iHeart Internal Age readings are a measure of Aortic Pulse Wave Velocity (AoPWV).  AoPWV is widely used by medical scientists to determine Aortic Stiffness. Aortic Stiffness is a powerful health indicator that is well accepted to predict risk of death from all causes. Aortic Stiffness is a single physiological parameter that is uniquely able to provide an assessment of overall health and estimate lifespan. Internal Age is your age physiologically as compared to your chronological age.AoPWV is influenced by both Aortic Stiffness and Blood Pressure (BP). Variation in BP is the factor leading to variability in iHeart Internal Age values. By understanding how to control for BP effects, your iHeart readings will be more consistent and will more effectively show benefits of making healthy lifestyle choices.iHeart performs precise analysis of the fingertip arterial pulse signal to find and characterize a wave that travels down the Aorta and then reflects back towards the heart and continues onward to the arm, forearm and finger.