Standland uses data from the app and Apple's Health app.
You can save these data by backing up with iCloud and Finder on your Mac (requires encryption). And you can restore your device from the backup.
If you choose Finder on your Mac for backup, you need to turn on the "Encrypt iPhone backup" option.
More information: About encrypted backups on your iPhone, iPad, or iPod touch
We recommend doing an encrypted backup with Finder on your Mac. This backup includes certain information that other backups don't.