More and more people spend their time in front of a computer screen, often at night while there are no other light sources around. A large number of these monitors have LED (Light Emitting Diode) backlights, which strongly emitt light at a wavelength of around 464 nanometres. This corresponds to blue light.
Light at those wavelengths influences the concentrations of the sleep hormone melatonin, and thereby can influence productivity and cognitive ability late at night.
Now scientists from the University of Basel have shown that test subjects in front of LED screens were less sleepy than those that were not. In comparison the subjects aged from 19 - 34, showed up to 20% faster reaction times. They were both objectively and subjectively more awake and also performed better in a memory test.
This works by supressing the sleep hormone melatonin for longer periods of time, meaning that they could concentrate longer.
The researchers have suggested developing monitors that can be programmed to emitt a number of wavelengths, so that the sleeping pattern is not disturbed when using computers in the evening.