Do you have an Internal clock? Would you trust it?

Ok so this past weekend I had a very big project I was leading. It involved around 20 people and I was in charge. I had to be at our rendezvous point at 5:15 am Saturday because I had the keys. Missing it would have been disastrous. I use my cell phone as an alarm and so I set it like I usually do just a little earlier for 4:45am. I went bed at around 10 the night before confident the alarm would wake me up. Well the alarm did not go off at 4:45, because I had it set elsewhere to only go off on Monday – Friday. However, my body woke me up at 4:47 and I was perfectly awake. Holy crap how awesome.

So do you have an internal clock that you can trust? Can you sleep well knowing that your body will wake you up if there is a consequence for being late?

I haven’t worn a watch in years but I have a pretty good idea +/- 5 minutes of what time it is at any given point of the day.