Methods, devices, and systems for monitoring heart rate variability (HRV) are presented. The HRV monitoring systems and devices are adapted to give immediate feedback to the subject concerning their current condition and any pertinent changes in their condition. The HRV monitoring systems and devices detect, analyze, and assess HRV against a pre-determined application, user needs, against pre-determined limits, or user specific baselines or a combination of both pre-determined limits and user specific baselines. They also have the ability to provide real time notifications based on the systems assessment of a users heart rate, HRV and changes in the HRV.