This could be another solution for HR Monitoring for Run.Gps.
"Swiss company CSEM has created the Pulsear device to monitor ones heart rate while exercising. Pulsear uses a tiny unit embedded in a regular earphone to see how fast the pulse is by sending the infrared signals through the tissues in your ear. The result is shown on an iPhone. Pulsear is based on space technology developed to examine how astronauts will behave during long space voyages.