Ágnes Sűdy1, Krisztina Ella1, Krisztina Káldi1,2
1Department of Physiology, Semmelweis University, Budapest
2Department of Laboratory Medicine, Semmelweis University, Budapest
Social jetlag (SJL), the discrepancy between sleep timing on workdays and free days, affects the majority of the population and has been found to be associated with increased health risk and health-impairing behaviors. Our previous study showed the negative effect of SJL on the academic performance of university students. In our present study we focused on the effect of SJL on sleep quality and the autonomic nervous control during sleep in a sample of healthy young males (n=33, aged 20-26 years).
Participants have been assigned into two groups based on their sleep schedules, either with high or with average and low SJL. For the assessment of heart rate variability (HRV), a marker reflecting the activity of the autonomic nervous system, inter-beat-intervals were recorded during a workday and a weekend (free day) night using the Actiheart device (CamNtech Ltd.). To assess subjective sleep quality we used the Groningen sleep quality questionnaire.
Analyzing the HRV in the first six hours of sleep, we found no significant difference between the two nights in the group with low or average SJL. However, in the group with high SJL, HRV parameters calculated for the first two hours of sleep were higher on the weekend than on the weekday. Comparing the beginning of sleep for a duration equal to the difference of sleep onset between the two days, HRV parameters showed significant improvement from workday to weekend. Participants with high SJL reported a significantly worse sleep quality on workdays than on the weekend, whereas in the group with low or average SJL the two days did not differ.
Our results suggest that sleep timing forced by social constrains negatively impacts both subjective sleep quality and cardiac control during workday sleep.
Doctoral School: Doctoral School of Molecular Medicine
Program: Cellular and Molecular Physiology
Supervisor: Krisztina Kaldi
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