[Dynamics of the integrated characteristics of heart rate variability and psychophysiological parameters of students under the conditions of daily and weekly academic loads].

The effects of daily and weekly academic loads on the psychological and cardioand hemodynamic characteristics of students were analyzed. The self-estimated state of health, activity, and mood were evaluated with the use of the HAM (Heallh-Activity-Mood) questionnaire; the introversion and extraversion, neuroticism, and intelligence of the subjects were determined according to Eysenck; and the self-estimate the personal anxiety according to Spielberger, was evaluated. The main hemodynamic parameters (heart rate and arterial blood pressure) were measured and the systolic and minute blood volumes were calculated. The comparison of the dynamics of the parameters studied showed that there were two types of response of the students' cardioand hemodynamic parameters to academic load: sympathetic and parasympathetic. The parasympathetic response was found to be more adequate because the sympathetic response entailed the risk of overstrain and adaptation failure. DOI: 10.1134/S0362119706040074 INTRODUCTION Scientific and technological progress has substantially affected population structure. The relative number of jobs involving mental work has increased. Different types of mental work differ from one another in the organization of work, homogeneity of load, and degree of nervous and emotional strain. Studying is one such type of work. Studying requires efforts of memory, attention, and reasoning because students are constantly perceiving and processing large amounts of new information. Mental work is accompanied by numerous functional changes in the nervous, endocrine, cardiovascular, and other systems. University and college students form a large group of persons engaged in mental work that has some specific features. Published data [1-4] indicate that students' mental work is characterized by a large, irregular load, which leads to disturbances in the regimens of rest and eating. This results in overfatigue and a decrease in the learning capacity expressed as a decrease in academic success and may eventually cause adaptation failure and pathological changes in the body. There is evidence [5,6] that the prevalence rate of central nervous system (CNS) disorders and neurogenic diseases is high in students. The strain of physiological systems peaks during the examination period [3, 4, 7, 8]. However, this period is too short to be the only factor determining negative effects on the functional states of students' bodies. We analyzed the changes in psychophysiological, cardiodynamic, and hemodynamic characteristics caused in students by academic load in the daily and weekly METHODS Thirty female students of the Faculty of Biology of Yerevan State University aged 19-20 years were the subjects of the study. Integrated psychological testing of the subjects was performed preliminarily. Personal anxiety was evaluated according to Spielberger; the self-estimated state of health, activity, and mood were estimated using the HAM questionnaire; a special test form was used to determine the subjects' self-estimates; and Eysenck's questionnaire was used to differentiate between extraverts and introverts, estimate the degree of neuroticism, and divide the subjects into four groups according to the main types of nervous activity (choleric, sanguine, phlegmatic, and melancholic temperaments). We measured the main cardioand hemodynamic parameters: heart rate (HR); arterial blood pressure (BP), including the systolic (BPS), diastolic (BPd), pulse (PP), and mean dynamic (MDP) pressures; and respiration rate (RR). The BP was measured by the method of Korotkoff. Starr's equation was used to calculate I he systolic and minute blood volumes (SBV and MBV, respectively). Electrocardiograms (ECGs) were recorded using standard lead I, the subjects sitting with their eyes open in a screened half-darkened room. An IBM PC 486 was used to record 2.5-min ECGs and process the records. A sample of 100 cardiointervals was obtained for each subject. The mathematical analysis of HR was performed using variation pulsimetry according to the criteria proposed by Baevskii et al. [9]. For this purpose,