There are several sleep trackers that use actigraphy, or body movements, to estimate sleep onset and duration. Actigraphy is often measured with sensors embedded in a watch or bracelet, or even your iPhone. Any tracker that involves placing your iPhone on your bed to measure sleep is using actigraphy. With actigraphy, the basic assumption is that if you are moving more, you are awake, and if you are moving less, you are asleep. This technique works reasonably well in healthy individuals. With individuals suffering from insomnia, however, these devices are significantly less accurate. This makes sense if you consider that individuals with insomnia may lie awake with their bodies relatively still but their mind racing! A sleep tracker using actigraphy will likely classify these periods as sleep although the person is actually all too awake. In summary, accelerometers overestimate total sleep time, and are even less accurate when measuring the sleep of individuals suffering from insomnia.
Sleeprate instead uses heart rate variability to assess sleep. This method is more accurate than actigraphy, and has the added benefit of being able to detect increases in hyperarousal, which are associated with chronic insomnia. This means that with ongoing monitoring, an upcoming period of insomnia could be prevented before it even starts. It turns out that several major consumer sleep trackers are beginning to use heart rate. It should be noted, however, that none of these sleep trackers have been validated against PSG measures, and even sleep scientists are not sure whether they are accurate. Currently, a validation study for Sleeprate is underway involving hundreds of patients in a sleep clinic who will be monitored in an independent sleep laboratory using Sleeprate. Importantly, an optional sleep improvement service creates treatment plans tailored to each individual; these provide cognitive and behavioral strategies shown to be effective for reducing hyperarousal and improving sleep by numerous, independent scientific studies.
Most importantly, Sleeprate will customize a sleep improvement program for you, based on your sleep data, so that you can ensure you are getting healthy, refreshing sleep.