EEG signatures change during unilateral Yogi nasal breathing

Airflow through the left-and-right nostrils is said to be entrained by an endogenous nasal cycle paced by both poles of the hypothalamus. Yogic practices suggest, and scientific evidence demonstrates, that right-nostril breathing is involved with relatively higher sympathetic activity (arousal states), while left-nostril breathing is associated with a relatively more parasympathetic activity (stress alleviating state). The objective of this study was to further explore this laterality by controlling nasal airflow and observing patterns of cortical activity through encephalographic (EEG) recordings. Thirty subjects participated in this crossover study. The experimental session consisted of a resting phase (baseline), then a period of unilateral nostril breathing (UNB) using the dominant nasal airway, followed by UNB using the non-dominant nasal airway. A 64-channel EEG was recorded throughout the whole session. The effects of nostril-dominance, and nostril-lateralization were assessed using the power spectral density of the neural activity. The differences in power-spectra and source localization were calculated between EEG recorded during UNB and baseline for delta, theta, alpha, beta and gamma bands. Cluster-based permutation tests showed that compared to baseline, EEG spectral power was significantly (1) decreased in all frequency bands for non-dominant nostril UNB, (2) decreased in alpha, beta and gamma bands for dominant nostril UNB, (3) decreased in all bands for left nostril UNB, and (4) decreased in all bands except delta for right nostril UNB. The beta band showed the most widely distributed changes across the scalp. our source localisation results show that breathing with the dominant nostril breathing increases EEG power in the left inferior frontal (alpha band) and left parietal lobule (beta band), whereas non-dominant nostril breathing is related to more diffuse and bilateral effects in posterior areas of the brain.These preliminary findings may stimulate further research in the area, with potential applications to tailored treatment of brain disorders associated with disruption of sympathetic and parasympathetic activity.

Similar Supine Heart Rate Variability Changes During 24-h Exposure to Normobaric vs. Hypobaric Hypoxia

Purpose: This study aimed to investigate the differences between normobaric (NH) and hypobaric hypoxia (HH) on supine heart rate variability (HRV) during a 24-h exposure. We hypothesized a greater decrease in parasympathetic-related parameters in HH than in NH.Methods: A pooling of original data from forty-one healthy lowland trained men was analyzed. They were exposed to altitude either in NH (FIO2 = 15.7 ± 2.0%; PB = 698 ± 25 mmHg) or HH (FIO2 = 20.9%; PB = 534 ± 42 mmHg) in a randomized order. Pulse oximeter oxygen saturation (SpO2), heart rate (HR), and supine HRV were measured during a 7-min rest period three times: before (in normobaric normoxia, NN), after 12 (H12), and 24 h (H24) of either NH or HH exposure. HRV parameters were analyzed for time- and frequency-domains.Results: SpO2 was lower in both hypoxic conditions than in NN and was higher in NH than HH at H24. Subjects showed similarly higher HR during both hypoxic conditions than in NN. No difference in HRV parameters was found between NH and HH at any time. The natural logarithm of root mean square of the successive differences (LnRMSSD) and the high frequency spectral power (HF), which reflect parasympathetic activity, decreased similarly in NH and HH when compared to NN.Conclusion: Despite SpO2 differences, changes in supine HRV parameters during 24-h exposure were similar between NH and HH conditions indicating a similar decrease in parasympathetic activity. Therefore, HRV can be analyzed similarly in NH and HH conditions.

ROLE OF BODY MASS AND PHYSICAL ACTIVITY IN AUTONOMIC FUNCTION MODULATION ON POST-COVID-19 CONDITION: AN OBSERVATIONAL SUBANALYSIS OF FIT-COVID STUDY

The harmful effects of coronavirus disease 2019 (COVID-19) can reach the autonomic nervous system (ANS) and endothelial function. Therefore, the detrimental multiorgan effects of COVID-19 could be induced by deregulations in ANS that may persist after the acute SARS-CoV-2 infection. Additionally, investigating the differences in ANS response in overweight/obese, and physically inactive participants who had COVID-19 compared to those who did not have the disease is necessary. The aim of the study was to analyze the autonomic function of young adults after mild-to-moderate infection with COVID-19 and to assess whether body mass index (BMI) and levels of physical activity modulates autonomic function in participants with and without COVID-19. Patients previously infected with COVID-19 and healthy controls were recruited for this cross-sectional observational study. A general anamnesis was taken and BMI and physical activity levels were assessed. The ANS was evaluated through heart rate variability. A total of 57 subjects were evaluated. Sympathetic nervous system activity in post-COVID-19 group was increased (stress index; p=0.0273). They also presented lower values of parasympathetic activity (p<0.05). Overweight/obese subjects in the post-COVID-19 group presented significantly lower parasympathetic activity and reduced global variability compared to non-obese in control group (p<0.05). Physically inactive subjects in post-COVID-19 group presented significantly higher sympathetic activity than active subjects in control group. Parasympathetic activity was significantly increased in physically active subjects in control group compared to the physically inactive post-COVID-19 group (p<0.05). COVID-19 promotes changes in the ANS of young adults, and these changes are modulated by Overweight/obesity and physical activity levels.

