girl sleeping nest

Dance to the (Circadian) Rhythm

A few months ago, Jawbone explored how people move and sleep in the cities of the world. We saw the ways that our lives are shaped by culture, work habits, and holidays, among other factors. One question came up repeatedly: what about the rest of us, the ones who don’t live in cities? Here, we’ll dive into a more geographically complete picture of sleep in the US.

Average Bedtime by US County (Interactive)

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The visualizations, prepared by Principal Data Scientist Brian Wilt, paint a nuanced picture of how people sleep across the country. Overall, the county that stays up the latest is Brooklyn (12:07am), and Maui and Kauai counties in Hawaii go to bed the earliest (10:31pm and 10:33pm, respectively). Gotta wake up early to catch the wave!

When we dive a bit deeper into the counties that stay up the latest, patterns emerge:

The counties that stay up are parts of New York City, and we can rank each borough by insomnia level:

  1. Brooklyn (Kings County): 12:07am
  2. Manhattan (New York County): 11:55pm
  3. Queens (Queens County): 11:52pm
  4. Bronx (Bronx County): 11:47pm
  5. Staten Island (Richmond County): 11:46pm

followed by other party cities with great nightlife:

  1. Miami, FL (Miami-Dade County): 11:54pm
  2. Atlantic City, NJ (Atlantic County): 11:53pm
  3. Las Vegas, NV (Clark County): 11:49pm
  4. New Orleans, LA (Orleans County): 11:47pm

There are college towns in the middle of nowhere, which are basically homogenized with enthusiastic young students staying up late to “study”:

  1. Indiana University (Monroe County, IN): 11:53pm
  2. Cornell + Ithaca Universities (Tompkins County, NY): 11:48pm
  3. Purdue (Tippecanoe County, IN): 11:46pm
  4. Penn State (Centre County, PA): 11:43pm
  5. University of Georgia (Clarke County, GA): 11:41pm
  6. Texas A&M (Brazos County, TX): 11:41pm
  7. Ohio University (Athens County, OH): 11:41pm

And finally, the southern-most part of the continental US, the Texas-Mexico border counties, which all average bedtimes after 11:45pm.

Circadian Rhythms in Time Zones (Interactive)

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In this map, it’s also clear how our sleep can be shaped by daylight. On the westerns extremes of time zones, people tend to go to bed later, and on the eastern edges they go to bed earlier (for example, look at the Central Time Zone). The starkest difference can be seen on the Kentucky/Tennessee borders between Eastern Time and Central Time, splitting the states in half (pictured above). The average difference in bedtime across the time zone border is 16 min (excluding Hamilton County, TN, since it contains Chattanooga), and some places it’s as high as 30 minutes. But why?

  1. Imagine two people in Kentucky, very close to each other but on opposites sides of the time zone border. If they both go to bed 4 hours after the sun goes down, their clocks will say that the person in Eastern Time went to bed one hour later than the person in Central Time.
  2. Now let’s look at the Central Time Zone. It’s 6pm, and the sun has gone down in the middle of Kentucky. It’s also 6pm in western Kansas, almost 1000 miles away, but the sun will not go down for another hour. So people go to bed later in the western edge of the timezone than the eastern edge.

Unbeknownst to us, our body’s circadian rhythms tune to sunlight hours, silently influencing you to go to bed when the sun goes down irrespective of the exact time.

Total Hours of Night Sleep by US County (Interactive)

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One of the major findings in our study of city sleep was that people living in cities just don’t get enough. No major city in the United States averages above the NIH-recommended seven hours of sleep per night. But it’s only part of the picture. The vast majority of the suburban and rural counties have much healthier sleep numbers.

Geography has a profound effect on the routines we follow and the habits we form. Our sleep cycles adapt to the pace and lifestyle of the world we live in and the world by which we are surrounded. We look forward to further investigating the effects of geography and how it influences UP wearers in all parts of the world.

Technical Notes. This study was based on over one million UP wearers who track their sleep using UP by Jawbone. Less populous counties were blended with neighboring counties to generate significant results. This technique revealed patterns at finer granularity than the state level, such as time zone boundaries. All data is anonymized and presented in aggregate.

Update: The author is embarrassed to note he’d never heard the song “No Sleep Till Brooklyn” until the day this post was published.

 

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About The Author

Tyler Nolan

Tyler is a rising college senior studying computer science at MIT, where he plays for the men's volleyball team.