I’m one of those people who needs more sleep than I get, so I’m always interested in finding ways to improve the quality of my sleep. Earlier this year, I purchased a Zeo, which is a small device that measures and records your phases of sleep. You can upload this data to a website which also allows you to manually log a number of other factors associated with sleep in the form of a sleep journal.

I just completed 100 days of recorded data on the Zeo, and I thought it was time to look for some overall patterns. While the website provides a number of simple ways to do this, I decided to download the raw data and analyze it myself.

Overall Numbers

To calculate top-level results for the 100 nights of data, I took out any nights that were statistical outliers (i.e., the headband fell off, etc.); there were only 4 that were obvious outliers.

Here’s what an “average” night looks like, broken down by sleep phases. The majority of the sleep I get is in the light phase, then REM, and deep, with only a small amount of wake time. (Evidently, most people are awake for short periods like this, even if they don’t remember it.)

I also calculated typical ranges for each phase of sleep. The median is the most likely value I would experience for phase. The range is the bottom 10 percentile of the data to the top 90 percentile. In other words, 80% of the data fall into this range, so it is a good representation of the spread of “typical” results look like for me.

For those interested in such details, the distribution analysis above was performed using JMP v.8, and I’ve provided a screenshot of the output if you’d like to take a look.

There is nothing in these results that are particularly revealing. It’s when I compared the sleep phase data to the sleep journal information that things got interesting! I’ll post those results tomorrow.