Changes in parameters of tachography and heart rate variability in students differing in the level of psychoemotional stress and type of temperament during an academic test week

Female students were examined to evaluate the effect of a test week on the parameters of tachography and heart rate variability depending on their initial psychoemotional stress level and type of temperament. A test week was shown to be a rather weak stressor, which virtually did not affect the psychological status of the students. However, their autonomic status clearly changed during the test week. This was caused by activation of the sympathetic autonomic system and was observed in both the students with a favorable psychoemotional state and choleric and sanguine subjects.     

Effect of Specialization in Sports on the Structural and Functional States of the Left Ventricle of the Heart in Schoolchildren of Different Biological Age

The structural and functional states of the left ventricle of the heart were studied by echocardiography in schoolchildren of three age groups. The first group included 10- to 13-year-old boys without features of sexual maturation. The second group included 13- to 15-year-old adolescents during puberty. The third group included 16- to 18-year-old adolescents with developed secondary sexual characteristics. The children were trained in sports: middle-distance running, swimming, and wrestling. It was found that the posterior wall of the ventricular myocardium in young athletes of all age groups and any specialization in sports was thicker than in untrained children of the same age. Similarly, the trained children were characterized by larger anteroposterior size of the ventricular cavity, larger cavity volume and total volume, greater myocardium mass (both absolute and calculated per kg body weight), more substantial ventricular stroke volume, lower heart rate, lesser ejection fraction, and smaller degree of shortening of the anteroposterior size of the ventricular cavity during systole as compared to untrained children of the same age. The difference between trained and untrained schoolchildren increased with increasing age, duration of the period of training in sports, and level of training in sports (athletic qualification). The training-induced changes in the structural and functional parameters of the left ventricle of the heart in middle-distance runners were larger than in schoolchildren trained in swimming and, particularly, in wrestling.     

Sleep stages after psychoemotional exposure: individuality-dependent changes

Sleep stages were studied in healthy subjects with the aid of a battery of tests involving questionnaires, psycho-tests, motor tests, polysomnography, and cardiomonitoring. An induced psychoemotional tension was shown to change the 1st sleep stage, to decrease percentage of the 2nd stage of the slow-wave sleep, to redistribute the delta-sleep, and to suppress the REM sleep mechanism. The cerebro-visceral function of increasing the heart rate and its variability in night sleep was also affected. Patterns of the sleep structure changes depended on personality characteristics of the subjects. Thereupon, individual programs should be used in studies of psychoemotional stress effects upon the sleep pattern.     

Systemic Organization of Perceptive Activity in Children with Different Levels of Mental Development

Visual evoked potentials (EPs) of the left and right hemispheres in response to relevant and irrelevant stimuli in the structures of the left and right hemispheres have been studied in healthy young schoolchildren, learning-disabled (LD) children, and mentally retarded (MR) children. In healthy children, the largest EP variations depending on the stimulus relevancy have been found in associative structures of the left hemisphere. In LD children of the same age, the amplitude and temporal characteristics of left-hemispheric EPs to target and nontarget stimuli are the same. In MR children, EPs to relevant and irrelevant stimuli do not differ from each other in either the left or the right hemisphere. EP latencies are significantly longer in MR children than in healthy children. The results of simultaneous recording of EPs in the left and right hemispheres during isolated stimulation of the right and left visual half-fields indicate that interhemispheric interaction is impaired in children with deviations in mental development. The results of the study are discussed in terms of the psychological characteristics and learning ability of children.     

Influence of the Personality Traits of Parent and Children on the Autonomic Regulation of Heart Rate in Children of Preschool Age and Adolescents

The relationship between personality traits and autonomic regulation of heart rate in children of preschool age and adolescents was studied. Significant positive correlations of the parameter of trait anxiety in children of preschool age with the index of tension (IT) of the cardiovascular system and of the value of extro/introversion of parents (mothers) with the IT of children were obtained. A relationship was revealed between school anxiety and the state of autonomic regulation of the heart rate in children of preschool age and adolescents.     

The prevalence of minor physical anomalies in mentally retarded children

The prevalence of minor physical anomalies was examined in a sample of 109 children with idiopathic mental retardation (65 boys and 44 girls). Control group consisted of 246 healthy schoolchildren (123 boys and 123 girls) aged 8 to 12 years. A comparison was made between number of found minor anomalies per child (W1) and their Waldrop weight scores (W2) in healthy and mentally retarded (MR) children. The MR children were found to have a higher number of minor anomalies per child. In their group predominated those with four or more anomalies (56.9%), whereas among healthy children only 7.7% had four anomalies or more. In contrast to the high weighted score value (W2) of five or greater in 36.7% of MR children, it was absent in all control group subjects. There were highly significant differences between the MR and healthy children in the average value of the number of minor anomalies per child (W1) and in the average weighted score (W2). The average number of minor anomalies per child (W1) in MR and well children was 3.65 and 1.7, respectively. In MR children the average weighted score (W2) was 3.82, being 1.46 in healthy children. Our results suggest that common etiological factors, which had led to a physical and mental disorder, were active early in the development of MR children. The finding of high incidence of multiple minor anomalies in MR children indicates that genetic factors may play an important role in the etiology of the underlying disorder in the child group studied.     

