"The Forerunner 10 is our lightest, most comfortable running watch yet, and it comes with our trusted accuracy and reliability, " said Dan Bartel, Garmin's vice president of worldwide sales.

ENGADGET: Garmin Forerunner 10 is a GPS watch designed for outdoor fitness, we go hands-on

Ms. Swan acknowledges that citizen scientists need to start running trials with much larger numbers of people to insure better accuracy.

WSJ: Citizen Scientists Take On the Health Establishment