Thursday, August 15, 2013

Using your Fitbit One data: Sleep

In this blog, we will go over the many ways to use the Fitbit One sleep data.  In a previous blog post found here, I went over the benefits of the Fitbit One Activity Tracker.  Compared to the older Fitbit Ultra, I find the Fitbit One to be a big upgrade.  However, there is also a lower end version of the Fitbit called the Fitbit Zip.

The primary differences between the two are that the One measures flights climbed as well as sleep.  While the flights climbed is a pretty good data point considering the work is more vertical than walking on flat ground, the biggest benefit of the Fitbit One is the sleep data.  This data is useful to help identify issues you may be having with:

  • Identifying lifestyle factors that can impact sleep
  • Identifying food sensitivities you may have 
  • Not getting enough physical activity
  • Getting too much physical activity
  • How your sleep changes over time
  • How your sleep changes over the week
Below is a picture of the data the Fitbit One collects on sleep.  This is from the Fitbit App for the Iphone 4S, the data on the dashboard found at contains more information.

As you can see, the app gives you data on how long you were asleep, when you went to bed and when you woke up, and when you were restless or awake throughout the night. All of this is good data to have and can illustrate things that you may be doing that aren't particularly good for your health.  However, one of the knocks on the sleep data the Fitbit collects is that it isn't really measuring if you are asleep.  Since it is merely worn on your wrist, all it is measuring is whether or not you are moving.  In other words, you can just lie still and it will measure you as asleep.  This is really isn't a problem if you look at the data.

Anyone can see the difference between these two sleep patterns.  Whether you are attempting to stay as still as possible or not, there is something going on in night 1 that isn't in night 2.  Keep in mind that these are both Thursday's sleep which means they were recorded on Wednesday night in to Thursday morning.  First, we can see that while the first Thursday's sleep was almost 45 minutes longer, it was of much poorer quality.  There was more than likely something going on either on this day or leading up to this day that led to poor sleep.  There are several reasons why this may happen when comparing the same day of the week over time.

1) Hidden food sensitivities

It is possible that something or some things were eaten on the first Thursday that weren't on the second Thursday that negatively impacted sleep.  A common symptom of a food sensitivity is poor sleep, and not all food sensitivities will have overt GI symptoms.  Since the best way to identify a food sensitivity is to make a food journal, you can compare the two.  Luckily, the Fitbit allows you to log all of your food so you can easily enter it in the App or Dashboard and access it from either.  Over time you can narrow down foods you are sensitive to by eliminating foods one at a time and watching how they affect your sleep cycle.


Too much stress can also negatively impact sleep.  Maybe you were approaching a deadline at the end of the week of the first night but not the second.  Obviously you can look at this and see the effect stress has on sleep quality, even if you get to sleep in.  You can also record subjective info like this on your Fitbit Dashboard or in the App.  The benefit in this situation is that you can see that you should take active steps to manage stress or your sleep will suffer.

3)Too little physical activity or too much

You can compare the sleep data from both days to the step data on both days and see if you may have slacked on getting your steps in.  Too little physical activity during the day can lead to a surplus of energy at night and difficulty sleeping.  On the flip side, you could be entering a state of overtraining by overexercising.  This will cause your body to shift in to fight or flight mode which will make it more difficult for you to get in to rest and digest mode.  In this instance you will want to cut back on your exercise for a while until your sleep improves.

4)Whether an intervention is working over time

Most people associate the word intervention with a drug or alcohol problem.  What I am referring to here is a health intervention you apply to a health condition.  If you are having problems and try to remedy the situation, looking at how the intervention affects your sleep can be a huge benefit.  In this instance you wouldn't use just two data points, but if all of the other data points trend in the right direction you know you are on the right path.

You can also look at the data over the course of a week to find trends.


As you can see, it appears that this person sleeps better later on in the week.  I've looked at all of the other data throughout the year and this is a pretty standard trend for this person.  In this instance we can identify things that the person may be doing on a weekly basis that negatively impacts sleep.

1)Coffee consumption

Maybe this person drinks more coffee on the weekends.  You would expect coffee consumption to be greater during the work week, but this person could work weekends and have Tuesdays and Wednesdays off.  If they avoid coffee on these days but not the other days that could certainly be an issue as coffee is a stimulant that could potentially impact sleep on days it is consumed.

2)Alcohol consumption

This is actually what is happening in this picture.  This person drinks alcohol on the weekends but abstains during the week.  As a result, not only is their sleep disrupted on Friday and Saturday nights, it carries through in to Sunday night's sleep.  In this instance, the person actually consumed a small amount of alcohol at a celebration on Sunday during the day.  However, this disturbance in the sleep cycle is similar whether they confine alcohol consumption to Friday and Saturday or they allow a little consumption on Sunday as well.

3)Any significant changes that impact sleep

It could also be some other change you make during the weekend that negatively impacts sleep.  Going back to a lack of physical activity, most people don't exercise on the weekends or reduce general physical activity such as walking.  Binging on junk food during the weekends could also negatively impact your sleep.  Tweaking these things and then looking at your sleep data can give you tremendous insight in to what may be causing your sleep to change over the course of a week.


As you can see, the sleep data that the Fitbit One collects is pretty cool and useful.  Whether you are just looking to live a healthy lifestyle or you are working on improving a health condition, using the Fitbit One can give you a little more information that can help you make the right decisions.  You simply wear the Fitbit One in the wrist strap that is provided with it and hold the button until the counter starts when you are ready to go to bed.  When you wake up in the morning, you simply hold the button again until the counter stops.  If you forget to start and/or stop it but wear it anyway, you can enter the time you went to bed and/or the time you woke up in the App or the Dashboard the next day.  The data was collected as long as you wore it.  The best part...the silent alarm doesn't jolt you out of bed.