Camera Heart Rate Variability is the first app that lets you record, plot and export time and frequency domain Heart Rate Variability Features (as well as heart rate and RR intervals), without requiring any heart rate monitor.

Main Features:
- extracts, plots, stores and exports heart rate, rr-intervals, time and frequency domain heart rate variability features (AVNN, SDNN, rMSSD, pNN50, LF, HF, LF/HF)
- configurable time window for feature extraction (30 seconds to 1 minute)
- automatic RR-interval correction
- data export/storage on Dropbox or via email (csv format, exports rr intervals, and computed features).

Find out more at this link: http://www.marcoaltini.com/2/post/2014/01/heart-rate-variability-using-the-phones-camera.html