About Sleep Rings & Quality.
AutoSleep 4 introduces a concept called Sleep Rings. You can think of these as the flip side to your Apple Watch's Activity Rings. Instead of filling them by moving, exercising and standing, you fill them simply by sleeping.
If you wear your Watch to sleep, then your sleep data will be represented by three rings.
☾ - Time Asleep
This reflects the time that you spent asleep. You fill this ring by sleeping enough hours to meet the sleep hour target that you set in the AutoSleep wizard.
% - Sleep Quality
This indicates the quality of your sleep. It is based on time slept, restlessness and heart rate. It's the most useful metric for monitoring how much quality sleep time you have had.
♥ - Average Heart Rate
This is your average heart rate during the time that you were asleep. The ring reflects the quality of the nocturnal dip in heart rate. This is measured as the percentage difference between your average heart rate when not engaged in physical activity and your average heart rate when sleeping. If you are interested in understanding more about nocturnal dip, there is an interesting study here.
On the Quality tab, there is a breakdown of each individual ring with a comparison to the trailing 7 days.
Z - Deep Sleep
There is also a fourth ring which provides the time spent in "Deep Sleep" and again compares this to the trailing 7 days. This time is determined by meeting a sufficient nocturnal dip in heart rate combined with minimal movement. Refer the "Profile" section below to change how this and the heart rate ring are displayed. The main value of this ring is to compare it against your own historical data rather than to other people.
Scrolling down further present the Sleep Quality Graph.
Here you will one graph per sleep session. A sleep session is defined as any period that you have been asleep with a break under 90 minutes in duration.
The blue graphics indicate the periods that you were asleep. The higher they rise, the more active you were.
The green graphics indicate periods in which you were awake.
The dots plot your heart rate during the time that you were asleep. Brighter dots indicate that the heart rate had a significant nocturnal dip (see heart rate ring above).
Periods of deeper sleep are shown as purple blocks. This is determined according your profile setting (below).
To deliver more relevant sleep quality analysis, the profile section is broken up into three types. These have an influence over the way the heart rate ring is represented and deep sleep is calculated.
This is the default. It is suitable for most people.
This is primarily to allow people that don't experience a nocturnal dip in heart rate to be able to reflect deep sleep. People with pacemakers, heart problems and lower levels of heart fitness should choose this option. It removes the requirement of nocturnal dip from deep sleep tracking and changes the presentation of the heart rate ring.