Sleep as Android now fully integrates with the new fitness-tracking devices from Polar – H10, OH1 and Sense. In addition to heart rate measurement, the app uses the integrated accelerometer to monitor sleep phases and trigger smart alarms. The Polar devices present an affordable, comfortable, and easy-to-use alternative to sleep-tracking with a traditional smartwatch. Read on to see how it works.

Polar has a long tradition in manufacturing wearable devices for fitness tracking and heart rate monitoring. They are marketed mainly as an aid for sports enthusiasts. However, with Sleep as Android, they can be easily turned into powerful sleep-tracking tools.

Sleep as Android integrated heartrate inputs from Polar devices a long time ago. However, their recent models (the chest belt H10, and the armbands OH1(+) or Verity Sense) have also an accelerometer (a motion sensor) included in them. We can read the information about the sleeper’s movement throughout the night and use it for evaluation of sleep phases, triggering smart alarms, and all the other cool stuff that Sleep as Android does.

These devices are relatively light and comfortable to wear, inexpensive, and easy-to-use. We believe that many users will find them more convenient than heavy-weight smartwatch. Furthermore, they provide detailed measurements directly via a well-documented Bluetooth interface. There is no need for a third-party bridge app. And they produce very detailed measurement data, which allows us to supply much more useful insights to the user, compared to most devices from other vendors on the market.

How to make it work

1. Get your H10/OH1/Sense device, attach it to your body and turn it on, according to the user manual.
2. Install Polar Beat, a standard app for controlling the devices.
3. In the Beat app, go to Setting, click on “HR sensor”, and pair the app with your device. Then turn the “Visibility” switch on, so that other apps can communicate with the device. Now you can leave the Beat app, you will not need it anymore for sleep tracking.
4. Start Sleep as Android and go to Settings/Wearables/Use Wearables. Tap on the “Polar (H10, OH1, Sense)” entry. It will pop-up a list of available Bluetooth devices, so select your Polar device from the list.
5. Next time you start sleep tracking, the app will attempt to connect to the selected Polar device. If it is available, its activity and heartrate sensors will be used for sleep tracking.

Troubleshooting

• Only one app at a time can connect to Polar OH1 and two apps to Polar H10 or Sense. If other apps (such as your fitness tracker) are actively using the same device, Sleep As Android may be unable to connect. You may need to terminate these apps before you start sleep tracking.
• Bluetooth tends to be generally unstable and buggy on some Android phones, especially the older ones. In case of connectivity problems, it often helps to turn off and on Bluetooth in the Android setting, turn off and on the device, or restart your phone, as a last-resort step.
• It is a new experimental feature, please let us know in case of any troubles with it.

Available features

Detailed measurements provided by the new Polar devices allowed us to implement some more fancy features. They are available in the latest release from January (version 20210118).

Breath monitoring

As the H10 model is attached to one’s chest, the accelerometer is able to capture even the tiny movements related to breathing. Our preliminary experiments show that it is possible to measure breath frequency and detect respiratory disturbances from it, at least during the parts of the night when the sleeper lies relatively still.

HRV analysis

Time intervals between individual heartbeats tend to fluctuate naturally on a short time scale. This phenomenon is called heart rate variability (HRV). Analysis of an individual’s heart rate variability characteristics may reveal useful information about his health, stress level, or the quality of his rest. As the Polar devices supply detailed beat-to-beat time measurements, our app is be able to compute HRV and offer such insights.