Sleep monitoring can reveal much more information about our health and physical condition than we might suspect. A doctor’s typical questions, “How many hours do you sleep each night?” and “How often do you get up to go to the bathroom in the night?” glean only the basic information. Sleep duration remains a significant concern because so many of us don’t get enough rest at night. Beneath the highest level of sleep quantification, however, lies a rich layer of additional information.

Emfit Limited’s Emfit QS monitors heart rate variability throughout the night or any other period of sleep. The device measures ballistocardiography to create a graphical representation called a ballistocardiogram of the ballistic forces on the heart. The graph shows the repetitive motions of the body that results from the sudden ejection of blood into the great vessels of the heart with each beat.

The Emfit QS sensor tucks under the mattress placed under the general location of the sleeper’s heart. A cord extends from the sensor to a WiFi transmission pod and then to power plug. The signals sent from the Emfit QS measure heart rate, heart rate variability, breathing rate, and movement. This data, represented by a ballistocardiogram, can be viewed on a smartphone, tablet, or computer. According to Emfit, the data can be used for stress analysis, sleep stages, exercise recovery analytics, and to detect sleep apnea. Remote caregivers can also monitor patient’s sleep.

According to Emfit, the monitor’s sensitivity detects a single grain of rice dropped on a mattress. A 2014 study published by the National Institutes of Health, reports that devices based on ballistocardiography were dismissed in the 1980s and 1990s, but are now worth revisiting for monitoring purposes in clinical and home settings. Improvements in sensor sensitivity and computer data analysis, such as with the Emfit QS, could have merit for monitoring and trending applications.