Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why did I wake up before my alarm clock went off? (2015)

joearms.github.io

Post reply on HN
Print view View original

41–50 of 86 posts

Re: Why did I wake up before my alarm clock went off? (2015)

#41

Post by gattr »

I also often wake up before the alarm, and the delta is on the order of tens of seconds. I'd say I definitely get to become fully awake and start thinking about the upcoming day before it rings. Apparently, just a matter of quite a precise internal clock.

Another situation when it can trigger is when I brew tea. I like a "reproducible" brew, so I'm used to setting the timer to 3:30 minutes after filling the cup with water. When I then go do something else and become engrossed in it, I'll often suddenly realize "Oh no, what about the tea?" I then look at the timer and see there are 5-10 s left.

Re: Why did I wake up before my alarm clock went off? (2015)

#42

Post by dctoedt »

Our two dogs seem to do this. They sleep in our bedroom. We get up at 0500 to walk them before going to the gym. Usually we're up before the alarm goes off, but not always. If we sleep until the alarm goes off, typically around 0458 the dogs will be up and standing next to our bed; they shake their heads around so that the sound of their ears flapping will get us up.

Re: Why did I wake up before my alarm clock went off? (2015)

#43

Post by projektfu »

md_ wrote: post #6

The famous experiments from Benjamin Libet seem relevant here: https://en.wikipedia.org/wiki/Benjamin_Libet#Implications_of... . In particular, see Daniel Dennett's response (the relevant aspects of which are quoted on the Wikipedia article linked above). I will say, I don't think this is a terribly interesting _example_; as others have noted, it's not uncommon to actually wake up minutes before the alarm goes off. (…

Yes, I believe this is the same phenomenon as the "long second", where you glance at a clock and it takes longer than your perception of 1 second for the clock to move, then it ticks along normally. This is because the brain noticed you changed your view and didn't want a discontinuity in processing so it makes itself think that there is a fraction of a second more of the initial image. (or something like that, probably more complicated.)

Re: Why did I wake up before my alarm clock went off? (2015)

#44

Post by thedanbob »

kempbellt wrote: post #36

An alarm going off if a very disruptive disturbance to your sleep cycle, and it is predictable. Your subconscious mind perceives it as a predictable negative event and wakes you up in an attempt to prevent the disturbance. Goes to show how cool our brains are.

After I got an Apple Watch I started wearing it to bed and using it as my alarm. I can't remember ever waking up just before it goes off although that would happen a lot with my old alarm. Perhaps because a vibration on my wrist, while still effective at waking me up, is not nearly as disruptive and negative as an alarm.

Re: Why did I wake up before my alarm clock went off? (2015)

#45

Post by projektfu »

bwi4 wrote: post #26

Not a biologist, but circadian rhythms are attributed to light. Could the light level in the room be the trigger for waking before the alarm goes off?

Light mediates them, but there are a lot of clock-based behaviors in animals and they usually anticipate events. They can occur in complete darkness. Searching PubMed for "time sleep anticipation" produced interesting results.

Re: Why did I wake up before my alarm clock went off? (2015)

#46

Post by kempbellt »

thedanbob wrote: post #44
kempbellt wrote: post #36

An alarm going off if a very disruptive disturbance to your sleep cycle, and it is predictable. Your subconscious mind perceives it as a predictable negative event and wakes you up in an attempt to prevent the disturbance. Goes to show how cool our brains are.

After I got an Apple Watch I started wearing it to bed and using it as my alarm. I can't remember ever waking up just before it goes off although that would happen a lot with my old alarm. Perhaps because a vibration on my wrist, while still effective at waking me up, is not nearly as disruptive and negative as an alarm.

>is not nearly as disruptive and negative as an alarm

My personal experience says this is likely the cause as well. A vibration on your arm is a lot less disruptive as "EENENENNNG..... ENENENENNG....ENENNENN" right in the middle of a dream.

Re: Why did I wake up before my alarm clock went off? (2015)

#48

Post by jonplackett »

AdmiralAsshat wrote: post #13

Personally, I rarely wake up before my regular alarm goes off. However, if I have to wake up earlier than I normally do for something (dr's appt, scheduled flight, etc), my body seems to wake itself up every couple of hours out of fear that I will sleep through the alarm. So I normally wake up at 8 and sleep soundly through the night, but if I've gotta be up at 7 for some reason, even if I have an alarm set, I seem t…

Exact same experience. Me and my stupid brain are not alone!

Re: Why did I wake up before my alarm clock went off? (2015)

#50

Post by rconti »

madaxe_again wrote: post #32
JoeAltmaier wrote: post #14

Nope. I slept in a common room with 3 brothers. If my alarm went off (half an hour before they needed to get up) I got a whopping. So I would wake up moments before the alarm, scramble from bed to my desk and slap the snooze button sometimes just as the buzzer started to sound. This guy is over-thinking it. And underestimating the human brain.

Yup. I grew up in dorms at boarding school. The art was to wake up five minutes before the bell, so you could be first in line for the showers and get hot water, and then to breakfast before they ran out of the good choice. You couldn’t have an audible alarm, as you’d wake others and then you’d have competition. So, you just trained yourself to wake on time, at 0657 or whatever time shortly before 0700 you thought wi…

The book Why We Sleep discusses the phase of our sleep that has extremely accurate timekeeping. I've forgotten the details, of course. But I think it's quite clear our brains know precisely what time it is.
Post reply on HN