Posted by Martin Kyte on 14/02/2017 09:05:58:
Hi Bill
It's also interesting to note that the waking human brain has no perception of how long it had been asleep.
regards Martin
When I set my alarm for the night, I will always wake up about 5-10 minutes before it's due to go off and I don't always set it to the same time. Yet if I set no alarm, I will sleep for as long as I like.
As we know, you can't wake yourself up or know what the time is to get up to when you're asleep, and I've always wondered what's going on in that case. This seems to imply that the body does infact co-inside with time in a physical relationship. My father does the same thing, he can't get out of the habit of waking up at 5:30 for work, when he has no need to anymore.
So the body probably has some sort of internal "clock". Brain chemicals run through cycles during the day, most notably to let you know when you're sleepy. People who do nightshifts tend to suffer from different sets of health problems than those who don't on a regular basis. There's a lot of biological evidence to suggest that our bodies do at least follow a kind of daily pattern with regards to certain brain functions.
This doesn't answer my question of how I can seemingly wake up to a particular hour with unerring accuracy, but it might go some way to explain it. People tend imagine of the "subconscious mind" in a kind of impulsive or irrational sense, but it might demonstrate how sophisticated it can be at other things.
Beyond this, the only evidence we have of time is not clocks, but surely the movements of the planets, stars and our own sun.
Michael W