Bergen Stress and Sleep Group, BSSG

Consequences of night shift simulation on waking performance, sleep, circadian rhythmicity and brain function

collage av mennesker som jobber med datamaskin i lys med forskjellige farger og rotter som jobber nattskift og har blåt lys i rommet

Main content

We live in a 24h society where a range of services are required around the clock. As a result, millions of people worldwide are working at times when the body is tuned to sleep. Night shift work is associated with impaired waking function and increased risk of accidents during work hours. There are also negative health effects associated with night shift work, such as sleep problems, metabolic syndrome, cardiac disease and certain types of cancer.

The Bergen Stress and Sleep group and collaborators work translationally to study the effects of simulated night shift work on waking performance, sleep, circadian rhythmicity, metabolic measures and molecular markers of brain function. We also investigate ways to counter these negative effects, particularly how light of different intensity and color quality impact on waking performance and brain function.

The project includes both human and animal experiments. We aim to find out how simulated night shift work and different light conditions affect:

  • Sleep quality and length
  • Waking function (alertness and cognitive performance)
  • Circadian rhythmicity
  • Brain function and protein synthesis
  • Energy intake and expenditure


Publications from this project

Role of nocturnal light intensity on adaptation to three consecutive night shifts: a counterbalanced crossover study. Sunde E, Mrdalj J, Pedersen T, Thun E, Bjorvatn B, Grønli J, Harris A, Waage S, Pallesen S, 2020, Occup Environ Med [Epub ahead of print]

Can night shift workers benefit from light exposure?  Grønli J, Mrdalj J. The Journal of physiology, 2018, 596(12):2269-2270.

No Escaping the Rat Race: Simulated Night Shift Work Alters the Time-of-Day Variation in BMAL1 Translational Activity in the Prefrontal Cortex. Marti AR, Patil S, Mrdalj J, Meerlo P, Skrede S, Pallesen S, Pedersen TT, Bramham CR, Grønli J. Frontiers in Neural Circuits, 2017 11(70). doi: 10.3389/fncir.2017.00070.

A rodent model of night-shift work induces short-term and enduring sleep and electroencephalographic disturbances. Grønli J, Meerlo P, Pedersen TT, Pallesen S, Skrede S, Marti AR, Wisor JP, Murison R, Henriksen TEG, Rempe MJ, Mrdalj J. J Biol Rhythm, 2017 Feb;32(1):48-63. doi: 10.1177/0748730416675460.

Shift in food intake and changes in metabolic regulation and gene expression during simulated night-shift work. A rat model. Marti AR, Meerlo P, Grønli J, van Hasselt SJ, Mrdalj J, Pallesen S, Pedersen TT, Henriksen TEG, Skrede S. Nutrients, 2016 Nov 8;8(11). doi:10.3390/nu8110712

Mathematical modeling of sleep state dynamics in a rodent model of shift work Rempe MJ, Grønli J, Pedersen TT, Mrdalj J, Marti AR, Meerlo P, Wisor JP. Neurobiology of Sleep and Circadian Rhythms, 2018, 5:37-51

Doctoral degrees

Andrea Rørvik Marti. Shift work, circadian rhythms, and the brain. Identifying biological mechanisms underlying the metabolic and cognitive consequences of work timing, using a rat model. 

Erlend Sunde. Effects of light interventions for adaptation to night work. Simulated night work experiments. 


Master degrees


Maiken Birkelid. Modeling night shift work and gastrointestinal function

Øystein Holmelid. Simulated Night Work, Sleep-Wake Changes and Markers of Brain Plasticity

Josien Janssen. Effects of simulated night shift work on circadian rhythmicity of body temperature

Andrea Rørvik Marti. Circadian and metabolic consequences of shift work -a rat model

Torhild Pedersen. Night work and disturbances in sleep- an animal model