Based on existing knowledge, we hypothesize that when compared to long wavelength LWL illumination, short wavelength SWL illumination from computer screen will have a more damaging effect on melatonin (MLT) production and secretion, interfering body temperature regulation and affecting sleep quality, efficiency and sleep architecture. In addition, we hypothesized that intensity of the screen illumination will play another important factor on these outcomes, we assume that high intensity compared to low intensity will have more damaging effect on: melatonin, thermoregulation and sleep.