As health sensors become more discreet, and fused with commonly worn devices, Kyocera has integrated a tiny, optical sensor into its earbud.  The hybrid music/phone/health use wearable measures blood flow in hypodermal tissues using Laser Doppler velocimetry. It can monitor nerve and blood pressure, levels of dehydration, and possible signs of heat stroke.  Sleep monitoring can be done more accurately than with current devices, and the effect of music on brain states can also be studied.