“Night owls” are disadvantaged when it comes to the 9-to-5 workday. A new randomized controlled trial shows that “night owl” chronotypes may be able to shift their circadian rhythms by an average of two hours, and this was associated with improvements in mental wellbeing and perceived sleepiness.

The title of the post is a copy and paste from the first two paragraphs of the linked academic press release here:

In February, scientists revealed hard evidence that night owls have a biological handicapped when it comes to the 9-to-5 workday. Fortunately, research published Sunday in Sleep Medicine offers a way for night owls can fight back against their natural circadian rhythms, making mornings a lot more tolerable.

A randomized controlled trial conducted by scientists at the University of Birmingham in England and Monash University in Australia showed that it’s possible for night owls to hack their own deep-seated biological rhythms. By adhering to the routine designed by these scientists, 22 “night owls” were able to shift their internal rhythms by an average of two hours.

Journal Reference:

Elise R. Facer-Childs, Benita Middleton, Debra J. Skene, Andrew P. Bagshaw,

Resetting the late timing of ‘night owls’ has a positive impact on mental health and performance,

Sleep Medicine, 2019, ISSN 1389-9457,

Link: http://www.sciencedirect.com/science/article/pii/S1389945719301388

DOI: https://doi.org/10.1016/j.sleep.2019.05.001.


Here we took a group of ‘night owls’ (i.e. people with extreme late sleeping and waking patterns) and attempted to shift their habitual late timings earlier in a real-world setting using simple, practical non-pharmacological interventions. We show that by using this intervention we can:

• Achieve a phase advance of around two hours

• Decrease self-reported ratings of depression and stress

• Reduce sleepiness in the morning

• Significantly improve simple indices of cognitive and physical performance


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’ e.g. 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. 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. 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. Importantly, 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. 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.

Leave a Reply

Your email address will not be published. Required fields are marked *