There is a very interesting book called "why we sleep" by Matthew Walker. It explains the relation between sleep and learning, memory as well as health.
Sleeping enough and regularly (time can vary from person to person in a range from 6 to 8 hours for the great majority of us) improves learning and memorization substantially and protects against illness. Our cells reorganize and refresh and do a clean up while we sleep.
Also, I believe that lack of sleep makes one unproductive and less creative if repeated over time...
It is so important to prioritize sleep, and to sleep in regular patterns in order to a have a long quality life...
How do you treat sleep? What are your routines that work?
Good night from Europe at 10.27 pm