A review of the literature suggests that blood pressure (BP) is multifactorial and is affected by the interactions of genetics, physiology, responses to the environment, and lifestyle factors that have increasing influence as one ages. The effect of these factors on hypertension (HTN) risk as one ages is depicted in the author's Hypertension Risk Model. The model emphasizes HTN risk in the older adult--age 50 and older--and shows the interaction of the factors influencing HTN development and BP assessment methods. Implications of three methods of BP assessment--(1) static BP, (2) 24-hour ambulatory blood pressure monitoring, and (3) clinic blood pressure reactivity (BPR) protocol--are discussed. The model may be useful for understanding factors that contribute to HTN and for guiding BP assessment for clinical researchers. Addressing the factors associated with the sympathetic system activity from various environmental stressors requires assessing dynamic BP, particularly in the older hypertensive adult who has increased BPR. Further research should focus on ambulatory blood pressure studies in older adults that would provide the methods and instrumentation needed to assess HTN and therefore decrease mortality and morbidity in this population.