Reaction of the Central Nervous System to Nonverbal Psychotherapeutic Influence: An Autonomic Level of Regulation

Changes in the human functional state in response to nonverbal psychotherapeutic suggestion were studied by the electrophysiological methods of electrocardiography and galvanic skin response. It was revealed that, in 55% of subjects, the heart rate increased upon nonverbal suggestion (p < 0.01) and, in 45% of subjects, a tendency toward a decrease was observed, while the heart rate in the control group decreased (p < 0.05). The electrocardiogram T wave amplitude decreased significantly (p < 0.05) and was found to be the parameter most sensitive to psychotherapeutic influence. An increase in the galvanic skin response peaks in the period of psychotherapeutic suggestion was observed in 86.7% (p < 0.01) of subjects; on the contrary, in the control series of experiments, a tendency toward a decrease was observed. The changes revealed in the autonomic parameters of functional state permit the conclusion that the subjects perceived unconscious information during the nonverbal suggestion, and this was reflected in increased psychoemotional tension in the subjects.     

Functional characteristics of the cardiovascular system in adolescents with high normal blood pressure

Sanogenetic monitoring of schoolchildren’s health has demonstrated that, among high school students, the proportion of adolescents with elevated blood pressure (hypertension + hypernormotension) has risen from 15–20% in 8th-year students to 30–50% in 9th- to 11th-year students, while the proportion of adolescents with hypertension was 3.7% in all age groups. The level of blood pressure (BP) was compared with parameters of the autonomic control of the cardiovascular system. A high normal BP in adolescents 13–14 and 17–18 years of age was correlated with the higher proportion of low frequencies in the spectrum of heart rate variability (HRV) and with the lower sensitivity of the arterial baroreflex. At the age of 15–16 years, a high normal BP was accompanied by a reduced heart rate and a higher sensitivity of the arterial baroreflex; BP correlated also with a decrease in power of the high-frequency region of the HRV spectrum. Unlike normotensive age-matched subjects, hypernormotensive adolescents 15–16 years of age have a lower finger blood pressure and reduced relative power of the low-frequency range in the HRV spectrum during the functional test (an increase in the dead space). This may be a result of a functional inadaptability of sympathetic autonomic regulation.     

Flow dynamics and energy efficiency of flow in the left ventricle during myocardial infarction

Cardiovascular disease is a leading cause of death worldwide, where myocardial infarction (MI) is a major category. After infarction, the heart has difficulty providing sufficient energy for circulation, and thus, understanding the heart’s energy efficiency is important. We induced MI in a porcine animal model via circumflex ligation and acquired multiple-slice cine magnetic resonance (MR) images in a longitudinal manner—before infarction, and 1 week (acute) and 4 weeks (chronic) after infarction. Computational fluid dynamic simulations were performed based on MR images to obtain detailed fluid dynamics and energy dynamics of the left ventricles. Results showed that energy efficiency flow through the heart decreased at the acute time point. Since the heart was observed to experience changes in heart rate, stroke volume and chamber size over the two post-infarction time points, simulations were performed to test the effect of each of the three parameters. Increasing heart rate and stroke volume were found to significantly decrease flow energy efficiency, but the effect of chamber size was inconsistent. Strong complex interplay was observed between the three parameters, necessitating the use of non-dimensional parameterization to characterize flow energy efficiency. The ratio of Reynolds to Strouhal number, which is a form of Womersley number, was found to be the most effective non-dimensional parameter to represent energy efficiency of flow in the heart. We believe that this non-dimensional number can be computed for clinical cases via ultrasound and hypothesize that it can serve as a biomarker for clinical evaluations.     

Functional State of 11- to 12-Year-Old Schoolchildren under Conditions of Intense Academic Load Assessed by Heart Rate Variability

The functional state of sixth-grade children was estimated on the basis of heart rhythm variability data. It was found that the heart rate variability was closely correlated with learning progress during both intensive and nonintensive methods of education. The highest adaptation tension was observed in children with good learning progress during intensive methods of education.     

Heart rate variability as an autonomic index of conflict-induced behavior of individuals under emotional stress

The spectrum of and changes in motivation activity and the associated heart rate variability (HRV) were evaluated under psychoemotional stress. It was found that psychoemotional stress led to changes in the anxiety and will components of the spectrum, with certain changes in the HRV.     