Study of sympathetic and parasympathetic control of haemodynamics in mid pregnancy by cardiac autonomic neuropathy analyzer

Pregnancy is associated with substantial changes in cardiovascular system. The action of autonomic nervous system is essential for circulatory adaptations in pregnancy and nourishing growing fetus. The study was conducted to assess the significance of autonomic function tests amongst women of mid pregnancy and non pregnant women. A comparative study was caried out amongst pregnant and non pregnant women in Department of Physiology. A total of 60 women (30 pregnant as study group and 30 non pregnant healthy women as control group) aged between 18- 30 years were included in study. The results indicated that there was statistically significant change in resting heart and highly statistically significant change to deep breathing in mid pregnancy reflecting higher parasympathetic activity in study group (pregnant female) as compared to control group (non pregnant female) while sympathetic activity assessed by isometric hand grip test didn’t show any statistically significant change among pregnant as compared to non pregnant. Our study showed role of parasympathetic activity in controlling haemodynamics in mid pregnancy and it may help to return the arterial pressure to non pregnant level by causing haemodilution, although when the increase in activity is excessive, hypertension may ensue.

Age-related characteristics of heart rate variability in patients with arterial hypertension: the effect of stress and habitual physical activity

Objective: identifying age-related changes in the variability of the heart rhythm (HRV) in individuals with arterial hypertension (AG) associated with psychological stress and physical activity (FA) for targeted prevention and rehabilitation. Material and methods: the survey of the main groups consisting of 37 people’s persons (26 young men and 11 girls at the age of 22,2 years) and 94 - 2nd middle age (35 men and 59 women aged 56,0 years) included: questioning, anthropometry, clinical and instrumental examination, electrocardiography, HRV monitoring. Control groups for young people (n = 72) and persons of the 2nd middle age (n = 10) were comparable with the main ones and sex. Results: the frequency of excess body and obesity, low facilities, as well as the average and high levels of psychological stress in young people with AG amounted to 51,4%, 64,1%, and 59,5%, and in middle-aged people with AG — 87,2%, 55,4% and 41,5%, respectively. With AG in persons of the 2nd middle age, in contrast to young people, HRV were characterized at a low level of psychological stress with smaller values of the parameters of SDNN, RMSSD, PNN (50) and VP, which were indicated to a smaller HRV and low parasympathetic activity and, on the contrary, higher the value of the voltage index (VI) reflecting the intensity of the control processes of the heart rhythm; with an average and high levels of stress, statistically significant differences in the above parameters were supplemented by a lower value of the triangular index, which integrally reflects the decrease in WRC. The presence of hypertension in the patients of the 2nd middle age, in contrast to young people and at a low level, and at a moderate and high levels of the FA, was accompanied by a decrease in SDNN, RMSSD, PNN (50) values, which indicated the smaller general HRV, low parasympathetic activity the vegetative nervous system; on the contrary, higher VI confirmed the participation of the central contour and the intensity of the regulation of the rhythm of the heart. Conclusion: determination of the predictors of the development of AG reflecting the general HRV, the sympathy-vagal balance and the tension of the rhythm of the heart rhythm associated with the levels of psychological stress and physical activity, as well as age, can be broadcast in an outpatient practice to designate targets of preventive and rehabilitation activities.

Targeting Parasympathetic Activity to Improve Autonomic Tone & Clinical Outcomes

In this review we will briefly summarize the evidence that autonomic imbalance, and more specifically, reduced parasympathetic activity to the heart generates and/or maintains many cardiorespiratory diseases; and discuss mechanisms and sites, from myocytes to the brain, that are potential translational targets for restoring parasympathetic activity and improving cardiorespiratory health.

Heart Rate Variability in Adults with Sickle Cell Anemia During a Multitasking Field Test

Background: The integrity of the autonomic nervous system (ANS) is essential for keeping physiological processes stable, even under stress. Since there is growing interest in heart rate variability (HRV) analysis for the noninvasive assessment of the ANS in sickle cell anemia (SCA) patients, we studied the behavior of the ANS in the presence of a stressor that simulates daily-life multitasking, the Glittre ADL test (GA-T). Objectives: To evaluate the involvement of the ANS using HRV in adults with SCA during the GA-T and to quantify the strength of the correlation of HRV with lung and muscle functions. Methods: In this cross-sectional study, 16 adults with SCA and 12 healthy controls without sickle cell disease underwent HRV assessment during the GA-T, pulmonary function tests (spirometry, diffusing capacity for carbon monoxide (DLCO), and respiratory muscle testing). Peripheral muscle function [handgrip strength (HGS) and quadriceps strength (QS)] were also measured. Results: Compared to the healthy controls, adults with SCA showed lower HRV, with worse parasympathetic modulation due to reductions in the following indices: the root-mean-square difference of successive normal iRRs (iRR) (RMSSD); the percentage of pairs of consecutive iRRs whose difference is > 50 m (pNN50); the high-frequency component of heart rate variability (HF); and the standard deviation of instantaneous beat-to-beat variability (SD1) (P < 0.001 for all). Compared to healthy controls, individuals with SCA showed greater sympathovagal imbalance (higher ratio between low-frequency and HF components) and lower complexity of the ANS (lower approximate entropy). The GA-T time was correlated with parasympathetic activity indices: RMSSD (rs = -0.650, P < 0.01); pNN50 (rs = -0.932, P < 0.0001), HF (rs = -0.579, P < 0.01), and SD1 (rs = -0.814, P < 0.0001). Correlations between parasympathetic activity indices and DLCO, HGS, and QS measures were also significant. Conclusions: Adults with SCA have low HRV, with low parasympathetic activity, sympathovagal imbalance, and abnormal ANS complexity. In addition, lower HRV is associated with longer GA-T time, greater impairment of pulmonary diffusion, and greater muscle strength dysfunction.