Sleep Graph V. Pie Chart: What’s the Difference?

by Chelas@Zeo on October 27, 2010

in About Zeo,Sleep Data

Working in Customer Service, I’m often asked to explain the Sleep Graph and the Pie Chart that shows up in a user’s myZeo account. A common question goes something like this:

What’s the difference between the Sleep Graph and the Pie Chart? If it’s the same data in each, why have two graphs?

Sleep History 101

The reason behind this is that we wanted to give you a more detailed picture of your sleep.  By having two different views of your sleep data, it’s easier to identify any potential sleep stealers.

A Typical Night's Sleep For Me

Between the two, the main difference lies in how each one divides up a night of data. The Sleep Graph is a history of your sleep phases across a night while the Pie Chart shows the percentage of time you spent in each phase.  In order to do this, both the Sleep Graph and Pie Chart need to process the raw sleep data in different ways.

As we mentioned in an earlier post, Zeo records your brain activity and decides every 30 seconds whether your awake or asleep (and if asleep, what stage you’re in). These 30 second intervals are then used to calculate the Pie Chart.

At the same time, Zeo bunches these 30 second periods into 5 minute blocks in order to name the stage of sleep you’re in for the majority of that time. This is the data that produces the sleep graph.

  • Exception: The Sleep Graph will always show “wake” even if it was not the majority of that 5 minute block. You can see an instance of this on my Sleep Graph just after 5am.

My Sleep as Recorded in 5 Minute Increments

The Devil is In the Details

That said, a person can shift between sleep phases within a 5-minute period.  What this means is one could be in Deep Sleep (or any other sleep phase) many times during the night, but not see it on the Sleep Graph because you where only there for a minute or two.

This is where the Pie Chart comes in.   Since it looks at the overall percentage you spent in each phase, you still get an accurate measurement of how much Deep Sleep you got.

Remember that 5 minute block of Wake in my Sleep Graph?  Turns out I was only awake for a minute–thanks, Pie Chart!

My Total Sleep as Recorded in 30 Second Intervals

In short, the Sleep Graph shows you when you’re (roughly) in each phase during the night, while the pie chart shows how much time you’ve actually spent in each.  By having two complimentary ways to explore your data, in the end you can get a much richer picture of your own sleep, night to night.

But wait….What if I want to see my sleep history in shorter increments?

While we don’t have 30 second sleep graph (yet), you can still look at your sleep history from start to finish on a micro level via our Data Export Feature.

If all this has sparked any questions, let us know!  You can comment below or send us an email.  Better yet, ask an Expert!

Related Post

Chelas (ZQ: 85) is our all-star Customer Support Representative.  If you’ve reached out via Live Chat, called our 1-888 number, posted a question on our Forum, or sent us an email, chances are she helped you out. :)
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{ 3 trackbacks }

Behind the Headband Part 2: The Sleeping Brain and Body
May 10, 2011 at 11:47 am
What’s the Deal with Wake?
August 17, 2011 at 3:33 pm
Sleep Graph V. Pie Chart: What’s the Difference? | Sleep Tight
September 28, 2011 at 2:27 am

{ 2 comments… read them below or add one }

1 Todd Brown October 27, 2010 at 9:58 pm

Helpful article, thanks! This brings up a question I’ve had regarding the impact of how many times one stays and/or changes from one phase to another in a given night and what the averages are for this? For example, your sample graph appears to have 20 or so ‘changes’ during a given night whereas mine, on average, seem to have almost twice that many. If I’m still getting a good overall score and total REM & Deep Sleep, does it matter how short or long the individual increments are?

Thanks!

Reply

2 Chelas November 2, 2010 at 12:49 pm

Hi Todd,

Thanks for your question! Many shifts in sleep phases during the night, but waking up feeling rested is probably okay. There’s lots of variation in how many sleep phases shifts someone experiences, from night to night and from person to person. However, lots of sleep phase shifts during the night can often leave us feeling like we never got a full, restful sleep. If you are waking up feeling tired and not well rested, even after a long night of sleep with plenty of REM and Deep sleep, you might want to speak with your physician about other potential sources of fatigue.

Sleep Well,
Chelas
Zeo Customer Care

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