The claimed invention comprises software methods for user continuity and physiological state change assessments through generating biometric profiles of individuals and/or groups of individuals by using physiological input together with biomathematical modeling and machine learning techniques. Intra-individual variation in physiological variables including, but not limited to: heart rate, heart rate variability, pulse waveform and its derivatives, blood pressure, breathing rate, cardiopulmonary coupling, actigraphy and circadian rhythms characteristics, are exploited.
