Background and aim: Subjective symptoms of Internet addiction (IA), such as interpersonal and health-related problems (IH-RP), do not correlate with objective physiological parameters. This study aimed to investigate the cardiovascular reactivity after physical exercise in 15–16-year-old adolescents showing different severities of symptoms of health-related problems due to Internet overuse.Methods: This study included 20 healthy adolescents (boys, 15–16 years) with different risks of IA (by the Chen internet addiction scale [CIAS]). The physical exercise test was to perform a standing broad jump three times. The arterial blood pressures and heart rates were recorded before, immediately after, and at 4 minutes of rest after exercise.Results and discussion: The total sample of adolescents was divided into two groups, that is, those with IH-RP scores of 12 or less (Group I, n = 12) and those scoring more than 12 points (Group II, n = 8). The diastolic blood pressure significantly increased after exercise in group II, whereas it remained stable in group I. The heart rate in group I tended to increase, but the changes were not statistically significant. Group II adolescents showed significant increases in heart rate, and at rest, this parameter was significantly higher than the baseline value.Conclusions: Adolescents with a risk of IA and severe symptoms of interpersonal and health-related problems had increased sympathetic activity during and after speed-strength physical exercise compared to those without the aforementioned symptoms.

An individual analysis of long-term monitoring of microcirculation parameters of nine healthy volunteers showed that an increase in the geomagnetic activity led to an increase in tissue perfusion, variability of blood flow and growth of the amplitude of neurogenic and myogenic oscillations in four volunteers. It was found that the degree of microcirculation sensitivity to the level of geomagnetic activity varies with time and is proportional to its average level in the period of measurement. A comparison of frequency ranges of oscillations of blood flow and variations of the geomagnetic activity shows that neurogenic and myogenic oscillations showing the highest sensitivity to the geomagnetic activity have the same frequency as geomagnetic Pc3 pulsations. The pulsations of this frequency range are excited mainly during geomagnetic disturbances, which may explain the correlation between the microcirculation parameters and the K _p-index. The relation of the amplitude-frequency characteristics of Pc3-pulsations can explain the results obtained using Lednev’s model which treats the spins of hydrogen nuclei as a primary target of action for extremely weak alternating magnetic fields.

Internet-dependent behaviour in adolescents can contribute to a change in the function of the nervous system, which is reflected in the violation of time perception and autonomic regulation of the heart rate. The aim of the study was to determine groups of individuals with different risks of Internet addiction (IA) in relation to heart rate variability (HRV) parameters and the efficiency of time estimation in adolescents aged 16–17 years living in the Russian Arctic. Adolescents aged 16–17 years (n = 49–32 females, 17 males) living in Yamalo-Nenets Autonomous Okrug (Russia) were observed. Chen Scale Internet Addiction (CIAS) was used. The duration of an individual 1 min was determined. HRV parameters were determined using the "Varicard" equipment (Russia). In 16–17-year-old adolescents with different levels of risk of developing IA, including signs of IA, we revealed a high severity of symptoms of withdrawal from Internet use, difficulty in time estimation against the background of sympathicotonia and a decrease in vagal regulation of heart rate. In individuals with minimal symptoms of withdrawal from Internet use, the total HRV and vagal activity remain higher than in those with severe withdrawal symptoms, and their time estimation remains effective.

INTRODUCTION: The aim of the work is analysis of one of the most important problems of the modern biomedical science problem of studying the processes of human adaptation to a complex of climatic and geographic factors and conditions of the Far North in the period of increased necessity in realization of the economic, industrial and defense activity of the government. The review presents the data of scientific study of cognitive functions and neurophysiological changes in people permanently living in or arriving to the Arctic zone. In the first part, the factors are considered that evidence different disorders in memory, concentration, efficiency of performing simple and complex cognitive tasks by test persons in conditions of low temperature, seasonal photoperiodicity, a particular working regime, such as rotational team method, etc. The age-related peculiarities of dynamics of the cognitive processes in children and adolescents living in the Arctic region are considered. The second part of the article presents analysis of scientific data on changes of electrophysiological parameters of the brain structure activity under the influence of individual or complex factors of Arctic conditions. In particular, changes of the encephalographic rhythms, evoked potentials, hemispheric asymmetry and parameters of autonomic regulation of the heart rate variability in the initial condition and on exposure to the factors of the Far North, are described. A necessity of individual typological analysis of the adaptation process characteristics depending on the initial regulatory peculiarities, neurophysiological characteristics of people, duration of their stay in the mentioned conditions, is emphasized. Inconsistency or ambiguity of the presented data indicate the importance of using a complex approach to scientific research which should include systemic analysis of the dynamics of neurophysiological characteristics and parameters of achieved effectiveness of modeled or professional activity in the Arctic conditions. CONCLUSION: The paper substantiates the necessity of elaboration of personalized methods of increasing the adaptive reserves of people working and living in the Arctic zones; one of these may be modern systems based on biocontrol with feedback from physiological systems of a human. Besides, it is noted that application of the principles of the theory of the functional systems formulated by academician P. K. Anokhin, can contribute to deeper understanding of adaptation processes, changes of cognitive and professional abilities, their neurophysiological support in the Arctic conditions.

The aim of the study was to assess different combinations of time estimation ability and heart rate variability (HRV) parameters in adolescents during developing of Internet addiction (IA). The study included adolescents aged 16–17 (n = 49) living in the southern region of Russia. IA was measured using the Chen Internet Addiction Scale (CIAS). An individual minute test (IM) was performed, and HRV was recorded. There are three groups that differ in HRV, IM duration and CIAS parameters. Minimal and moderate risk of IA development was detected against a background of a tendency towards vagotonia and prolonged IM time (Group I) and balanced autonomic nervous balance and optimal IM time (Group II). A balanced autonomic nervous balance and prolonged IM time were detected in the group of persons with a moderate risk of IA and a stable IA pattern (Group III). We assume that the development of IA in adolescents may be carried out by different neural mechanisms, including optimal autonomic nervous balance, but with primary impairment of cortical brain mechanisms of time perception.

The aim of this study was to determine electroencephalogram (EEG) in a session of heart rate variability biofeedback (HRV BF) in adolescents with different Internet addiction (IA) risks. In total, 100 healthy adolescents aged 16–17 years with minimal risk of IA (Group I, 35%), pronounced risk of IA (Group II, 51%), and stable pattern of IA (Group III, 14%) using the Chen Internet Addiction Scale were examined. HRV and EEG parameters were determined at baseline (5 min), and then during the short-term HRV BF session (5 min), in order to increase the total power (TP, ms²) of the HRV spectrum. Against the background of an increase in the TP and a decrease in sympathetic activity, an increase in alpha EEG was revealed, especially in Groups I and II. The greatest increase in the power of beta₁-activity of EEG in the frontal, central, and temporal brain regionswas found in Groups I and II. In adolescents with a pronounced risk of IA, HRV BF is accompanied by a severe activation of the brain systems, while in persons with a stable type of IA, the least brain reactivity is shown, especially in the beta₁ EEG band.