Heterogeneity of blood pressure response to dietary sodium restriction in normotensive adults.

To investigate the effect of dietary sodium restriction on blood pressure in healthy, normotensive adults, 82 individuals (36 men, 46 women) participated in a study of restricted sodium intake (less than or equal to 75 mEq/day) for a period of 12 weeks. For the entire population there was a small but significant (p less than 0.01) decrease in mean arterial pressure during sodium restriction. The change in blood pressure was significantly correlated with age (r = 0.23, p less than 0.05). Division of the population at age 40, showed that the older individuals were more likely to have a decreased blood pressure during sodium restriction, while as a group younger adults showed no change. The individual blood pressure responses were heterogeneous with increases in pressure observed in some subjects. These results suggest that "sodium sensitivity" of blood pressure may be more evident with increasing age. Further, sodium restriction in all normotensive adults may not be innocuous.