Hypertension (HTN) and prehypertension (pre-HTN) have been identified as independent risk factors for adverse cardiovascular events. Recently, increased psychosocial stress and work stress have contributed to the increased prevalence of HTN and pre-HTN, in addition to the contribution of obesity, diabetes, poor food habits and physical inactivity. Irrespective of the etiology, sympathetic overactivity has been recognized as the main pathophysiologic mechanism in the genesis of HTN and pre-HTN. Sympathovagal imbalance owing to sympathetic overactivity and vagal withdrawal is reported to be the basis of many clinical disorders. However, the role played by vagal withdrawal has been under-reported. In this review, we have analyzed the pathophysiologic involvement of sympathovagal imbalance in the development of HTN and pre-HTN, and the link of sympathovagal imbalance to cardiovascular dysfunctions. We have emphasized that adaptation to a healthier lifestyle will help improve sympathovagal homeostasis and prevent the occurrence of HTN and pre-HTN.

Background:Specific nostril breathing is known to influence autonomic functions.Aim:The study was to assess the effects of right nostril breathing (RNB) and left nostril breathing (LNB) on heart rate variability (HRV) and cardiovascular functions.Material and Methods:Eighty-five student volunteers were divided into three groups: RNB group (n = 30), LNB group (n = 30), and control group (n = 25). RNB and LNB group subjects practiced right and left nostril breathing, respectively, every day 1 h for 6 weeks. The control group did not practice nostril breathing. Cardiovascular parameters and spectral indices of HRV were recorded before and after 6-week practice of nostril breathing. In RNB and LNB groups, prediction of rate-pressure product (RPP) by low-frequency to high-frequency ratio (LF-HF) of HRV was assessed by bivariate logistic regression.Results:HRV indices representing sympathetic activity were increased in the RNB group and indices representing parasympathetic activity were increased in LNB group following 6-week nostril breathing. Prediction of LF-HF to RPP, the marker of cardiovascular risks, was more significant (OR 2.65, P = 0.005) in the LNB group compared to the RNB group (OR 1.452, P = 0.016).Conclusions:Short-term practice of LNB improves vagal tone, increases HRV, and promotes cardiovascular health of medical students. Practice of RNB increases sympathetic tone and could jeopardize cardiovascular health.

AIMSThe purpose of this study was to evaluate whether yoga training in addition to standard medical therapy can improve cardiac function and reduce N terminal pro B-type natriuretic peptide (NT pro BNP) in heart failure (HF).METHODS130 patients were recruited and randomized into two groups: Control Group (CG) (n = 65), Yoga Group (YG). In YG, 44 patients and in CG, 48 patients completed the study. Cardiac function using left ventricular ejection fraction (LVEF), myocardial performance index (Tei index), and NT pro BNP, a biomarker of HF, was assessed at baseline and after 12 weeks.RESULTImprovement in LVEF, Tei index, and NT pro BNP were statistically significant in both the groups. Furthermore, when the changes in before and after 12 weeks were in percentage, LVEF increased 36.88% in the YG and 16.9% in the CG, Tei index was reduced 27.87% in the YG and 2.79% in the CG, NT pro BNP was reduced 63.75% in the YG and 10.77% in the CG. The between group comparisons from pre to post 12 weeks were significant for YG improvements (LVEF, P < 0.01, Tei index, P < 0.01, NT pro BNP, P < 0.01).CONCLUSIONThese results indicate that the addition of yoga therapy to standard medical therapy for HF patients has a markedly better effect on cardiac function and reduced myocardial stress measured using NT pro BNP in patients with stable HF.

We conclude that PCOS patients have altered autonomic modulation in the form of increased sympathetic and decreased parasympathetic reactivity and HRV. The sympathovagal imbalance exposes them to cardiovascular morbidities.

Though the incidence of hypertension has increased considerably in recent years, the pathophysiologic mechanism that causes progression from stage of prehypertension to hypertension has not been fully elucidated. Therefore, the present study was conducted to assess the sympathovagal imbalance in prehypertensives and hypertensives by spectral analysis of heart rate variability (HRV) to understand the nature of change in autonomic balance in this common dysfunction of mankind. Body mass index (BMI), basal heart rate (BHR), blood pressure (BP), and spectral indices of HRV such as total power (TP), normalized low frequency power (LFnu), normalized high frequency power (HFnu), ratio of low frequency power to high frequency power (LF-HF ratio), mean heart rate (mean RR), square root of the mean squared differences of successive normal to normal intervals (RMSSD), the number of interval differences of successive NN intervals greater than 50 ms (NN50), and the proportion derived by dividing NN50 by the total number of NN intervals (pNN50) were assessed in three groups of subjects: normotensives (n = 32), prehypertensives (n = 28), and hypertensives (n = 31). Sympathovagal balance was analyzed and correlated with BMI, BHR, and BP in all the groups. It was observed that autonomic imbalance in prehypertensives was due to proportionate increased sympathetic activity and vagal inhibition, whereas in hypertensives, vagal withdrawal was more prominent than sympathetic overactivity. The LF-HF ratio, the sensitive indicator of sympathovagal balance, was significantly correlated with BMI, BHR, and BP. It was concluded that vagal inhibition plays an important role in the critical alteration of sympathovagal balance in the development of clinical hypertension in prehypertensive subjects.