Format

Send to

Choose Destination
Sleep Med. 2019 May 10. pii: S1389-9457(19)30138-8. doi: 10.1016/j.sleep.2019.05.001. [Epub ahead of print]

Resetting the late timing of 'night owls' has a positive impact on mental health and performance.

Author information

1
School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK; Centre for Human Brain Health, University of Birmingham, Birmingham, B15 2TT, UK; School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK. Electronic address: Elise.Facer-Childs@monash.edu.
2
Faculty of Health & Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
3
Centre for Human Brain Health, University of Birmingham, Birmingham, B15 2TT, UK; School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK.

Abstract

BACKGROUND:

There is conflict between living according to our endogenous biological rhythms and our external environment, with disruptions resulting in negative consequences to health and performance. This is often documented in shift work and jet lag, but 'societal norms' (eg, typical working hours) can create profound issues for 'night owls', people whose internal biological timing predisposes them to follow an unusually late sleep-wake cycle. Night owls have also been associated with health issues, mood disturbances, poorer performance and increased mortality rates.

METHODS:

This study used a randomized control trial design aimed to shift the late timing of night owls to an earlier time (phase advance), using non-pharmacological, practical interventions in a real-world setting. These interventions targeted light exposure (through earlier wake up/sleep times), fixed meals times, caffeine intake and exercise.

RESULTS:

Overall, participants demonstrated a significant advance of ∼2 h in sleep/wake timings as measured by actigraphy and circadian phase markers (dim light melatonin onset and peak time of the cortisol awakening response), whilst having no adverse effect on sleep duration. Notably, the phase advance was accompanied by significant improvements to self-reported depression and stress, as well as improved cognitive (reaction time) and physical (grip strength) performance measures during the typical 'suboptimal' morning hours.

CONCLUSIONS:

Our findings propose a novel strategy for shifting clock timing towards a pattern that is more aligned to societal demands that could significantly improve elements of performance, mental health and sleep timing in the real world.

KEYWORDS:

chronotype; circadian phase markers; depression; non-pharmacological interventions; performance; stress

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center