The purpose of the present study was to determine whether there is a menstrual cycle effect on heart rate, blood pressure and heart rate variability. 10 healthy regularly cycling females (age 19-23 years) were studied during the follicular phase and luteal phase over two month. We found significant changes in heart rate, AMo and stress index during the menstrual cycle with a minimum in the follicular phase and maximum in the luteal phase. The HF and LF components decreased more during the luteal phase than during the follicular phase (p < 0.05), whereas a tendency for increase LF/HF was observed in the luteal phase. In the follicular phase SDNN, pNN50, Mo, MxDMn were significantly higher than in the luteal phase. Furthermore, the VIK was higher in the luteal phase compared to the follicular phase (p = 0.003). Blood pressure did not show any significant change during both these phases of the menstrual cycle. These findings indicate that sympathetic nervous activity in the luteal phase is greater than in the follicular phase, whereas parasympathetic nervous activity is predominant in the follicular phase. A difference of the balance of ovarian hormones may be responsible for these changes of autonomic functions during the menstrual cycle.
P-789 Introduction: The association between birth weight, birth length and height has been well documented in literature. There, has been increasing interest in influence of race and ethnic factor on the association. We examined possible association between birth weight, birth length and height in Chuvash children at the age of 2–3 and 4–6. Methods: The longitudinal study was covered 523 people (262 girls and 261 boys) at 2 to 3 years of age living in Novocheboksarsk city of the Chuvash Republic. All these children were born at time. Data on height, birth weight and birth length were obtain from,, the history of development of a child”(HDC). HDC contains birth weight, birth length and height of a child of each age period, which were measured by nurses. Data on birth weight and birth length, obtained from HDC, were compared with height at the age of 2–3 and 4–6. We used correlation and regression analysis for estimate the association. Results: The results of correlation analysis witness of statistic strong positive association between birth weight, birth length and height in children at the age of 2–3 years and 4–6 years. Boys’ birth length (r = 0.18, p<0.05) and birth weight (r = 0.16, p<0.05) is associated with height at age 2–3 years, unlike girls, of which this association was not found (accordingly r = 0.1, p>0.05; r = 0.11, p>0.05). The similar actions permitted find statistic strong positive association between examined variables at age 4–6 years. At boys’ degree of countenance association between birth weight, birth length and height increased at age 4–6 years (accordingly r = 0.21, p<0.05; r = 0.24, p<0.05), and find association between birth weight in girls (r = 0.16, p<0.05). For deeper estimate of the relation between birth weight, birth length and height at the age of 2–3 and 4–6 we used regression analysis, in which the covariate was age. We found a clear association between birth weight, birth length and height at the age of 2–3 years and 4–6 years; the association was most expressed for birth length in boys at the age of 2–6 and for birth weight in girls at age 4–6 years. Discussion and conclusion: The results of our research of the association between birth weight and height, birth length and height are in agreement with conclusions other authors and prove about importance of birth weight and birth length as cofactors in epidemiological research in Chuvashia.
Although it is known that sound exposure evokes changes in autonomic activity, the effects of noise and music on the nonlinear behavior of heart rate fluctuations remain poorly understood and controversial. This study aims to assess the influence of sound subjective emotional valence and arousal on the nonlinear characteristics of the autonomic nervous system during passive listening.In this study, 42 subjects listened to four sounds: (1) white noise, (2) road traffic noise, (3) excitatory music, and (4) a lullaby. The experiment consisted of two consecutive sessions: 5 minutes of rest, followed by 5 minutes of listening. RR intervals were recorded during both sessions. The following linear and nonlinear heart rate variability (HRV) indices were computed: Standard deviation of NN (SDNN), The root mean square of successive differences between normal heartbeats (RMSSD), F, high frequency (HF), approximate entropy (ApEn) and sample entropy (SampEn), correlation dimension (D2), Poincaré plot indices (SD1, SD2), fractal scaling exponents (alpha1, alpha2), and recurrence plot indices (mean line length [Lmean], maximum line length [Lmax], determinism [DET], laminarity [LAM], maximal vertical length [Vmax], trapping time [TT], Shannon entropy of line length distribution [ShanEn]).Excitatory music was associated with a significant decrease in SDNN (from 47.3 ± 3.59 to 38.31 ± 3.16, P < 0.01), RMSSD (from 51.07 ± 4.75 to 42.53 ± 3.9, P < 0.05), HF (from 1516.26 ± 245.74 to 884.07 ± 183.44, P < 0.001), and low frequency (LF; from 973.33 ± 176.09 to 760.28 ± 150.35, P < 0.05). Excitatory music exposure induced significant increases in DET (P < 0.01), SD1 (P < 0.05), and SD2 (P < 0.05), but changes in detrended fluctuation analysis (DFA), SampEn, and D2 were nonsignificant. Traffic noise, white noise, and the lullaby did not cause significant changes in the measures of HRV.Presentation of excitatory music that evokes strong negative emotions elicits a prominent decrease in respiratory sinus arrhythmia. Poincaré plot and recurrence plot measures possess high sensitivity to excitatory music. Contrary to previous studies, we did not find the effects of relaxing music on HRV.
В межсессионной период и непосредственно перед экзаменом изучались изменения параметров вариабельности сердечного ритма, артериального давления и ситуационной тревожности, вызванные экзаменационным стрессом, и зависимость таких изменений от вероятного прогнозирования и реальной экзаменционной оценки. Перед экзаменом у большинства студенток отмечалось увеличение ситуационной тревоженности, диастолического артериального давления и частоты сокращений; последнее связано с повышением отношения LF/HF. Установлено, что характер изменения состояния сердечно-сосудистой системы у студенток в условиях психоэмоционального стресса значительно варьирует в зависимости от уровня их подготовленности и субъективного прогноза успешности сдачи экзамена. Выявлена значимость характера регуляции сердечного ритма в межсессионный период для протекания экзаменационного стресса.
Although there have been many studies on health effects of noise, studies on the relationship between white noise and cardiorespiratory function are limited. In the present study, we examined whether white noise affects induced changes in functioning of cardiorespiratory system in thirty-two university female students. The white noise was binaurally presented through headphones. The test intensity of white noise was 60 dBA. Beat-to-beat R-R intervals and respiratory signals were continuously recorded prior to and during the exposure to noise. Comparative analysis of the significance of heart rate showed that noise exposure causes an increase in heart rate (Z = 2,04; p white noise results significant decrease of high-frequency power (HF) (Z=2,12; рwhite noise was significantly greater than the rest condition (Z=2,02; рrespiratory rate were found for white noise (Z=2,69; рwhite noise can be detected using analysis of heart rate variability.
This data article aimed to assess whether there is a relationship between baseline heart rate variability (HRV) and mental stress-induced autonomic reactivity. Out of 1206 healthy subjects, 162 students were randomly selected to participate in this study. Participants were presented with a mental arithmetic task of 10 min duration. The task required serial subtraction of 7 from a randomly selected 3-digit number. During performance of this task as well as at baseline, ECG was recorded to acquire heart rate and HRV (high frequency, low frequency, the standard deviation of NN) data. Participants were divided into quartiles according to baseline HRV. Mental stress responses were compared across groups. We observed significant differences for autonomic reactivity scores between groups with high versus low baseline HRV. Linear regression results were consistent with the regression to the mean model and mental stress reaction (defined as mental stress value minus baseline value) negatively correlated with baseline values. Baseline-adjusted analyses did not demonstrate significant intergroup differences for changes in heart rate and HRV from rest to mental stress. These data suggest regression to the mean is a major source of variability of stress-related changes in heart rate variability.
