It's 2 a.m. The house is quiet, cloaked in the stillness of the night. Then, a shuffle. A door creaks. A child walks down the hallway, eyes wide open but fast asleep. Elsewhere, someone mumbles ...

When you fall asleep each night, your body goes into restore mode, repairing tissues and balancing your immune system. Your brain is also pretty active, clearing out waste while consolidating episodes ...