Portable device and method for measuring heart rate

A method for improving the physiological coherence of a subject using a portable electronic device, the method comprising the acts of:

• receiving pulse data from a subject;
• determining a power spectrum distribution of the pulse data,
• determining a heart rate variability waveform based on the pulse data having a power spectrum distribution (PSD);
• determining a coherence level for the subject derived from a PSD peak of said PSD;
• tracking the PSD peak of the PSD, wherein the PSD peak has an amplitude and frequency which vary over time;
• providing a coherence indication representative of the coherence level of the subject;
• and
• prompting the subject to breath at a desired respiration frequency which is associated with an increased coherence level.

A portable electronic device comprising:

• a pulse sensor;
• a coherence indicator;
• a respiration indicator;
• and
• a processor, electrically coupled to the pulse sensor, coherence indicator and respiration indicator, said processor configured to:
• receive pulse data from the pulse sensor corresponding to a user,
• determine a power spectrum distribution of the pulse data,
• determine a heart rate variability waveform based on the pulse data having a power spectrum distribution (PSD),
• determine a coherence level for the user derived from a PSD peak of said PSD,
• track the PSD peak of the pulse data PSD, wherein the PSD peak has an amplitude and frequency which vary over time;
• provide a coherence indication representative of the coherence level of the subject using the coherence indicator, and
• prompt the subject, using the respiration indicator, to breath at a desired respiration frequency which is associated with an increased coherence level.