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.
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.
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!
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.