Memory full, fifo error

maybe this is expected behavior from the health app collecting data or something like this?

No, it's definitely not... Maybe the first few minutes it might lose something, but after a few minutes no new memory should be getting used.

If you want to try and debug it yourself, you can do E.dumpVariables() (you'll have to enable logging via the IDE as it dumps a lot of stuff) then wait until the free memory goes down by a chunk, run it again, and 'diff' the two sets of data you get.

It might give you some clue (based on variable names) as to what's using the memory