Aidlab has an internal, flash memory storage. Depending on its version (you can view the available variants here), it can store up to more than six hours of data.
So, if it is not within range of an iOS or Android device, data is temporarily stored on the Aidlab and uploaded later, when your smartphone is back in range. That means you can go for a run or to the gym without carrying your smartphone - just switch your Aidlab on and it’ll start recording and saving the data automatically.
Syncing times can take a few minutes up to multiple hours, so please be patient. It depends on the size of your flash capacity and the time you spent collecting data without connecting to your phone. There’s not a great way to forecast how long a sync is going to take.