How does the Lark sleep pattern sensor work?

Lark contains a micromotion sleep pattern sensor that records thousands of data points every minute about your movements during sleep. Using actigraphy algorithms developed by sleep researchers, Lark then determines your sleep quality and when you're sleeping, falling asleep, awake and tossing and turning.  Actigraphy is the most accurate way to monitor sleep patterns without actually measuring brainwaves, and is about 85-95% accurate for healthy adults.  Actigraphy is not, however, well suited to monitoring sleep stages such as deep sleep or REM sleep which is scientifically determinable only with brainwaves. Contrary to popular belief, adding additional sensors to the Lark wristband will not improve its accuracy.

For more information on actigraphy, please see this recent article.
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    Hsiang Hsu

    So would it affect the accuracy if I wear the band on my foot?

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    LARK Engineering

    Hi Hsiang,

    Wearing the Lark on your foot/ankle may affect the accuracy of your sleep data. According to our sleep experts (and the research community), you should wear the LARK on your dominant hand (usually the one you punch with) for maximum accuracy.




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    Amanda Sanguinet

    Jack - You should put this information and other getting started information in the box for first-time users.  I am a new user and didn't know to wear it on my dominant hand. 

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    Is the top of the wrist (like a watch) better to wear the Lark on or underneath? Does it matter?

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    Hi there - it doesn't matter which hand you use, or how you wear LARK on the wrist orientation wise. I hope this helps! 

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    Alex Hazel

    I have an app on my iPhone that does a similar thing and it's called Sleep Motion X. Unlike the Sleep Motion X (and I have only tried it once...) it seems that the LarkLife wakes you up exactly at the time you set for the alarm instead of the best possible time in your sleep cycle. This can lead to users waking up at inopportune times in their sleep cycle and left feeling groggy. Would you guys think about adding a "time window" that would allow the app to wake you up during a time that is best in your sleep cycle that falls into the window of time you chose around the time you set for your alarm?

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    Jenny Quan

    Currently, the actigraphy (motion-based) technology that we use cannot provide information on sleep cycles. In order to do something like this accurately, the app or device would need to read brain waves similar to an EEG. 

    We are always looking at ways to improve our users' experiences, so appreciate the feedback on a window of wakeup time.

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