Evening chronotype, insufficient weekday sleep, and weekday-weekend gap in sleep times: What is really to blame for a reduction in self-perceived health among university students?

ABSTRACT

The association of insufficient sleep with reduced self-perceived health was previously well established. Moreover, it was sometimes shown that the indicators of poorer health were significantly related to chronotype and weekday-weekend gaps in sleep timing and duration. It remains to be elucidated, however, whether chronotype and these gaps can contribute to the reduced health self-ratings independently from shortened sleep duration or, alternatively, their relationship with health can be simply explained by their association with insufficient sleep on weekdays. In an online survey, we tested whether the self-rated health of university students can be predicted by several individual characteristics of the sleep-wake cycles, such as chronotype, weekday and weekend sleep times, weekday-weekend gap in sleep times, sleepability and wakeability at different times of the day, etc. Responses to a question about general health and to items of several questionnaires for chronobiological assessment were collected from smartphones of 1582 university students (mean age ± standard deviation was 19.5 ± 1.7 y). The results of regression analyses suggested that lower odds of having good self-rated health were significantly associated with an earlier weekday risetime, a later weekday bedtime, and, consequently, a shorter weekday time in bed. After accounting for weekday sleep, self-rated health showed significant association with neither chronotype nor weekday-weekend differences in sleep duration and timing. Besides, the adverse health effects of reduced weekday sleep were independent from the significant adverse effects of several other individual sleep-wake characteristics including poorer nighttime sleepability and lower daytime wakeability. We concluded that university students perceive the negative health impacts of losing sleep by waking up early on weekdays irrespective of their night sleep quality and daytime level of alertness. Their chronotype and weekday-weekend difference in sleep times might not be among significant contributors to this perception. It is of practical importance to consider the reduction of weekday sleep losses among the interventions aimed at preventing sleep and health problems.

KEYWORDS:

• Sleep curtailment
• sleep duration
• sleep timing
• self-rated health
• chronotype

Acknowledgments

The North-Caucasus Federal University provided technical support to AAP. We are thankful to Ana K. Jones who devoted her time to editing this article.

Author contributions

Conceptualization AAP; Funding acquisition AAP, DSS, and VBD; Data curation DSS, ZVB, ENY, YPS, VIT, EAT, MML, ZNL, EOG, and NVL, Resources AAP, DSS, and VBD; Project administration AAP, DSS, and VBD; Supervision AAP and VBD; Software AAP, DSS, and AAP; Investigation AAP, DSS, and ANP; Methodology AAP, DSS, and ANP; Validation AAP; Visualization AAP and DSS; Writing – review & editing AAP, DSS; DSS, ZVB, ENY, YPS, VIT, EAT, MML, ZNL, EOG, ANP, and VBD.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and material

The survey dataset is available on reasonable request to the corresponding author.

Ethical approval

All procedures performed in this survey of human participants were in accordance with the ethical standards of the 2022b Helsinki Declaration and its later amendments and in accordance with the ethical standards of the institutional research committee (the Ethics Committees of the Institute of Higher Nervous Activity and Neurophysiology approved the experimental protocol in June 2019, Approval#12402-02-7112).

Informed consent statement

Informed consent was obtained from each of the study participants in the form of response “Yes” to the question of the survey saying “I give informed consent to voluntarily participate in this online survey of sleep-wake behavior and habits” (see the method section).

Additional information

Funding

VBD was funded by the Russian Science Foundation [grant # 22-28-01769].