Blood pressure variability and frailty: mechanisms, evidence, and clinical implications.

Blood pressure variability (BPV), fluctuations in blood pressure across beat-to-beat, 24-h, day-to-day, and visit-to-visit timescales, has emerged as a risk marker that is independent of mean blood pressure. Frailty, a multidimensional syndrome of diminished physiological reserve, shares core biology with BPV, including vascular aging, impaired baroreflex function, autonomic dysregulation, and chronic low-grade inflammation. This narrative review synthesizes mechanistic, epidemiologic, and clinical evidence linking BPV and frailty. Mechanistically, arterial stiffness and endothelial dysfunction attenuate baroreflex buffering and transmit excess pulsatile load, while autonomic imbalance and inflammaging destabilize hemodynamics, compromise cerebral autoregulation, and promote sarcopenia and functional decline. Across cohorts of community-dwelling older adults and high-risk groups (e.g., chronic kidney disease and hemodialysis), higher short- and long-term BPV correlates with prevalent frailty and predicts incident frailty, cognitive decline, falls, cardiovascular events, renal progression, and mortality, often with effect sizes on par with traditional risk factors. Ambulatory blood pressure monitoring best captures short-term and circadian variability (including nocturnal patterns), home monitoring informs day-to-day variability, and clinic series quantify visit-to-visit variability; average real variability appears particularly informative in older hypertensive populations. Clinically, incorporating BPV into assessment may refine frailty screening and risk stratification, revealing vulnerability that is not apparent from mean blood pressure alone. Therapeutic implications include prioritizing long-acting antihypertensive regimens that stabilize BPV, optimizing adherence and lifestyle (exercise, diet, stress reduction), and addressing metabolic and inflammatory drivers, while recognizing that interventional evidence targeting BPV per se remains limited. Key gaps include heterogeneous BPV metrics and frailty definitions, limited standardization of measurement protocols, and a paucity of trials testing whether reducing BPV improves functional outcomes. Future work should not only harmonize BPV phenotyping and frailty definitions, but also investigate whether stabilizing BPV translates into tangible improvements in functional status, falls, and survival. Incorporating digital health tools, such as continuous monitoring and AI-driven analytics, may facilitate early detection of hemodynamic instability and its integration into frailty care models.