At the Centre for Chronobiology of the University of Basel, [Dr Christine] investigates the effects of light on humans and is the first author of a study investigating the effects of different light colors on the internal clock and sleep. The team of researchers from the University of Basel and the TUM has now published its findings in the journal Nature Human Behaviour.

Night mode on screens—useful or not?
We often hear that the short-wavelength component of light from smartphone and tablet screens affects biological rhythms and sleep. The recommendation is therefore to put your mobile phone away early in the evening or at least use the night shift mode, which reduces the short-wavelength light proportions and looks slightly yellowish. Dr. Blume confirms this. However, the yellowish color adjustment is a by-product that could be avoided.

"Technologically, it is possible to reduce the short-wavelength proportions even without color adjustment of the display; however, this has not yet been implemented in commercial mobile phone displays," says the sleep researcher.