Here is a great article on circadian rhythms and the science behind Kulala. (Image from article)

From the article:

Highlights:
→ Maintaining consistent and healthy circadian rhythms may help improve overall health 
and prevent chronic diseases.
→ Think beyond sleep: Circadian rhythms are influenced by eating, exercise, and other factors.
→ Learn the idiosyncrasies of your own rhythms, your “chronotype,” then adapt them to the best 
practices indicated by scientific research.