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Life Sciences => Physiology & Medicine => Topic started by: thedoc on 08/10/2015 22:50:01

Title: Why do I wake up before I need to?
Post by: thedoc on 08/10/2015 22:50:01
Renny McCullough asked the Naked Scientists:
   My Big Question...

I wake up most mornings around 6am, but don't have to get ready for work until 8am. During the two hours I lie in bed, trying to sleep, but it isn't until around 7.50am (or later) that I start to fall into a deep sleep, In case the working pattern is relevant I work 9-5.30, so mostly I have evenings to myself.

I have the same experience on a Sunday when I'm due to see my parents and get up much later, around 11am.

Several friends have confirmed they have had the same experience, these people range in age and I have encountered the same in different work places.

Obviously seasons are changing at the moment, but we seem to have the same experience, despite my 'see through curtains'. Is there an actual biological reason? It can't just be me and my friends that has this experience.

Thanks for a great show that covers so many fantastic topics. Who else would I have to ask such a question.

Best regards,
Renny McCullough
Avid Fan & Science Dual Award (GCSE)
What do you think?
Title: Re: Why do I wake up before I need to?
Post by: Thotmose the 3rd on 09/10/2015 20:06:28
Either you are being smitten by a wicked conscience every night or you are practicing inadequate sleep hygiene.

I betcha your GCSE scores leave you quite capable of looking up proper sleep hygiene to see what you are doing wrong.

Either that or you need to see the padre.

As an alternative, you could visit the web page of the Confraternity of Saint James and take the pilgrim road. It is halfway through the autumn season, so you should choose your underwear carefully, or wait until Spring. I guarantee that by the time you have crossed Asturias with 20-30 kilos on your back, you will be able to sleep soundly even in a co-ed alburgue dorm half full of Swedish, French, and German girls

Pleasant dreams.
Title: Re: Why do I wake up before I need to?
Post by: chris on 12/10/2015 08:02:28
Hi Renny

The average person requires about 7-8 hours of sleep per night. But when we actually "feel" tired and when we wake up is controlled by the body clock; this is a genetic domino effect operating in every cell in the body and governed by a master clock in the brain called the suprachiasmatic nucleus (SCN).

The SCN comprises a network containing about 20,000 nerve cells. These keep time by activating a cycle of genes that turn each other on and off in a sequence and at the same time alter the activity of the nerve cells. Signals from the clock are transmitted to other parts of the brain to influence behaviour. The clock also controls the release of wake-up signals like the blood hormone cortisol, which goes around the bloodstream setting the clocks of the cells in every tissue.

The SCN clock is itself set by signals coming from the eyes. This is how you adapt to changes in the day length or adjust to new time zones. However, this take a while to happen (about 1 day per time zone) because the clock signal is quite resilient (to stop it wandering by accident). And because it "learns" the rhythm of your life, and doesn't know about weekends, it still gets you up early every day, regardless of whether it's a Saturday or not!

Some people do wake early quite naturally; this is because the body produces a surge or cortisol in the early hours to stimulate metabolism and prepare for the day's activities. In some people, this can cause them to be an early riser. Another group of people who wake up early and struggle to fall asleep again are individuals with depression and anxiety. I hope that this doesn't apply to you. It's probably owing to a heightened cortisol release, which occurs in stressed individuals.

I hope that's helpful.

Chris
Title: Re: Why do I wake up before I need to?
Post by: Colin2B on 12/10/2015 13:18:03
During the two hours I lie in bed, trying to sleep,...
Renny
In this situation, I get up and start the day, it might mean I am tired later, but it usually means I sleep better the next night.
You don't say what your length of sleep is.
Are you exposing yourself to daylight equivalent (blue light eg computer screen) late eveining?
Do you get a good daylight 'fix' early morning?


The average person requires about 7-8 hours of sleep
Chris
I have read that we sleep in blocks or cycles of 90min, although some research suggests 90-120. This might suggest that Renny's early morning attempt to get back to sleep is putting him into the deep part of the cycle.
There are suggestions that we should set our alarms in multiples of 90 in order to avoid interupting a deep sleep period.
Do you have any views on this?

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