Clinical review
Free version: 
Paid version:
Reviewer: Dr Jeremy Steinberg, GP
Date of review: April 2018
Comments: This app is useful for people with insomnia who would like to record a sleep diary. It can enable them to assess insomnia treatment effects and night to night variations in sleep.
The type of algorithm that this app uses to track sleep is called actigraphy. This determines wakefulness based on movement patterns. It is important to note that it isn’t as accurate as the gold standard polysomnography. Actigraphy is particularly inaccurate for those with very poor sleep, restless legs and who have minimal activity during times of wakefulness, and in these cases I would not recommend the use of this app. Actigraphy can also over-detect times of wakefulness compared to a manual sleep log which could cause anxiety.
I would probably recommend doing a manual sleep log rather than using this app. However, if this was too difficult or the motivation to do this was lacking then the app could be trailed, but I would recommend first comparing it to a manual sleep log after using both for a few days. If the app was going to be used, then one could look at treatment effects and night to night variability.
Another feature of this app is the “smart-alarm” which claims to wake you up during non-REM sleep and thereby improve the wakening experience. This would depend on the apps ability to detect one’s sleep cycle which has not been demonstrated in research (detecting sleep cycles needs tracking brain waves), and the so called “90-minute sleep cycle” is a bit of a myth. In addition, the concept of a “smart-alarm” improving the alertness at the time of wakening has not been proven, and there is limited research that refutes this hypothesis. Personally, I felt less awake when using this feature.
Overall, technically it is a quality app. However, I am uncertain if those with insomnia would get much benefit from its use and was overall quite gimmicky. For the main user group that the app targets – those with poor sleep – actigraphy is not very accurate. I am surprised that despite the popularity of the app and the huge breadth of features that the developers have not published any research assessing its effectiveness.
Safety concerns: None.
