ABSTRACT
This paper summarizes the data on external respiration and energy expenditures of men exposed to zero-g for 185 days and to 1/6 g on the lunar surface reported by Soviet and foreign authors. The paper also discusses factors that may be responsible for a higher level of gas exchange processes at reduced g.
Subject(s)
Energy Metabolism , Pulmonary Gas Exchange , Respiration , Space Flight , Weightlessness , Adaptation, Physiological , Extraterrestrial Environment , Humans , Time FactorsABSTRACT
The two members of the 140-day permanent Salyut-6 space flight were exposed to 5 LBNP tests at -25 and -35 mm Hg for 2 and 3 min, respectively. Circulation responses to the LBNP tests were measured with respect to the heart rate, arterial pressure, chronocardiogram and cardiac output. As compared to the preflight data, inflight responses were characterized by a greater tachycardia, preload insufficiency, and vascular tone in the absence of orthostatic intolerance. Possible mechanisms of the changes in the circulation responses are discussed.
Subject(s)
Decompression , Heart Rate , Hemodynamics , Lower Body Negative Pressure , Space Flight , Cardiovascular Physiological Phenomena , Humans , Male , Time Factors , USSRABSTRACT
During 140-day space flight body mass changes of the Commander and Flight-Engineer were measured. No correlation between body mass losses and flight duration was found. Greatest body mass losses occurred on MD 44--59 in Commander (2.3--2.4 kg), and on MD 86 in Flight-Engineer (5.4 kg). Later the losses decreased. The results suggest that body mass changes varied on an individual basis and depended on many spaceflight factors.
Subject(s)
Body Weight , Space Flight , Diet , Humans , Physical Exertion , Stress, Physiological/physiopathology , Time Factors , Water-Electrolyte BalanceABSTRACT
During the 140-day flight of the Salyut-6 station cardiovascular examinations were carried out at rest. They showed blood redistribution and hyervolemia of the upper body. They also demonstrated increases in the circulating blood volume and pulse blood filling of cerebral vessels, development of the phase preload syndrome and simultaneous decrease in blood filing of leg vessels. These changes varied phasically in the course of flight. Weightlessness of up to 140 days did not cause any pathologies in the cardiovascular system.
Subject(s)
Hemodynamics , Myocardial Contraction , Space Flight , Aorta/physiology , Blood Pressure , Blood Volume , Cardiac Output , Heart/physiology , Heart Rate , Humans , Male , Pulse , WeightlessnessABSTRACT
The purpose of the present investigation was to assess, using a specially built sensor, variations and level of fluid redistribution as well as atrophic changes in leg muscles of test subjects exposed to prolonged head-down tilt and cosmonauts in a real space flight. Hypokinetic test subjects were examined before, during and after head-down tilt, whereas cosmonauts were examined before and during flight. The results obtained show that a change in the hydrostatic component of blood pressure is followed by displacement of a substantial fluid volume (about 7%). Adequate performance of pre-assigned countermeasures seems to prevent atrophic developments of leg muscles.
Subject(s)
Body Fluids/physiology , Leg/physiology , Muscles/physiology , Space Flight , Humans , Leg/blood supply , Male , Movement , Posture , WeightlessnessSubject(s)
Cerebrovascular Circulation , Physical Exertion , Space Flight , Humans , Male , Plethysmography, ImpedanceABSTRACT
In 12 series of short-term (4.5 hour) experiments the exposures that influenced the blood distribution relative to the long axis of the body (postural changes, lower body excessive pressure, lower body negative pressure, axial loads) were studied. A close correlation between the blood flow in lung capillaries, water losses and orthostatic responses was established. The correlation was dysproportional when LBEP or LBNP was applied in certain postures. This may be attributed to the effect of these exposures on vessel compliance.
