Both excess weight and hypertension may contribute independently to increased risk of cardiovascular disease. Weight and blood pressure have been found to be associated in most studies in diverse populations. The increase or decrease of blood pressure with weight gain or loss suggests a causal relation, although the mechanism is uncertain. A correlation between blood pressure and weight can be identified early in life. This correlation coefficient increases to approximately 0.4 in young adults and then begins to decrease at older ages. It is likely that weight interacts with various factors controlling blood pressure at different points over a lifetime. The implications for prognosis or control of blood pressure at different ages may vary as well. Attention to minimizing weight gain at a particular period of life, such as in young adulthood, might have long-term beneficial effects in preventing subsequent hypertension or excess blood pressure increase with aging.