Acute effects on cardiovascular oscillations during controlled slow yogic breathing.

BACKGROUND & OBJECTIVES: Breathing exercises are believed to modulate the cardiovascular oscillations in the body. To assess the validity of the assumption and understand the underlying mechanism, the key autonomic regulatory parameters such as heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were recorded during controlled slow yogic breathing. Alternate nostril breathing (ANB) was selected as the yogic manoeuvre. METHODS: Twelve healthy volunteers (age 30±3.8 yr) participated in the study. ANB was performed at a breathing frequency of 5 breaths per minute (bpm). In each participant, the electrocardiogram, respiratory movements, beat-to-beat BP and end-tidal carbon dioxide were recorded for five minutes each: before, during and after ANB. The records were analyzed for HRV, BPV and BRS. RESULTS: During ANB, HRV analysis showed significant increase in the standard deviation of all NN intervals, low-frequency (LF) component, LF/HF (low frequency/high frequency) ratio and significant decrease in the HF component. BPV analysis showed a significant increase in total power in systolic BPV (SBPV), diastolic BPV (DBPV) and mean BPV. BRS analysis showed a significant increase in the total number of sequences in SBPV and DBPV and significant augmentation of α-LF and reduction in α-HF. The power spectrum showed a dominant peak in HRV at 0.08 Hz (LF component) similar to the respiratory frequency. The acute short-term change in circulatory control system declined immediately after the cessation of slow yogic breathing (ANB) and remained elevated in post-ANB stage as compared to the pre-ANB. INTERPRETATION & CONCLUSIONS: Significant increase in cardiovascular oscillations and baroreflex recruitments during-ANB suggested a dynamic interaction between respiratory and cardiovascular system. Enhanced phasic relationship with some delay indicated the complexity of the system. It indicated that respiratory and cardiovascular oscillations were coupled through multiple regulatory mechanisms, such as mechanical coupling, baroreflex and central cardiovascular control.

Attentional Differences Between Males and Females for Emojis During the Emotional Stroop Task.

Introduction Cognitive load can be intensified by emotional components such as emotive words or facial expressions. Sex differences influence both emotional and cognitive functions for emotional facial expressions. Emojis, in contrast to human faces, serve as digital cues conveying emotional nuances in communication. The present study aimed to compare attentional differences prompted by emojis. Methods This study aimed to compare attentional differences in males and females elicited by emojis in 100 healthy adults (50 males and 50 females) within the age group of 18 to 40 years (mean ± SD: 27.87 ± 5.37 years) while performing the emotional Stroop task (EST). The EST comprised emojis depicting four emotions (happy, fear, sad, and angry) and emotionally charged words conveying similar emotions. An independent sample t-test was used to compare the reaction times among males and females. Results Results showed males had significantly longer reaction times than females across all task conditions. Both genders exhibited significant differences in reaction times across task conditions, except inhibition. Overall, reaction times increased notably from neutral to incongruent conditions for both genders. This suggests that response times increased significantly from neutral to incongruent conditions. Conclusion Emojis introduced in the EST revealed gender-related differences in attentional processing. This study showed the greater proficiency of females in emotional processing during EST compared to males. These findings contribute to our understanding of how gender is associated with cognitive responses to emotional stimuli in digital communication contexts.

Exploring Ultra-short Heart Rate Variability Metrics in Patients with Diabetes Mellitus: A Reliability Analysis.

Objectives: Ultra-short heart rate variability (HRV) metrics represent autonomic tone parameters derived using small epochs of interbeat interval data. These measures have risen in popularity with the advent of wearable devices that can capture interbeat interval data using electrocardiography (ECG) or photoplethysmography. Autonomic neuropathy in diabetes mellitus (DM) is well established, wherein 5-min HRV is conventionally used. Ultra-short measures have the potential to serve as markers of reduced autonomic tone in this patient population. Methods: Data of patients with Type I and Type II DM who had presented to our laboratory for autonomic neuropathy assessment were chosen for analysis. One-minute and 2-min epochs were chosen from 5 min of ECG data using standard software. Time domain, frequency domain, and nonlinear measures were computed from 1 to 2 min epochs, and reliability was compared with measures derived from 5-min HRV using intraclass correlation coefficients (ICCs). Results: Data of 131 subjects (79 males, 52 females; mean age = 53.3 ± 12.16 years) were analyzed. All ultra-short HRV measures derived from 1 min to 2 min data showed good to excellent reliability (median ICC values ranging from 0.83 to 0.94) when compared with 5-min metrics. The notable exception was very low frequency (VLF) power, which showed poor reliability (median ICC = 0.43). Conclusions: Ultra-short HRV metrics derived from 1 to 2 min epochs of ECG data can be reliably used as predictors of autonomic tone in patients with DM. VLF power is poorly reproducible in these small epochs, probably due to variability in respiratory rates. Our findings have implications for ultra-short HRV estimation using short epochs of ECG data.