The level of anxiety and state of autonomic regulation depending on the predicted examination grades in students living under unfavorable environmental conditions

The examination situation evokes psychoemotional and autonomic reactions with different degrees of intensity depending on the predicted grades in first-year students living under unfavorable conditions of the middle Ob’ River basin. All the examined students (residents of the middle Ob’ River basin) were found to have a high or super high level of trait and state anxiety. The unfavorable emotional state was accompanied by different degrees of the strengthening of parasympathetic effects on cardiac activity and the tension of regulatory systems that were at a maximum in students who expected a C grade. Irrespective of the predicted result, the highest levels of anxiety and increase in the stress of regulatory systems were observed in female students.     

Prevalence of nonspecific low back pain in schoolchildren in north-eastern Slovenia

The aim of the study was to investigate the prevalence of the nonspecific low back pain (LBP) in a population of schoolchildren in Maribor, north-eastern Slovenia. 100 children from an elementary school (age 11-15 y) and 90 children from a secondary school (age 17-18 y) were included in the study and investigated with a structured Watson questionnaire to assess low back pain prevalence, symptom characteristics, psychosocial factors, demographic, and anthropometric items. The data was statistically analysed using the SPSS software. 43% of children from elementary schools and 44% of children from secondary schools experienced back pain which lasted more than one day. No correlations between LBP and anthropometric items were found. Schoolchildren spend approximately 2 hours for learning, 2-3 hours for watching TV and approximately 2 hours for playing or working with the computer. Among important reasons for LBP, 44% of children mentioned carrying a school bag, 28% sitting on school chairs, and 18% intensive sport activity. Clinical examination of cervical, thoracic, and lumbar spine has shown that 12% of primary children and 12% of secondary children have increased cervical lordosis and 15% of primary schoolchildren have increased lumbar lordosis. In 5% of schoolchildren we found mild spinal scoliotic changes. Among our schoolchildren sedentary behaviour and low physical activity dominate. LBP may have an impact on their daily life, therefore it is important to recognise and treat it as soon as possible.     

Fractal dimension in health and heart failure.

BACKGROUND: Non-linear analysis of heart rate variability (HRV) can give additional information about autonomic control of the heart rate. This study applied the fractal dimension (FD) in a congestive heart failure (CHF) population. METHODS: FD and HRV were evaluated in a healthy population (n=21) and an end-stage heart failure population (n=21) using 1-h segments during the day and night from Holter recordings. RESULTS: CHF patients presented a loss of circadian variation in both FD and conventional time- and frequency-domain HRV indices. FD was higher in the CHF population both during the day and night. In the CHF population the correlation between FD and high-frequency power of HRV was lost. CONCLUSION: Day-night variations of heart rate fluctuations are lost in heart failure. Changes in FD reflecting physiological and pathophysiological changes were observed.     

Predicting maintenance or achievement of healthy weight in children: the impact of changes in physical fitness

Physical fitness is often inversely associated with adiposity in children cross-sectionally, but the effect of becoming fit or maintaining fitness over time on changes in weight status has not been well studied in children. We investigated the impact of changes in fitness over 1-4 years of follow-up on the maintenance or achievement of healthy weight among 2,793 schoolchildren who were first measured as 1st to 7th graders. Students were classified as "fit" or "underfit" according to age- and gender-specific norms in five fitness domains: endurance, agility, flexibility, upper body strength, and abdominal strength. Weight status was dichotomized by BMI percentile: "healthy weight" (<85th percentile) or "overweight/obese" (≥85th percentile). At baseline, of the 38.3% overweight/obese children, 81.9% (N = 875) were underfit. Underfit overweight students were more likely to achieve healthy weight if they achieved fitness (boys: odds ratio (OR) = 2.68, 95% confidence interval (CI) = 1.24-5.77; girls: OR = 4.67, 95%CI = 2.09-10.45). Initially fit overweight children (N = 194) were more likely to achieve healthy weight if they maintained fitness (boys: OR = 11.99, 95%CI = 2.18-65.89; girls: OR = 2.46, 95%CI = 1.04-5.83). Similarly, initially fit healthy-weight children (N = 717) were more likely to maintain healthy weight if they maintained fitness (boys: OR 3.70, 95%CI = 1.40-9.78; girls: OR = 4.14, 95%CI = 1.95-8.78). Overweight schoolchildren who achieve or maintain physical fitness are more likely to achieve healthy weight, and healthy-weight children who maintain fitness are more likely to maintain healthy weight. School-based policies/practices that support physical fitness may contribute to obesity reduction and maintenance of healthy weight among schoolchildren.     

