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Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing

Andrew J. K. Phillips, William M. Clerx, Conor S. O’Brien, Akane Sano, Laura K. Barger, Rosalind W. Picard +3 more
Scientific Reports2017CC BY 4.0
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Published articlePublication date: Jun 12, 2017Added to atlas: Oct 15, 2026Source
Citations579Crossref referencesChecked Oct 16, 2026
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Activity counts measure attention, not model quality. Missing counts are unknown. Publication status follows the linked source; a listed venue alone does not confirm peer review.

Phillips and colleagues followed 61 undergraduates for 30 days with sleep diaries and introduced the Sleep Regularity Index (SRI), a metric of day-to-day consistency in sleep/wake timing. Compared with regular sleepers, irregular sleepers had dim-light melatonin onset about 2.5 hours later, a later-peaking sleep propensity rhythm and lower-amplitude light exposure measured by wrist-worn photometry. SRI correlated positively with academic performance (r = 0.37), and circadian modelling suggested the timing differences were driven mainly by light exposure patterns.

  • Result: DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p < 0.003); the daily sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p < 0.005); and light rhythms had lower amplitude (102 ± 19 lux vs. 179 ± 29 lux; p < 0.005) in Irregular…
  • Result: A positive correlation (r = 0.37; p < 0.004) between academic performance and SRI was observed.
At a glance
Venue
Scientific Reports
Published
2017
DOI
10.1038/s41598-017-03171-4 (opens in a new tab)
arXiv
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PMID
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Licence
CC BY 4.0 (opens in a new tab)
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Code
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Added
Oct 15, 2026

Abstract

The association of irregular sleep schedules with circadian timing and academic performance has not been systematically examined. We studied 61 undergraduates for 30 days using sleep diaries, and quantified sleep regularity using a novel metric, the sleep regularity index (SRI). In the most and least regular quintiles, circadian phase and light exposure were assessed using salivary dim-light melatonin onset (DLMO) and wrist-worn photometry, respectively. DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p < 0.003); the daily sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p < 0.005); and light rhythms had lower amplitude (102 ± 19 lux vs. 179 ± 29 lux; p < 0.005) in Irregular compared to Regular sleepers. A mathematical model of the circadian pacemaker and its response to light was used to demonstrate that Irregular vs. Regular group differences in circadian timing were likely primarily due to their different patterns of light exposure. A positive correlation (r = 0.37; p < 0.004) between academic performance and SRI was observed. These findings show that irregular sleep and light exposure patterns in college students are associated with delayed circadian rhythms and lower academic performance. Moreover, the modeling results reveal that light-based interventions may be therapeutically effective in improving sleep regularity in this population.

Verbatim fromthe publisher's DOI record· Publisher licence: https://creativecommons.org/licenses/by/4.0

Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing: ChatPPG research summary card

Key results

0.37
R
SRI correlated positively with academic performance (r = 0.37), and circadian modelling suggested the timing differences were driven main…

How it works

How Method works: Setup → Method → ResultMethod: Method. Result: Result (DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p < 0.003); the daily sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p < 0.005); and light rhythms had lower amplitude (102 ± 19 lux vs. 179 ± 29 lux; p < 0.005) in Irregular…); Result (A positive correlation (r = 0.37; p < 0.004) between academic performance and SRI was observed.).MethodMethodResultResult: DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p < 0.003); the daily sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p < 0.005); and light rhythms had lower amplitude (102 ± 19 lux vs. 179 ± 29 lux; p < 0.005) in Irregular…ResultDLMO occurred later (00:08 ± 1:54 vs.…Result: A positive correlation (r = 0.37; p < 0.004) between academic performance and SRI was observed.ResultA positive correlation (r = 0.37; p <…

Cite

@article{phillipssleepregularityi2017,
  title = {{Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing}},
  author = {Andrew J. K. Phillips and William M. Clerx and Conor S. O’Brien and Akane Sano and Laura K. Barger and Rosalind W. Picard and Steven W. Lockley and Elizabeth B. Klerman and Charles A. Czeisler},
  year = {2017},
  journal = {Scientific Reports},
  doi = {10.1038/s41598-017-03171-4}
}

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