[Changes in various indicators of orthostatic stability in humans on long-term low-caloric diets]

Ten male volunteers received a low-caloric diet (LCD) (under 1200 kcal) containing 49.4 g protein, 28 g fat and 181 g carbohydrates for 3 weeks, with energy expenditure amounting to about 2900 kcal/day. During the time indicated, the body mass of the test subjects dropped by 7.1%. According to subjective data the well-being, physical and mental working ability remained unchanged in the test subjects. During feeding with the LCD and making the active orthostatic test, the increment of the heart rate upon the change of the body position appeared the same as that during the comparison period. Meanwhile on the 6th day of the recovery period the increment was significantly higher than at the comparison period. The systolic, pulse and mean arterial pressure, with the test subjects fed the LCD being in the vertical position and at the recovery period, was lower than at the comparison period. The data obtained attest to a definite lowering of the orthostatic stability of man kept on the LCD for a long time and at the recovery period, with this lowering taking place chiefly at the expense of changes in the tone of peripheral blood vessels.