BLOOD-PRESSURE 24-HOUR PATTERN IN 2 INDUSTRIALIZED COUNTRIES (ITALY AND JAPAN) WITH A DIFFERENT CULTURE IN SALT INTAKE

This study investigates the blood pressure (BP) 24-hour pattern in rep resentative samples of 2 industrialized countries, Italy and Japan, sh owing different cultures in salt intake. BP was monitored by means of a noninvasive ambulatory device whose readings were analyzed by means of chronobiometric procedures. The results show that the 24-hour BP pa ttern is not substantially different in Italian and Japanese subjects. In particular, the expected lower BP in the Italians was not detected despite their lower salt intake. Because the 24-hour mean BP value wa s seen not to be proportional to salt intake, the hypothesis is formul ated that maintenance of the pressure regimen within a given range of variability is a principle of human physiology. To comply with this ru le the Japanese people are supposed to have ethnically developed a cer tain resistance to dietary salt for which their cardiovascular apparat us is protected (phyletic escape to dietary sodium excess).