Instant Heart Rate ^[1], a smartphone app that measures a user’s heart rate through the phone’s camera, has accumulated eight million downloads on iPhone and Android devices since its debut last fall. The creators of the app, Azumio ^[2], a start-up based in Palo Alto, California, announced today that it’s raised $2.5 million from investors, including Founders Fund, Accel Partners, and Felecis Ventures, to continue to deliver health-measuring mobile apps.

By distributing handy health applications like Instant Heart Rate to a much wider audience, Azumio has helped raise awareness around the potential of smartphones as biofeedback devices. Bojan Bostjancic, co-founder of Azumio, believes the smartphone will play an important role in helping improve people’s health.

“Mobile technology is fundamentally changing everything, including our approach to health,” he says. “We realized this would happen with this technology built into smartphones and we decided we wanted to provide a simple solution for bigger health problems.”

Companies are already devising ways to leverage smartphone technology, including the ability to retrieve and analyze big data from the cloud, to help diagnose illnesses and chronic diseases. According to Bostjancic, Azumio will use its investment money to expand its product line, which now includes two stress and treatment monitoring apps called Stress Check and Stress Doctor.

Read more from GigaOM ^[3].