That doesn’t make sense though: the article says they exported data for the same time period months apart and it was different. That means either the raw data is stored, or the preprocessing they do is non-destructive so they can undo it to re-process it when the algorithm changes.Because of memory constraints, I bet they don't store the actual data stream coming off the sensors. Rather the software on the watch pre-processes the data. Perhaps the Apple Watch has a streaming mode that is accessible to apps on a connected phone. I know some Samsung watches have this.
Last edited: