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Dynamic analysis of arterial blood pressure in relation to the Earth's magnetic field perturbations was performed in 77 practically healthy volunteers (staff of Bulgarian Academy of Sciences). Almost half of them proved magneto-sensitive, i.e. experienced AP elevation with increased geomagnetic activity. The probability of development of magnetic sensitivity was independent of age and gender but increased in volunteers having even mild cardiovascular pathology. These subjects complained of worsened health condition upon a rise in geomagnetic activity. However, some volunteers reported deteriorated well-being without AD elevation. It means that AD measurement may be insufficient for reliable monitoring magnetic sensitivity.

The course of different sleep phases has been studied in group of patients. A decrease in duration of deep sleep phase and increase in the number of awakenings are found in them.

In 40 aquanauts, a prolonged stay under increased pressure (11 to 46 kgs/cm2) of the oxygen-helium-nitrogen mixture did not affect the average duration of sleep. Slow-wave sleep, mostly its 3 rd and 4 th stages, and paradoxical sleep were significantly decreased whereas the light sleep/profound sleep ratio increased. The cyclic structure of sleep became altered. The longer the exposure to high pressure led to an augmentation of the slow-wave sleep and REM-phase, but the normal cycles terminating with a REM-phase could not be formed during the experiment.

Changes of amplitude-temporal parameters of visual evoked potentials (VEPs) under hyperbaric action testify to reconstruction of the activity of functional brain systems participating in the generation of responses to light stimulation. The revealed EP changes depend both on conditions of hyperbarism and on individual characteristics of subjects. The parameters of VEPs may manifest the estimation of common functional state under prolonged extreme influences.