Long Sudarshan Kriya Yoga enhances cardiovascular and respiratory synchronization: An observational study.

BACKGROUND: Sudarshan Kriya Yoga (SKY - a rhythmic cyclic breathing) is known to produce several physiological changes in human body. Earlier it has been reported that SKY improves cardiovascular modulations, namely increase in heart rate variability. OBJECTIVE: To observe the synchronization in oscillatory modulations in cardiac autonomic tone and ventilatory exchange during Long Sudarshan Kriya Yoga (LSKY). LSKY is a sequential combination of pranayama in ujjayi breath, bhastrika, and cyclic rhythmic breathing followed by yog-nidra. METHODS: Regular LSKY practitioners from the Art of Living community with more than two years of experience participated in the study (n = 22; age 40.09 ± 12.68). The Electrocardiogram (ECG), respiration, oxygen saturation, and concentrations of oxygen and carbon-di-oxide from exhaled air were recorded before and during LSKY. The time domain parameters of heart rate variability (HRV) were calculated from ECG. All parameters were compared and correlated at each stage of LSKY. RESULTS: Highly significant reciprocal correlation was found between HRV parameters and respiration rate during LSKY. Both O2 consumption and CO2 production increased significantly during three stages of pranayama and decreased towards the end of cyclic breathing. We also saw increased SPO2 simultaneously. CONCLUSION: The autonomic parameters exhibited reciprocal response to respiratory rate and correlated well to the ventilatory parameters. Further during LSKY we observed enhanced synchronization. In conclusion the LSKY has a potential to influence cardiorespiratory parameters for improving the performance of both systems. LSKY - enhances oscillations in HRV that resets the autonomic system, indicative of better cardiac health and prepares body for better metabolic response. Such changes are capable of inducing resilience along with physiological, psychological relaxation and emotional well-being.

Autonomic Correlates of Letter Cancelation Task: What the Attention Load May Evoke?

OBJECTIVE: Attention can be assessed through Letter cancelation tasks (LCT) that employ visuospatial selection and appropriate motor responses. We examined the performance in the LCT with increasing attention load, and determined the related autonomic changes. METHODS: Autonomic parameters were estimated in healthy males at baseline and during three different cognitive load conditions using the LCT. RESULTS: Results revealed a statistically significant difference (n = 30) in the percent accuracy (χ2(2) = 15.2, p < .001) and percent omission (χ2(2) = 13.3, p = 0.001) with the increasing challenge in the LCT. The vagally-mediated measures of heart rate variability were significantly decreased with the commencement of the task revealing a parasympathetic withdrawal. The respiratory sinus arrythmia was decreased, and the photoplethysmography amplitude was significantly reduced (χ2(3) = 14.2, p = 0.003) as the attention demand increased. CONCLUSION: The performance declined with the increasing attention load. LCT evokes autonomic perturbations though overall autonomic variability does not change remarkably.

Effects of Sudarshan KriyaYoga and Advanced Meditation Program on Genetic Expression of Pro-inflammatory and Antioxidants Genes.

Background Stress leads to immune system dysregulation and dyshomeostasis at the gene level. Mind-body practices are known to influence genomic expression, leading to better health and quality of life. Objective To assess the effect of Advanced Meditation Program (AMP) on the mRNA expression of pro-inflammatory and antioxidative genes among those already practicing Sudarshan Kriya Yoga (SKY). Methods A total of 97 healthy volunteers participated in the study, distributed into two groups. The Group I SKY practitioners attended a four-day AMP (50 participants with an average age of 38.8 ± 11.9 consisting of 37 females and 13 males); they are first-time participants of the AMP. Group II SKY practitioners, on the other hand, consisted of 47 participants with an average age of 36.4 ± 9.3 with 43 females and four males. At day 0, day 5, and day 90, the mRNA expression of pro-inflammatory genes, namely interleukin (IL) 1ß, IL6, and the tumor necrosis factor (TNF), and the expression of antioxidative genes, namely superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) was observed. The data were analysed in two phases due to the emergence of coronavirus disease 2019 (COVID-19): (i) pre-COVID-19 and (ii) during COVID-19. Results In the pre-COVID-19 data set, IL1ß, IL6, and TNF were found to have decreased in both groups. There is a significant increase in the expression of SOD and catalase in Group I and a decrease in Group II by day 90. During COVID-19, pro-inflammatory genes increased in Group I and had no significant change in Group II. All three antioxidant genes had decreased expression by day 90 in Group I; SOD decreased in Group II. Interpretation and conclusions Reduced expression of pro-inflammatory genes and increase in the expression of antioxidative genes during the pre-COVID-19 time suggest that the practice of SKY and added AMP may enhance antioxidative defense and may reduce the chance of getting diseases related to inflammation in the body.

