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Introduction: The QTc interval is affected by heart rate, autonomic nervous system and diseases like diabetes. However, the affect of exercise which alters autonomic nervous system activity, on QTc is not clear. On the other hand, the incidence of sudden cardiac death increases many fold post exercise. These events may be better explained by studying the effect of exercise on QTc. Aim: This study was designed with an aim to record the QTc interval changes in response to isometric exercise in a group of normal individuals with or without parental history of diabetes mellitus. Also the QTc duration was correlated with the LF-HF ratio. Materials and Methods: Twenty nine, healthy medical students were subjected to isometric hand grip test for 5min. ECG was recorded pre-exercise and at various time intervals post-exercise. Statistical Analysis: All data are expressed in mean ± SD. Intra group comparison was done using paired t-test and unpaired t-test was used for comparison among group I and group II subjects, and among males and females. Result: The difference in the pre and post exercise QTc values both within and between groups was statistically significant with group I subjects recording lower values. The post exercise LF: HF values were significantly increased when compared to pre exercise values in both the groups. There was no correlation between LF: HF and QTc. Conclusion: A longer than normal QTc interval predisposes to arrhythmia. Exercise brings about detectable changes in the QTc interval after a period of isometric exercise in normal individuals which in high risk individuals may predispose to sudden cardiac death. In addition women may be more susceptible to post-exercise arrhythmia owing to a longer QTc even at rest. [ABSTRACT FROM AUTHOR]

Context: Premenstrual stress affects 75% of women of childbearing age and yoga has been found to be beneficial in many psycho-somatic disorders. Aims: To investigate the effect of integrated yoga on autonomic parameters and psychological well-being during both pre and post phases of menstrual cycle in healthy young female subjects. Settings and Design: Present study is a randomized control trial and was conducted in the Department of Physiology, Lady Hardinge Medical College, New Delhi, India. Material and Methods: Fifty apparently healthy females in the age group of 18-20 years were randomized into two groups: Group I (n=25) consisted of subjects who practiced yoga 35-40 minutes per day, six times per week for the duration of three menstrual cycles. Training was given by qualified yoga instructor. Group II (n=25) subjects acted as controls. Following parameters were recorded at the beginning and after completion of three menstrual cycles in all the subjects: Height, weight (BW), Resting Heart Rate (HR), Resting Systolic (SBP) and Diastolic Blood Pressure (DBP), parasympathetic reactivity tests including Expiration-Inspiration Ratio (E: I ratio) and 30:15 ratio, sympathetic reactivity tests including BP changes due to Isometric Hand Grip (IHG) exercise, and Cold Pressor Test (CPT). Assessment of psychological status was done by administering DIPAS (Defense Institute of Physiology and Allied Sciences) inventories of Anger self report scale, Trait Anxiety, Sense of well-being and Depression scale. Statistical Analysis: Intra-group comparison of physiological parameters was done by using paired 't' test, whereas intragroup comparison of non-parameteric data such as scores of anxiety, depression, anger and sense of well-being was done by Wilcoxon signed-rank test. Inter-group comparison of parameters was done by Students 't' test for parametric tests and Mann-Whitney 'U' test for non-parameteric tests. Results: There was significantly higher BW, resting SBP, DBP, sympathetic activity and blunting of parasympathetic reactivity and also, significantly higher scores of anger, depression, anxiety and decreased score of well-being in premenstrual phase as compared to postmenstrual phase in both the groups in initial cycle. There was significantly higher percentage decrease in BW, HR, SBP & DBP in yoga group as compared to control group in both the phases from initial to second and onwards between second and third menstrual cycle. Also, decrease in anger, depression and anxiety and increase in well-being score was significant in yoga group as compared to control group from initial to second and third cycle in premenstrual phase while the change was significant only in depression score in postmenstrual phase. Conclusion: Our study shows that there was significant alteration of autonomic functions and psychological status in premenstrual phase when compared with postmenstrual phase in young healthy females. Also, regular practice of yoga has beneficial effects on both phases of menstrual cycle by bringing parasympathodominance and psychological well-being probably by balancing neuro-endocrinal axis. [ABSTRACT FROM AUTHOR]