The proper way of tracking your sleep – Thoughts about Emfit QS

When you think of tracking your sleep I bet you’re thinking about an app like Sleep as Android or Sleep Cycle. You might even have a Fitbit, a Polar Loop, or a Jawbone Up to track your nightly activity. Those should do the trick, right? Well, yes and no.

The problem with all of the sleep tracking methods mentioned above is that they’re mainly based on detecting movement and can’t really tell much about the quality of your sleep. Sometimes you’ll lay on your bed wide awake and your sleep tracker will think you’re asleep. A colleague actually mentioned his tracker once thought he was asleep even though he was just watching a movie. I’ve been using a Fitbit Charge HR for a while, and it seems that even the 24/7 HR detection doesn’t do Fitbit much good in terms of sleep quality tracking accuracy. Basically the only figure I can trust with the Fitbit is the duration of my sleep.

As a biohacker, I figured I would need a sleep tracker I can actually trust. How else am I going to measure my sleep quality hacks? Fortunately there’s now an answer, the Emfit QS. Emfit is a Finnish company founded in 1990, so they’re not exactly a start-up anymore. They were showcasing the QS in the Biohacker Summit 2015 and I just couldn’t resist ordering one.

I have had the QS for two three days now, and the first impressions are very positive. So let’s have a look.

Unboxing & Setup

The device itself comes in a sturdy printed box, which has a premium feel to it. A bit like iPhone packaging. Emfit did a good job there. The box contains a quick start guide, the device itself, and a power supply.  The quick start guide didn’t include a description on how to place the QS in your bed, so I actually thought my package was missing a manual. The only clue on how to install the strip itself was on the back of the printed box. It turned out to be very simple to install anyway. There are two adhesive patches that keep the QS in place under your mattress.

The quick start guide describes how to connect the QS to your WiFi. It recommends a WPS based setup, but I couldn’t get that working. To be fair, I’ve never used WPS with my WiFi access point, so I don’t know if it even works. The other option was to connect to the ad-hoc WiFi access point that the Emfit creates, and configure the QS via a browser. The latter option was straight-forward and simple.


To measure your sleep quality, just go to sleep and wake up. Done. Using the QS couldn’t be easier.

I haven’t tried how it works if I read in bed for instance. The first night my wife laid too close to the QS on my side of the bed before I went to sleep, and that threw off the sleep metrics a bit. I moved the strip closer to the edge of my side of the mattress, and that seemed to help. Emfit founder Heikki mentioned that deleting such unintentional measurements would become possible very soon.

The Data


Emfit doesn’t have a mobile app for viewing your data. Instead, they have a web service at The site also works nicely with mobile browsers. The only downside was that the pages would load a bit sluggishly at times. Perhaps that was just my network being slow.

Most of the data is easy to understand even for a non-biohacker. There’s for example time, heart rate, breathing rate, and toss & turn. There’s also a sleep score, which is probably the simplest way to measuring most changes you make in your sleep routine. The beta version of the site also features a sleep efficiency figure.

Another nice feature – which is supposed to actually be accurate on the QS – is the stage of sleep you’re in. The sleep stages are awake, REM, light, and deep sleep. I’m using a Fitbit HR as my second device to measure sleep, so in a few weeks I should have enough data to make comparisons and perhaps say something about the accuracy of Emfit QS.

What sets Emfit QS apart from the Beddit sensor for example is the fact that the QS can measure heart rate variability (HRV RMSSD), and “nervous system balance”. Heart rate variability tells about your stress and recovery levels. A very low HRV means you’re stressed out, and your body is in fight-or-flight mode (as opposed to rest-and-recover). A very high HRV on the other hand might be a sign of overtraining or just extreme relaxation. Breathing exercises and meditation can actually be used to reduce your stress levels and increase HRV. Overall, you want your HRV to be balanced. The meaning of the nervous system balance figure on the other hand is not clear to me as of today. I need to do some studying on that.

In addition to the “Sleep Period” page in the picture above, the web service has a “Timeline” view which is just that. A timeline which shows when you were sleeping, and when you were not in bed. I didn’t find this very useful based on two three nights worth of data. The third view is called “Monitor” and it will tell you whether you’re currently in bed or not. It’s an (almost) real-time view to your bed. There seems to be a slight delay in this. The fourth view is “Trends”, which is shown below with just my three days worth of data.



Emfit lets you download your sleep data for each day as a zip that contains a bunch of CSV files. I’d be interested in creating an automated Google Script that would fetch my data to Google Drive. I’m planning on publishing the scripts in this blog as soon as Emfit publishes their API documentation.


I contacted Emfit via Facebook to ask about the installation, and got a quick answer from the company founder Heikki Räisänen. He also pointed me to the beta version of the web site at I also asked about the availability of a public API, and was told that the API already exists, but hasn’t been documented yet. Emfit is planning on making it available in the near future. Some new metrics will also be introduced in the beta version soon, which is cool. I love it when a product I already paid for gets better via software updates!


So far I’m very happy with my Emfit QS. It’s supposed to be the most accurate sleep tracking device out there that doesn’t involve sticking electrodes on your forehead. I will post an update in the next week or two for more thoughts.

Anyway, based on three days of usage, the QS is a good tool for anyone interested in tracking their sleep quality. You can order Emfit QS directly from the manufacturer.

Do you have the Emfit QS? How is it working for you? Comment and discuss below!

Updated on October 4th: Response to public API query. Added a picture of the Trends view.

2 thoughts on “The proper way of tracking your sleep – Thoughts about Emfit QS

    1. They did not publish the API but there is one and you can use it if you do a little bit of reverse engineering. It’s pretty straightforward if you record your browser traffic in developer mode.


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