DAYLIGHT MAKES YOU AWAKE
Morning light brings the hormone production of melatonin to a standstill. The level of melatonin in the blood drops, causing our organism to switch from the basic mode of regeneration to that of activity at the start of the day. In order to carry out this process, we need a daylight-equivalent illuminance of at least 240 lux at the eye. If we disconnect ourselves from sufficient morning light, we do not run in sync with our natural environment.
This explains why children can hardly be awake at the beginning of the school day during the winter months. They are awakened in the dark, contrary to the natural course of the day. This phenomenon is a form of so-called “social jet lag“.