Understanding Blood Pressure Variation and Variability: Biological Importance and Clinical Significance.

Variability is a normative property of blood pressure necessary for survival which likely contributes to morbidity and mortality through allostatic load. Because of its allostatic and adaptive properties blood pressure responses to peculiar situations like the visit to the clinic can lead to the misdiagnosis of hypertension. Cuff methods of blood pressure measurement can also create blood pressure variation when there really is none. There are also physiological differences between populations related to their evolutionary history that likely further affect the extent of population differences in 24-h blood pressure variability. Quantifying the sources and extent of blood pressure variability can be done using natural experimental models and through the evaluation of ecological momentary data. It is very likely that the results of population studies of blood pressure variability and morbidity and mortality risk are inconclusive because the parameters used to assess blood pressure variability do not reflect the actual nature of blood pressure allostasis.