Blood pressure variability is the dynamic fluctuation of arterial blood pressure over time. As a central concept and research area within cardiovascular physiology and clinical medicine, it involves the systematic investigation and quantitative analysis of these temporal variations across different timescales, including beat-to-beat, short-term, and long-term periods. This field examines the patterns, magnitude, and determinants of blood pressure changes, recognizing its significance as an independent factor associated with cardiovascular events, target organ damage, and prognosis, distinct from average blood pressure levels.