Features of the power spectra of the main EEG rhythms in children with different types of attention deficit hyperactivity disorder

As a result of the examination of a group of 9- to 12-year-old children with the combined type of attention deficit hyperactivity disorder (ADHD), two variants of the clinical picture of ADHD were identified: the residual organic variant (ADHD RO) and the idiopathic variant (ADHD IP). The EEG power spectra in the main frequency ranges were studied with the eyes closed and open. The greatest intergroup differences in the power spectra were observed in the θ-band in the forntocentral and occipital derivations. In the frontocentral divisions of the cortex, the maximal values were observed in the group of ADHD RO children, whereas the highest spectral power values were observed in ADHD IP children in the occipital derivations. No statistically significant differences in the α-band spectral power between healthy subjects and ADHD schoolchildren from either group were obtained. Thus, the studies showed that these two ADHD variants have certain neurophysiological differences, which should be considered when therapeutic modalities are to be selected.     

The use of spiroarteriocardiorhythmography as a functional test for estimating the state of the cardiorespiratory system in adults and children

The heart rate, peripheral arterial blood pressure (BP), and respiration parameters were simultaneously recorded in adult subjects and young schoolchildren in two modes of testing: using a mask with airflow sensors that did not restrict air inflow but increased the pulmonary dead space and without the mask. It was demonstrated that wearing the mask was a functional test for the state of the cardiorespiratory system in both age groups; however, the responses of the children’s and adults’ bodies differed from each other, probably, because of the functional immaturity of the sympathetic component of the autonomic control. In adults, the parameters of the cardiovascular system did not change, except that the heart rate variability spectrum was redistributed toward an enhancement of the high-frequency component. In children, testing with the mask on decreased the systolic BP; increased the heart rate; and, as evidenced by the spectral characteristics of BP variability, activated the sympathetic nervous system.     

Cardiac Rhythm Regulation in Children during the Initial Period of School Education under Conditions of the North

Cardiac rhythm parameters recorded in healthy children during the initial weeks of schoolwork immediately after the transition from kindergarten to the first grade of the elementary school or from the elementary school to the fifth grade of the middle school showed that their regulatory systems were stressed to different degrees, reflecting different costs of adaptation to environmental conditions. The most pronounced changes in these parameters were observed in the first graders: because of more significant stress (sometimes, overstress) of their regulatory mechanisms, in 70% of these children complete adaptation to new living conditions was associated with greater physiological costs. In the fifth graders, a similar situation was observed only in 25% of the children examined. The less pronounced physiological changes observed in 30% of the first graders and in 75% of the fifth graders can be related to the more mature state of their cardiac regulatory mechanisms, as well as to their greater adaptability to environmental conditions during the period examined.     

Influence of moderate physical exercise on the cardiac rhythm parameters of elementary and junior high school children

To reveal the specific features of the influence of moderate exercise (running) on the autonomic regulation of the cardiac rhythm, changes in the heart rate variability (HRV) parameters have been analyzed during three months in 292 children aged 9–14, as dependent on the sex and the baseline autonomic tone estimated by means of cluster analysis. It has been shown that, in schoolchildren engaged in running for health, HRV changes give evidence for the optimization of the mechanisms of autonomic regulation. The HRV parameters in the girls were more resistant to muscular activity compared to boys. The data obtained indicate that running for health requires a differential approach to dosing of the exercise, taking into account the sex and the baseline autonomic tone.     

Circadian Time Structure of Cardiovascular Characteristics in Human Pregnancy

Conventional time-unspecified single measurements of blood pressure and heart rate may be misleading because they may be influenced, among other factors, by the patient's emotional state, position, diet, and external stimuli. All of these effects depend on the stages of a (mathematical) spectrum of rhythms and trends with age. The evaluation of predictable variability in blood pressure and heart rate by (a) the use of fully ambulatory devices, and (b) chronobiologic data processing, assesses early cardiovascular disease risk, e.g., in pregnancy. We have used this approach to quantify changes in 24-h synchronized (circadian) characteristics of cardiovascular variables in two consecutive pregnancies of a clinically healthy woman. Blood pressure and heart rate were automatically monitored, with few interruptions, at I-h intervals, each time for at least 48 consecutive h, and for a total of 76 days of monitoring in each pregnancy. Circadian parameters of those circulatory variables were computed for each single day of measurement by the least-squares fit of a 24-h cosine curve. Regression analysis of parameters thus obtained revealed patterns of variation of circadian-rhythm-adjusted means and amplitudes with gestational age. In both pregnancies, the predictable variability of the circadian-rhythm-adjusted mean of blood pressure can be approximated by a second-order polynomial model on gestational age: a steady linear decrease in systolic, diastolic, and mean arterial blood pressure up to the 22nd week of pregnancy is followed by an increase in blood pressure up to the day of delivery. This longitudinal study confirms and extends to ambulatory everyday life conditions the predictable pregnancy-associated variability in blood pressure and heart rate and also allows the establishment of prediction and confidence limits for cardiovascular parameters in a healthy pregnancy.