1. A highly significant correlation between intralymphocytic sodium concentration and basal diastolic blood pressure can be found only in patients with sustained essential hypertension.
2. In subjects with borderline hypertension and in normotensive subjects with familial hypertension a highly significant correlation can be found between intralymphocytic sodium concentration and the increase in diastolic blood pressure induced by mental arithmetic or handgrip exercise.
3. The increase in diastolic blood pressure recorded during mental arithmetic and handgrip in patients with borderline hypertension and in genetic normotensive subjects is significantly greater if intralymphocytic sodium concentration is greater than 26 mmol/kg.