Sorry, poor English here. Some times, we tend to have devices inside the room which make subtle noises. Like a digital media player, for example, which tries to keep the HD spinning. It's a noise that you won't listen or pay attention to during the day, but at 2 A.M. your brain listens and process the noise.

The brain is an incredible machine. It tries to isolate all the known noises. So you have a phenomenon where people fall asleep while the usual noises can be captured by the ear, but when a new noise - as in unidentified - jumps in, you suddenly wake up.

If you can keep all these noises to a minimum, by switching off (not off mode, really off) such devices, will enhance your sleep quality. Keeps the brain less busy.

Also note that digital devices (especially routers and digital players) raise the room temperature by at least a couple of Celsius degrees, sometimes more[1]. Ideally, no working device should be on the bedroom while you're sleeping.

[1] I had a Dreambox-500 PVR in my bedroom. Apart from the incredible noise, when it was running during the day, the temperature was at least 6 Celsius higher, with no windows/doors open.

It probably has to do with waking up at 13 AM......

or eating dinner at 8-9 AM ...

distractions ?