Evolution of blood pressure regulation in humans.

The human propensity for hypertension is a product, in part, of our evolutionary history. Adaptation to climate, first in Africa and then throughout the world, has driven our evolution and may have shaped current patterns of hypertension susceptibility. This article reviews human evolution and the impact of climatic adaptation on blood pressure physiology. Evidence suggests that genetic susceptibility to hypertension is ancestral and was magnified during early human evolution. Furthermore, differential susceptibility among human populations is due to differential selection during the out-of-Africa expansion 30,000 to 100,000 years ago. The most important selection pressure was climate, which produced a latitudinal cline in hypertension susceptibility. Therefore, the current epidemic of hypertension is likely due to new exposures of the modern period (e.g.: higher salt intake) interacting with ancestral susceptibility. Worldwide populations may differ in susceptibility to the new exposures, however, such that those from hot, arid environments are more susceptible to hypertension than populations from cold environments.