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Light Res Technol. 2019 May;51(3):373-383. doi: 10.1177/1477153517748189. Epub 2018 Jan 9.

Does the iPad Night Shift mode reduce melatonin suppression?

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Lighting Research Center, Rensselaer Polytechnic Institute, Troy, USA.


The increased use of self-luminous displays, especially in the evening prior to bedtime, has been associated with melatonin suppression, delayed sleep and sleep curtailment. The present study set out to investigate whether the Night Shift application provided by Apple Inc. for use on its portable electronic devices is effective for reducing acute melatonin suppression, a well-established marker of circadian phase. Participants experienced four experimental conditions: a dim light control, a high circadian stimulus true positive intervention and two Night Shift interventions delivering low and high correlated colour temperature light from the devices. Melatonin suppression did not significantly differ between the two Night Shift interventions, which indicates that changing the spectral composition of self-luminous displays without changing their brightness settings may be insufficient for preventing impacts on melatonin suppression.

[Available on 2020-05-01]

Conflict of interest statement

Declaration of conflicting interests The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

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