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Dautovich ND, Schreiber DR, Imel JL, Tighe CA, Shoji KD, Cyrus J, Bryant N, Lisech A, O'Brien C, Dzierzewski JM. A systematic review of the amount and timing of light in association with objective and subjective sleep outcomes in community-dwelling adults. Sleep Health 2019; 5:31-48. [PMID: 30670164 PMCID: PMC6814154 DOI: 10.1016/j.sleh.2018.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 09/12/2018] [Accepted: 09/17/2018] [Indexed: 12/01/2022]
Abstract
Light is considered the dominant environmental cue, or zeitgeber, influencing the sleep-wake cycle. Despite recognizing the importance of light for our well-being, less is known about the specific conditions under which light is optimally associated with better sleep. Therefore, a systematic review was conducted to examine the association between the amount and timing of light exposure in relation to sleep outcomes in healthy, community-dwelling adults. A systematic search was conducted of four databases from database inception to June 2016. In total, 45 studies met the review eligibility criteria with generally high study quality excepting for the specification of eligibility criteria and the justification of sample size. The majority of studies involved experimental manipulation of light (n = 32) vs observational designs (n = 13). Broad trends emerged suggesting that (1) bright light (>1000 lux) has positive implications for objectively assessed sleep outcomes compared to dim (<100 lux) and moderate light (100-1000 lux) and (2) bright light (>1000 lux) has positive implications for subjectively assessed sleep outcomes compared to moderate light (100-1000 lux). Effects due to the amount of light are moderated by the timing of light exposure such that, for objectively assessed sleep outcomes, brighter morning and evening light exposure are consistent with a shift in the timing of the sleep period to earlier and later in the day, respectively. For subjectively assessed sleep outcomes, brighter light delivered in the morning was associated with self-reported sleep improvements and brighter evening light exposure was associated with worse self-reported sleep.
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Affiliation(s)
- Natalie D Dautovich
- Psychology Department, Virginia Commonwealth University, 800 W Franklin St, Room 203, PO Box 842018, Richmond, VA 23284-2018.
| | - Dana R Schreiber
- Psychology Department, Virginia Commonwealth University, 806 W Franklin St, PO Box 842018, Richmond, VA 23284-2018
| | - Janna L Imel
- Psychology Department, Virginia Commonwealth University, 806 W Franklin St, PO Box 842018, Richmond, VA 23284-2018
| | - Caitlan A Tighe
- Department of Psychology, University of Alabama, Box 870348, The University of Alabama, Tuscaloosa, AL 35487-0348
| | - Kristy D Shoji
- South Texas Veterans Healthcare System, 7400 Merton Minter, San Antonio, TX 78229
| | - John Cyrus
- Tompkins-McCaw Library, Virginia Commonwealth University, 509 N 12th St, Box 980582, Richmond, VA 23298-0582
| | - Nita Bryant
- James Branch Cabell Library, Virginia Commonwealth University, 901 Park Ave, Box 842033,Richmond, VA 23284-2033
| | - Andrew Lisech
- Psychology Department, Virginia Commonwealth University, 806 W Franklin St, PO Box 842018, Richmond, VA 23284-2018
| | - Chris O'Brien
- Psychology Department, Chatham University, Woodland Rd, Pittsburgh, PA 15232
| | - Joseph M Dzierzewski
- Psychology Department, Virginia Commonwealth University, 806 W Franklin St, PO Box 842018, Richmond, VA 23284-2018
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