Circadian rhythms are primary drivers for various hormones in your body (e.g. melatonin, body temps, cortisol levels). These rhythms are tightly tied to extern

Circadian rhythms are primary drivers for various hormones in your body (e.g. melatonin, body temps, cortisol levels). These rhythms are tightly tied to external/evolutionary triggers. Yours body resets its internal clock* based on external cues, the strongest of which are eating and exposure to daylight. Since we don't have little clocks saying it's 6:05 in our heads, the body uses blue light hitting the retinas as a proxy. It's the knock-on-effects of having misaligned cortisol levels (which further induce lack of sleep / stress) that are the problem, not the blue light. *The natural rhythm of each individual differs, hence the cave/space experiments where some people naturally fall into a ~25h cycle [due to lack of external cues]).