Forensic tool for sex prediction- hand dimensions.

Background: Determination of sex from mutilated body fragments can perform vital role for identification of departed soul. Forensic authority pacts with human identification from the hand measurements which is of prodigious assessment during tragedies, terror attacks and in criminality. Objective: Present study explored the analytical role of the anthropometric measurements of hand dimensions, find demarking points for male and female, check percentage exactitude of sex determination in Western Indian population. Methods: The study was piloted on a sample of 504 individuals. All the measurements were taken by standard procedure. Discriminant analysis and demarking points were created for all hand measurements. Results: Males have a significantly higher values of all measurements than females. The left-hand length measurement unveiled a noteworthy sexual dimorphism index (110.80). The higher value of the demarking point labelled as males. The best sexually dimorphic hand dimensions showed the utmost precision left hand length (95% in the male), followed by right hand length (76.1%). Conclusion: All hand measurements like length, breadth and index are displaying sexual dimorphism, hence they can be used for determination of sex when isolated hand is found.

Critical Self-Appraisal Towards the Better Use of a Webinar Series as an Online Tool for Postgraduate Teaching.

INTRODUCTION: The current coronavirus disease 2019 (COVID-19) pandemic adversely affected the conventional teaching mode, resulting in an exponential rise in online modalities such as webinars. Simultaneously, the lockdown provided substantial time to pursue potential academic content on the web. It is known that newly admitted postgraduate students of Physiology require a structured program that can guide them to conduct research for the completion of the course. METHODS: Gauging the opportunity, a webinar series was conducted on basic research methodology and thesis writing in Physiology. The series comprised hourly lectures delivered between 4:00 and 5:00 pm for seven consecutive days. Suggestions for future topics for webinars were sought through open-ended questions. Additionally, feedback for increment in students' knowledge at the end of the webinar was also inquired on a Likert scale. Open-ended answers were pooled into fields, and Likert scale scores were evaluated. RESULTS: There were 364 (35.8%) postgraduate students who registered for the webinar. The remaining were faculty (51.6%), research scholars (8.8%), and senior residents (3.8%). Among the postgraduate students who submitted the feedback, a majority (98.4%) of them agreed that their knowledge was enhanced at the end of the series. Most of the postgraduate students (31%) chose Biostatistics for future webinars. CONCLUSION: Webinars are a useful tool for postgraduate teaching. They should be constructed with engaging infrastructure and relevant examples. The availability of recorded content on the online forum is beneficial for asynchronous learners. Having an idea about students' choice for essential topics helps in the advanced planning of a demanding webinar.

Respiratory rate extraction from single-lead ECG using homomorphic filtering.

In this paper a new technique for the extraction of respiratory signal from the single-lead ECG using generalized homomorphic filtering is presented. It is proposed to perform band pass filtering on the cepstrum of the ECG signal to extract the respiratory signal. For this study, transforms used in generalized homomorphic filtering are the discrete Fourier transform (DFT) and the discrete cosine transform (DCT). The performance of the ECG-derived respiration (EDR) signal obtained using the proposed method is compared with the reference respiratory signal in terms of the correlation, magnitude squared coherence coefficients and breath rate accuracy. It is observed from the comparisons that the EDR technique based on generalized homomorphic filtering using DFT performs better than the homomorphic filtering using DCT. The proposed EDR technique is also compared with the two well-known EDR techniques: principal component analysis and R peak amplitude algorithm. It is seen from the results that the proposed EDR technique (RDFT) performs significantly better than the R peak amplitude algorithm, but significant improvements are not observed when compared with the PCA based EDR technique.