So in the quest for m0ar Healthy..
Just read an article on bi-modal sleep.
In earlier days Pre-electric/gas indoor lighting,   people slept quite early, because there's really nothing to do..
What would happen is,  
They would sleep shortly after sundown, 
wake up for 2-4 hours during the early morning,  
Do , reading/prayer/study
Then go back to sleep until sunrise.. 
There is no difference in the quantity of Total Hours Slept..  
The practice is well documented and endemic during early history.