[Characteristics of the functional state of the nervous system of middle-aged persons during anti-orthostatic hypokinesia].

The functional state of the nervous system and its autonomic compartment was investigated in 15 men, aged 40-52 years, during their 30-day exposure to head-down tilt (-8 degrees). Group 1 consisted of 9 subjects with early manifestations of cerebral atherosclerosis and Group 2 included 6 subjects with cerebral atherosclerosis and arterial hypertension. The control group incorporated 9 healthy volunteers, aged 25-39 years. During adaptation to head-down tilt, middle-aged and young subjects showed consistent changes in the nervous system. In response to perturbation effects, autonomic reactions were inert and autonomic support was excessive. However delayed onset of responses, duration and slow recovery of the parameters examined indicated that mechanisms of autonomic regulation were inadequate. These changes were most distinct in middle-aged subjects, particularly in Group 2 subjects: recovery of the functional state of the nervous system was completed by day 20 in middle-aged subjects and by day 9 in young subjects. The observations have demonstrated that the nervous system of most middle-aged subjects (taking into consideration age-related and atherosclerotic changes) has a sufficiently high level of functional capabilities during medium-duration head-down tilt studies.