When the data on your WHOOP is not fully synced to your mobile device you may see the following message on the Overview screen of the WHOOP app, indicating that the data is still "catching up":
Note: WHOOP uses Bluetooth Low Energy (BLE) to transfer data to your mobile device, which means the WHOOP app must stay open in the background to continue transferring data and remain up to date.
The WHOOP 3.0 will continue to record and store up to 3 days worth of data. The WHOOP 4.0 can hold up to 2 weeks of data. Once your WHOOP reconnects, it will process the stored data.
Causes of data "catching up" on iOS and Android
Force quitting the app
Force-quitting the WHOOP app (for example: "Swiping" the app away in the recently used/multitasking view) will prevent WHOOP from running in the background, and data will not transfer until you relaunch the app.
Best practice: Leave the WHOOP app open in the background on your mobile device to ensure data continuously syncs.
Airplane mode may automatically toggle off Bluetooth and cellular data on your mobile device. Both are needed in order to sync data from your WHOOP to your mobile device. As long as WiFi is enabled and Bluetooth remains on, airplane mode will not have an impact on data syncing.
Bluetooth being off
Ensure that Bluetooth is turned on.
Best practice: Bluetooth should remain on at all times for optimal syncing.
Being out of Bluetooth range
When out of Bluetooth range, your WHOOP will become disconnected and data will no longer be able to sync to the app on your mobile device. Once you're back within range, you may see that your data is "catching up" until your WHOOP has fully synced with your mobile device.
Not having cellular service
Either WiFi or cellular data is required to send the data your WHOOP collects to our servers for processing. If you are out of cellular range, your data will be stored on the WHOOP 3.0 for up to 3 days. For WHOOP 4.0, your data will be stored for up to 2 weeks. Once the mobile device has re-established cell service, data will begin to upload again. At this point, you may the "catching up" message until your WHOOP has fully synced with your mobile device.
If the WHOOP battery drains completely, it will no longer be able to collect data. Once your WHOOP has been charged and reconnected, it will begin to collect and sync data again. You can double-tap the WHOOP at any time to check its battery life.
Power saving and low power mode
iOS: In your device's settings (the iOS Settings app), navigate to Battery. From here, ensure Low Power Mode is toggled off. If it is toggled on, it will significantly reduce how often the WHOOP syncs data with your mobile device.
Android: Power-saving mode can sometimes prevent the WHOOP app from running in the background. If this is the case, data syncing will be suspended until the app re-enters the foreground or power-saving mode is turned off.
iOS only: Background app refresh is off
In your device's settings (the iOS Settings app), navigate to General and select Background App Refresh. Find the WHOOP app in the list and ensure it is toggled on.
Android only: Battery optimization settings
Different Android devices abide by different battery optimization settings which can significantly limit background activity and Bluetooth activity. For specific phone settings, please refer to Frequent Android Disconnects.
How long will it take for my data to catch up?
The WHOOP 3.0 is able to hold up to 3 days worth of data. The WHOOP 4.0 is able to store up to 2 weeks worth of data. Depending upon how long it's been since it last synced with your mobile device, it may take some time for your data to catch up. For example, syncing a full day (24 hours) of data may take up to 1 hour.
If you are experiencing anything longer than this, please try rebooting your WHOOP following the steps below (no data will be lost when rebooting):
Inside the WHOOP app, tap on the status bar at the bottom of the Overview page (located underneath the health monitor overview) to open Device Settings.
The Device Settings screen will display an overview of your connectivity and battery status. Tap on the Advanced tab, and scroll through the menu options until you find the Reboot Device button.
Click Reboot Device and keep your WHOOP and mobile device close by for a few seconds until the reboot is complete.