Early birds vs night owls: Pre-class activities

And are our natural sleep schedules predetermined at birth?
These nerve cells respond to light exposure coming in through your eyes to track the day-night cycle that dictates your body’s internal clock, or circadian rhythm. Everyone’s bodies are unique, so even two people with the same sleep schedule might have different experiences based on their circadian system’s hormonal quirks. But perhaps just as important as sleep hygiene is light hygiene.