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I have been observing my sleeping patterns from several days. Here are my observations:

  • If I sleep at around 12:00 AM, I wake up at around 09:00 AM. (9:00 hour sleep)
  • If I sleep at around 02:30 AM, I wake up at around 09:30 AM. (7:00 hour sleep)
  • If I sleep at around 04:00 AM, I wake up at around 10:30 AM. (6:30 hour sleep)
  • If I sleep at around 05:00 AM, I wake up at around 11:00 AM. (6:00 hour sleep)

These observations are made when I don't use any alarm and wake on my own. So, Now, I am wondering why I daily wake up around 10 AM no matter how many hours I sleep. What is the reason for this? Also, Some time I plan to sleep early (around 11 PM) and wake up at around (4-5 AM) but most of the time I fail even after using an alarm. Why it is so?

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What is your sleeping environment like? Factors like light, noise and temperature can effect sleep patterns. – Kramii Dec 19 '13 at 14:42
@Kramii I live in hostel. There is neither not much light in the room in the morning nor some kind of noise – Anonymous Dec 19 '13 at 15:14
Are you sure you don't mean "12:00 AM" The PM/AM switch happens at 12, not 1. 12 PM is lunch time. – jmort253 Dec 19 '13 at 16:42
@jmort253 Sorry my mistake. Corrected it – Anonymous Dec 19 '13 at 16:53

Most likely you have yet normally functioning circadian rhythm.

There is circadian rhythm in your body/brain regulated by hormones like serotonin and melatonin. Also there is some special cells on human retina, regulating this rhythm. Even small amount of day light enough to change phase of the rhythm.

You can find more information about this topic in the Wikipedia:

I'm highly recommend you not to brake circadian cycle. You going to ruin your life. I have strong sleep disorder myself, and this is real pain.

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This doesn't really answer the question. Answers should ideally be more than just a one-line answer. Can you elaborate? See How to Answer for more details. – jmort253 Dec 19 '13 at 16:43
@jmort253 - I have no time to make more detailed answer. I just want to warn Anonymous to save his/her ability to sleep normally. – alex Dec 19 '13 at 17:38
For one liner answers always try to use comments – Anonymous Dec 19 '13 at 18:10
This is better Alex. Nice edit! :) – jmort253 Dec 19 '13 at 19:12
@Anonymous, I did comprehensive sleep study here: . All they said after study was "yes, you have sleep apnea". Everything else was just common words, you can find in Wikipedia and other popular reading. The complete answer to your question would be done by direct measurements of the melatonin and serotonin in your blood during sleep/awake periods. Everything else would be just a guess. – alex Dec 19 '13 at 20:13

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