When you start to get enough sleep, it's normal to become biphasic. That is, wake up in the night and go back to sleep. https://en.wikipedia.org/wiki/Biphasic_a

When you start to get enough sleep, it's normal to become biphasic. That is, wake up in the night and go back to sleep. https://en.wikipedia.org/wiki/Biphasic_and_polyphasic_sleep https://en.wikipedia.org/wiki/Biphasic_and_polyphasic_sleep