That’s right. Dark. Your body needs it too.
Being exposed to regular patterns of light and dark regulates our circadian rhythm. Disruption of this rhythm may increase the risk of developing some health conditions including obesity, diabetes and breast cancer
Light regulates our sleep and wake patterns
The physiological processes that control the daily cycle of sleep and wake, hunger, activity levels, body temperature, melatonin level in the blood, and many other physiological traits are called the endogenous circadian rhythm.
Read more at The Conversation