Purpose:

All human bodies get naturally sleepy in the middle of the day. A quick nap resets that biological clock for 8 hours.

Practice:

I take a 20-30 minute nap on lunch break.

When I nap, I sit up or lay in a place where it will be difficult to fall deeply asleep, and use sound-blocking headphones. The nap typically happens in distinct phases:

- Nothing seems to be happening at all

- I feel slightly relaxed, thoughts proceed at normal pace

- Body feels heavy and pleasant, thoughts quiet down a bit

- This is where my awareness normally starts fading

- Thoughts begin to mix up illogically

- Pre-dream imagery begins

- Awareness is almost completely faded at this point, or does fade into the next phase of sleep

- Now the alarm wakes me up before I go too deep

I almost always want to sleep more, but when I resist that feeling for 2-3 minutes I usually will feel totally refreshed.

That last point isn't usually true when I'm are in a state of chronic sleep deprivation. For that, a 90 minute nap is more effective (if timed correctly and not allowed to become a 3, 4, 5+ hour nap).