[Brain blood circulation and oxygen supply in the healthy human being during measured physical loading in a head-down tilt posture]. / Krovoobrashchenie i kislorodnoe obespechenie mozga zdorovogo cheloveka vo vremia dozirovannoi fizicheskoi nagruzki v antiortostaticheskom polozhenii.

Eleven healthy male test subjects performed exercises of 600 kgm/min (98 W) for 20 min in the head-down position (-15 degrees). A day before exercises they were catheterized, with catheters implanted into the internal jugular vein and brachial artery. It was shown that exercises in the head-down position led to an increase in cerebral circulation, a decrease in oxygen utilization and a decrease in jugular pressure. CO2 tension in arterial blood and blood outflowing from the brain remained comparatively stable, while base deficiency and buffer capacity decreased by a similar value.

[Coronary circulation in healthy men during postural changes and decompression of the lower half of the body]. / Koronarnoe krovoobrashchenie zdorovogo cheloveka vo vremia postural'nykh vozdeistvii i dekompressii nizhnei poloviny tela.

The effect of postural changes (ortho- and antiorthostatic tests) and LBNP on coronary circulation was investigated in 11 healthy male test subjects. Volume blood flow velocity and pressure were measured and blood flowing from the heart was withdrawn using a Ganz catheter implanted into the coronary sinus. A thin Teflon catheter was implanted into the brachial artery. When the test subjects were transferred from the recumbent to the head-up position, their left ventricular oxygen consumption decreased by 3.2 ml/min (21%) and coronary blood flow by 23.8 ml/min (19%), while coronary vascular resistance increased by 32%. When the test subjects were transferred from the head-up to the head-down position (at -15 degrees), coronary oxygen consumption and blood flow increased by 5.5 (46%) and 45.3 (44%) ml/min, respectively, and coronary resistance decreased by 36%. In this situation the LBNP test (-30 mm Hg for 20 min) caused a reduction in oxygen consumption and coronary blood flow by 4.4 (25%) and 37.3 (25% 7 ml/min, respectively, and an increase in coronary resistance by 58%.

[Comparative evaluation of pressure chamber training and high altitude adaptation to hypoxia in humans]. / Sravnitel'naia otsenka barokamernoi trenirovki i vysokogornoi adaptatsii cheloveka k gipoksii.

It was demonstrated that a 3-day pressure chamber training may increase the maximum tolerable "altitude" at rest from 8,600-8,900 m (depending on the onset rate of hypoxia) to 9,600 m. After pressure chamber training the maximum tolerable "altitude" increased from 8,200 m to 9,200 m, when exercising in a bicycle ergometer at 200 kgm/min and continuously ascending at a rate of 20 m/sec. A similar antihypoxic effect was also provided by a 7-day high altitude adaptation. Using polarographic measurements of oxygen tension in the skin, it was found that adaptation to hypoxia induced a more pronounced oxygen decrease at high altitudes. This can be attributed to a more distinct blood redistribution, i. e., a better blood supply to the vital organs at the expense of peripheral tissues.