Well, to tell you the truth I don't know much about VR. I only think VR is what that is not real but you can experience it.
I don't know how it works either, for details you can visit the link.
It is a real time monitor of real performance that it presents in the form of colored feedback which would be very valuable for professional swimmers.
Instabeat is the only device with an accurate heart rate sensor
that shows you visual real-time feedback of your effort while you swim.