Say you wear an Apple Watch to bed, and a Fitbit on the other wrist. Both record your night. The watch writes it to Apple Health, the Fitbit writes it to Google Health, and Voke reads both.
If Voke added them up, you’d have slept fourteen hours. Here’s what it does instead.
One night, one source
Voke keeps a list of your sources in order, and it keeps that order separately for each kind of data: sleep, heart, activity, workouts and so on.
When two sleep records overlap, Voke keeps the one from the source that’s higher on the list and drops the other. It doesn’t blend them. You don’t get the watch’s bedtime with the Fitbit’s wake time, or stages stitched together from both. The night you see is one device’s night, as that device recorded it.
Workouts work the same way. If both devices log the same run, the higher-ranked one stays and the other is set aside.
How the order is set
The order comes from a few plain rules, checked one after another:
- What kind of device it is. Things you wear, like a watch, ring or band, come first. Then a scale or blood pressure cuff. Then your phone. Then apps where you typed something in.
- How the data got to Voke. A source Voke reads straight from where it was recorded beats a copy that another app passed along. If the Fitbit app also copies your night into Apple Health, Voke reads the same night twice, once from Google and once through Apple Health. The one from Google wins, because it’s the original.
- A fixed tie-break. When two sources are still level after that, Voke breaks the tie by the maker’s name and then the model. It says nothing about which device is better. It just keeps the answer the same every day.
So with an Apple Watch and a Fitbit, both are worn devices, and both are read directly. The tie-break decides, and today that puts the Apple Watch first.
Minute by minute, the gaps get filled
Heart rate and steps are readings, roughly one a minute, so Voke makes the choice for each minute on its own.
For every minute, Voke takes the reading from the highest-ranked source that has one, and only that reading. Two sources counting the same steps in the same minute never get added together.
The upside is that a gap in one source can be filled by another. Say your watch is on the charger for an hour in the evening. Your phone was still in your pocket counting steps. For that hour, and only that hour, the phone’s steps count. Before and after, the watch’s steps count, and the phone’s are ignored.
Yesterday
Monday, October 5Sunday
October 4Which day a night belongs to
A night that starts at 11 PM Sunday and ends at 7 AM Monday belongs to Monday, the day you woke up. That’s where it shows in the Feed, and that’s the night your Monday scores are worked out from.
To pick the main night for a day, Voke looks at the sleep that ends between 3 AM and 3 PM local time, and takes the longest one that the source hasn’t marked as a nap. That’s the main night.
How a nap is told apart from the night
Then Voke decides which of the other sleeps that day are naps.
A sleep is a nap when it isn’t the main night, doesn’t overlap it, and either:
- the source says it’s a nap, or
- it starts after the main night ended.
Google Health marks naps itself. For Apple Health, Voke counts a sleep as a nap when it’s shorter than three hours and starts between 9 AM and 7 PM.
Sleep before the main night is never a nap. If you fell asleep at 12:30 AM, woke at 1:30, and slept again from 2 until 8, that first stretch isn’t counted as a nap.
On a day with no main night at all, a sleep counts as a nap when it ends after 3 PM.
Naps get the same treatment as nights when two sources record one. If your watch and your Fitbit both catch the same afternoon nap, Voke counts it once.
A nap’s length is the time you were actually asleep, when the source sends sleep stages. When it doesn’t, Voke uses the whole span.
Naps don’t change the night
A nap shows in the Feed as its own entry, at the time it happened. It never changes your main night: not its length, not its scores. If you slept five hours and then napped for one, Voke shows a five hour night and a one hour nap, not a six hour night. Whether that nap costs you sleep the next night is another question, covered in do naps hurt your night’s sleep?
If you share sleep with someone at the daily totals level, they see how long you napped that day and nothing more. The nap itself, with its times and stages, is only shared at full detail, the same as the night.
What we haven’t done yet
You can’t change the order of your sources from inside the app yet. For now Voke uses the order described above for everyone.
If you think Voke picked the wrong night, or counted a nap that wasn’t one, tell us.