Hypertension: the sodium connection.

It appears from epidemiologic, population, and individual studies that sodium is capable of raising blood pressure and its attendant cardiovascular complications in susceptible individuals. Potassium loss occurs with sodium loading and may modulate the blood pressure responses to sodium. Populations known to be at greater risk for the development of hypertension and its cardiovascular sequelae, such as blacks, older individuals, and those over the age of 40 years are also known to be less efficient in handling sodium. Furthermore, they are more apt to be sodium-sensitive than -resistant. The phenomena of sensitivity and resistance, demonstrable in both normotensive and hypertensive individuals, can be identified by rapid sodium and volume loading and depletion as well as by modest reduction in dietary sodium intake. Finally, preliminary evidence suggests that sodium sensitivity may be predictable by genetic markers as well as by demographic characteristics.