[Clinicophysiological changes in the human body during prolonged head-down tilt hypokinesia]. / Kliniko-fiziologicheskie izmeneniia v organizme cheloveka pri dlitel'noi antiortostaticheskoi gipokinezii.

By clinical-physiological and biochemical methods adaptation to prolonged (182 days) head-down tilting (--4.5 degrees) was investigated. It was found that man exposed to hypokinesia for a month or longer, with countermeasures lacking, showed polymorphic clinical-physiological and biochemical disorders accompanied by a decline of his adaptive capabilities. This may aggravate further adaptation and readaptation processes.

[Comparative evaluation of studies of the action of different levels of hypoxia on the human immunobiological status]. / Sravnitel'naia otsenka issledovanii deistviia razlichnogo urovnia gipoksii na immunobiologicheskii status cheloveka

The effect of hypoxic hypoxia on the specific factors of immunity of 16 test subjects was studied during their 30-day exposure to an altitude of 2100-4200 m above the sea level in the area of the Elbrus mountain. In order to differentiate the effect of hypoxia per se from that of other factors typical of highlands, five runs of altitude chamber experiments were carried out. In each run the test subjects were 10 times lifted to altitudes of 3200 m, 4200 m and 5200 m. The chamber experiments were performed on 28 test subjects, aged 26-46. During an exposure to an altitude the test subjects did two or three times exercises of 450-900 kgm/min on a bicycle ergometer. The experimental findings show that hypoxic hypoxia brings about consistent changes in the immunobiological status of man that are directly correlated with the level of hypoxia. These changes include a decline in the acquired antiviral and antitoxic immunity activation of the autoimmune process and an increase in the phagocytic activity of neutrophils. Our results suggest optimal profiles of the hypoxic effect to which test subjects should be exposed during mountain training for a specific occupational activity.

Effect of antiorthostatic bed rest on the human body.

Head-down (-4 degrees) bedrest brings about a more rapid development of changes in haemodynamics, fluid displacement and nervous tone than traditional recumbent bed rest. Changes occurring during head-down hypokinesia have much in common with the changes typical of real weightlessness. They are characterized by phasic changes in the vascular tone. Under these conditions changes in the tone and blood-filling of the brain are important for the functional state of the vestibular apparatus.

A study of the cumulative effects of repeated exposures to radial accelerations.

After exposure to transverse accelerations of 4-10 g changes in the vascular system of the eye and immunobiological resistance of the body persisted from 5 to 15 days. The data give evidence that the state of retinal vessels is the most informative index of the cumulative effect on the body and its recovery.