Well it's really a patent for a method which includes both software and hardware (the sensors). It still might be an Art 84 rejection but I don't know enough about the EPO to say. They haven't filed any international patents, though, so it would not at all be enforceable in Europe even if it was patentable subject matter.
The sensors themselves are nothing special, the first patent was filed for a standard Android smartwatch. There is no new hardware, it's just an algorithm for a software system that happens to talk to hardware.
In the USA it's an improvement patent (see 35 U.S.C. 101). Because the algorithm is novel and involves steps that rely on hardware, you can patent the combination of hardware and process. Not sure if Europe views it the same way.
