Blue light from your phone or computer in the evening interferes with sleep as well.......
The system that allows our body to regulate a certain number of vital functions over a period of about 24 hours is called the body clock (or circadian rhythm). Located deep within the brain, it consists of 20,000 neurons whose pulsatile activity controls the sleep/wake cycle, body temperature, heart rate, the release of hormones, etc. The cycle determined by the internal clock lasts spontaneously between 23.5 to 24.5 hours, depending on the individual. In order to function correctly, it refers to the signals that it receives from the external world and that it interprets as indicators for the purpose of constantly resynchronising itself every 24 hours.
This is why the intake of food, physical exercise and the external temperature, for example, are said to be 'time setters'. The most important 'time setter', however, is light. After inappropriate exposure to light, your entire body clock is thrown out of order with consequences for cognitive functions, sleep, alertness, memory, cardiovascular functions, etc.
On a general level, the study shows that an optimised light spectrum enriched with short wavelengths (blue) can enable the circadian system to synchronise correctly and non-visual functions to be activated in extreme situations where sunlight is not available for long stretches of time.