human circadian 6 of both morning darkness and evening light. DST, therefore, physiology, and it disrupts the natural seasonal adjustment induces phase delay by increasing the exposure to both morning of the human clock due to the effect of late-evening light on 2 darkness and evening light. the circadian rhythm.25 DST results in more darkness in the The recommendation in support of permanent standard time morning hours, and more light in the evening hours. Both isbasedonareviewofexistingliterature that describes the early morning darkness and light in the evening have a similar acute, adverse effects of switching between standard time and effect on circadian phase, causing