I wound my way backwards into some interesting sleep data this weekend.  Since I freelance from home, I don't have a job asking me to get up at a particular time.  This can cause problems with my schedule, because I tend to sleep in a little bit later each day.  At one point last week I slept in until 11AM!  People, that is ridiculous.

In trying to reset my schedule I wondered, what time do most people get up?  This seems like it should be an easy question to answer.  But it turns out that not very many surveys have been done on wake up times.  I finally found one buried in a study about something else, from the National Sleep Foundation.

The NSF's 2005 study is titled "Adult Sleep Habits and Styles," and their "sleep segment profiles" sub-study [PDF] lists average wake up times by sleep segment.  And, more interestingly, it divides everyone into groups of sleep patterns.  Some healthy; some not!

The two healthy groups are the "Healthy Lively Larks" and the "Sleep Savvy Seniors."  Are you surprised that retired seniors get enough sleep a night?  I didn't think so!  But I was surprised to learn that most seniors wake up "after 7:00 A.M." despite the perception that seniors always get up at the crack of dawn.  (In fact, this perception was the key to an episode of South Park - no one could defeat the senior citizens, because they wake up so early.)

The other healthy group is "Healthy Lively Larks," those early risers everyone else loves to hate.  Surprisingly, larks comprised 27% of the surveyed population, even though I always thought early risers were a lot more rare.  Most Larks are out of bed by 7AM, are healthy, employed, rarely feel tired over the course of the day, and usually get 8 or more hours of sleep per night.

There is a lot of evidence that getting enough sleep - between 7 and 9 hours per night - is important for your health.  The New York Times recently reported that there is a link between not getting enough sleep and being overweight.  

This link was also picked up by the NSF, who dubbed their least healthy sleep segment "Overworked, Overweight, and Over-Caffeinated."  This segment is obese, unhealthy, gets less than 6 hours of sleep a night, is more likely to smoke, drinks way too much coffee, and is predominately male.

Towards my original question, what time do most people wake up, most of the OOO group is up by 7AM as well.  It's just that most of them are going to bed between 11PM and midnight, whereas most Larks go to bed at about 10PM.

In fact, if you look at the study's numbers, you can see that pretty much everyone is up by 8AM.  They break down their numbers by hour (5AM-5:59AM, and so forth), but everything after 8AM just goes into a giant four-hour bucket of "8AM to noon."

Luckily for my original question, the NSF has provided a "Total" column.  Most people (29%) wake up between 6 and 7AM.  The next runner-up is between 5 and 6AM, with 24%.  So if you want to be normal, set your clock between 5 and 7AM - and if you want to be healthiest, go to bed between 9 and 11PM!

Creative Commons-licensed image courtesy of Flickr user Jordon