Atypical sleep type

According to the latest sleep research, one’s sleep type is regulated by specific genes.

15-25 percent of the population is made of B-persons. 10-15 percent are A-persons. The rest of the population are more or less either one or the other, or something in between.


Early birds (A-persons) have been found to have a 23 hour diurnal rhythm (also called ‘Advanced Sleep Phase Syndrome’). Usually fall asleep early at night and wake up bright and early in the morning.

Night owls (B-persons) often have a 25-27 hour rhythm (also called ‘Delayed Sleep Phase Syndrome’). Tend to be more nocturnal and function best at night.

“I tend to push the day forward with one hour per day. The 25-hour rhythm is most noticeable when I don’t have work/school.”

Emma, Aspie from Sweden

“My body clock doesn’t run on 24 hours. My body clock runs closer to 25 hours or slightly longer. Because of this, my sleep/waking pattern wraps around the clock if I’m not careful. This isn’t a problem for me. The problem comes because the world runs on a 24 hours clock as do most of the people in it.”

William, Aspie from USA

My sleep cycle seems to fairly consistently follow the moon’s 24,8 hour cycle (I’ve kept a sleep diary, that’s how I noticed the similar pattern), which usually coincides with the sun’s (or rather the earth’s) only during the time of the new moon. In the summertime it is somewhat easier to keep a 24-hour rhythm, in the winter all but impossible.

– Ing, site-author

“I work best at night, then it’s nice and quiet for a change.”

‘Underjord’, male Aspie from Sweden

“I normally go to bed at 6 AM and sleep until 1 or 2 PM. Sometimes I’ve gone to bed later too. And sometimes – on rare occasions – even earlier, though not before 4 AM. That’s what my rhythm looks like. But I think it feels wrong to sleep away the night, because that’s when it is finally quiet. No people walking in the stairs, no cars passing in the street etc. It is at night I can concentrate on things, for example my studies. So it feels really wrong to sleep at night because that’s when I come alive and am most alert.”

Maria, Aspie from Sweden

Some have even more unusual sleep patterns.

“I haven’t had so-called normal sleep in all my adult life, I think… I sleep so that every second week or so I’m awake in the daytime, and every other week I’m awake all night…”

‘FreeSpirit’, male Aspie from Sweden

“I have a weird sleep rhythm, I’ve noticed, it seems natural for me to be awake 48 hours and sleep 14 – 16 hours… doesn’t at all take a toll on me oddly enough, but I’m not allowed to keep this rhythm because of all the things one has to do every day. ‘musts’.”

– ‘skruw’, Aspie from Sweden

“The day should preferably be 28-30 hours. Often takes many long hours to go to sleep, but once asleep I usually sleep 10-12 hours. (If I can.) When I’ve had enough sleep I’m usually awake for 16-18 hours before I get tired.”

‘Leon’, male Aspie from Sweden

Among those with non-24-hour sleep rhythms, there are many whose internal clock is easily reset by light so that it stays synced with the sun and follows the 24-hour cycle if they only get enough daylight (in the morning for B-persons, in the afternoon for A-persons).

Others have an internal clock that stubbornly follows its own cycle, no matter what.

Having a non-24-hour sleep rhythm is often an inconvenience when living in a 24-hour society, but that may be changing. Some schools and work places have specialised in catering to those with atypical sleep rhythms and more will probably come. Especially for studying, factory- & office work, there is no reason whatsoever for it to have to be done early in the morning. In those cases where B-person students and employees have been allowed to choose hours that fit their type better, the results have been very positive (surprise, surprise).


B-Society Advocacy site for ‘B-persons’ (Night Owls)

DSPS very extensive and informative blog about atypical sleep patterns

Were you born to snooze? article by Dan Roberts

An Examination of the Relationships Between School Start Times and Adolescent Behavior and Learning article



  1. Did not know this about sleep types! Cheers, gr a Night Owl

  2. jose said,

    i go to sleep at 9pm and wake up at 6am.

  3. bluenan said,

    I am 40, been a night owl since 12 (my first non-sleep night was at 13 because I passed all the night reading…). I tend to be much more creative at night.

    I am tired of trying sleeping “normal” – and i need a steady routine, so I am doing a weekly rotation (27h. 27h. 27h. 27,5h. 27,5h. 28h., no alarm clocks… ).

    Not fully tested yet, but the timing is very good for me because I work at home in the studio and as a dj during the weekend.

    And I am glad to read that this patterns are getting better known.

  4. Lucius Zipperer said,

    This is interesting, I’ve always been told I’m undisciplined and lazy, but the truth is, my body runs on a night cycle. I have absolutely no problem waking up when the sun goes down and going to sleep when the sun comes up, and being fully functional. Now when I try the exact opposite, waking in the morning and going to sleep at night, it’s impossible because all day I’m extremely tired and feel like I could sleep at any moment, then the sun goes down and I’m fired up and wide awake. This problem has caused me all kinds of issues in life, and it’s good to know this might not be as rare as I thought.

  5. I usually sleep 2-4 hrs a night and then take 1-2 naps in the afternoon.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: