Nirmala S Anand

Abstract

There are unanswered questions with respect to participation of females in competitive sports whether the fluctuating sex steroid levels of menstrual cycle affect the muscle contractility, endurance as well as the metaboreflex generated out of it. Aim: To study the impact of different phases of menstrual cycle on select muscle properties like MVC, MET, time to fatigue as well as HR and BP responses to the static isometric exercise metaboreflex. Materials and Methods: Thirty eumenorrhic females were enrolled during different phases of menstrual cycle. The subjects were asked to maintain the grip on the Jamar hand grip dynamometer at 30% MVC, the endurance time and time to fatigue were calculated and cardiovascular responses arising out of it like Heart rate, BP were recorded. Statistical Analysis: Data was analyzed statistically using student’s paired t-test. Results: The luteal phase showed higher values for all the baseline characteristics like HR, SBP and DBP. The (210±12.51) sec endurance time in the follicular phase was greater than (196±19.15) sec in the luteal phase, the MVC value (162±16.45) Newton was significant in the follicular phase as compared to luteal phase value of (158±20.34) Newton, The HR was (90±26.45) bpm in the follicular and (98.2±32.34) bpm in the luteal phase using isometric HGD. Conclusion: The luteal phase of menstrual cycle emphasized that the muscle was easily fatigued vis-a –vis the follicular phase where the muscle exemplified a greater contractile strength. The pressor response to the ergonomically generated metaboreflex for a bout of static isometric exercise was higher during the luteal phase. Keywords: Follicular, HGD, Isometric, MVC.

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Introduction: The gonadal hormones accompanying the menstrual cycle in a female affect the ventricular repolarization regionally in the cardiac muscle as well as affects its recovery time both of which are QTc AND QTd measured conventionally using a non-invasive ECG. A prolonged QTc and QTd are predictors of cardiac morbidity and mortality. Aim: The aim of the present study was to examine whether the cardiac ventricular repolarization is altered during different phases of menstrual cycle by the endogenous gonadal hormones. Materials and Methods: Thirty eumenorrhic females were examined using 12 lead ECG during the follicular and luteal phases of menstrual cycle. Statistical Analysis: Data was analysed statistically using student’s paired t-test. Results: It was observed that the heart rate in follicular phase was (78.8 ±7.48) while in luteal (84 ± 8.17), R-R interval in follicular was (82±5.89) while in luteal phase was (77±3.69) QT interval in follicular was (0.39±0.09) while in luteal phase was (0.33±0.08), QTc in follicular was (0.43±0.03) while in luteal phase was (0.39±0.03), QTd in follicular was (67 ± 2.30) while in luteal phase was (58±4.08). Conclusion: We hence elucidate interactions between the sex steroids and cardiac conduction dynamics which is characterized by a prolonged QTc and QTd during the follicular phase. Keywords: Endogenous, Gonadal, Menstrual cycle, Repolarization

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Introduction: The endogenous gonadal hormones accompanying the menstrual cycle affect the cardiovascular responses to a bout of static isometric exercise. The uncertainty over the consensus as to which phase of menstrual cycle poses greater cardiovascular stress on the female was a question often unanswered. Aim: The aim of the present study was to assess the influence different phases of menstrual cycle on cardiovascular responses like heart rate, blood pressure, rate pressure product to static isometric handgrip exercise. Materials and Methods: Thirty eumenorrhic females were examined after using a hand grip dynamometer during the follicular and luteal phases of menstrual cycle. Statistical Analysis: Data was analysed statistically using student’s paired t-test. Results: It was observed that the baseline values of heart rate in follicular phase was (78.8 ±7.48) while in luteal (84 ± 8.17), SBP in follicular phase (113.9 ± 6.63) while luteal phase (115.8 ±5.91), DBP was (72.8 ±6.90) in the follicular phase and (76.5 ± 6.82) in the luteal phase. MVC at 30% was maintained for 1, 2 and 4 mins and it was observed that all the values of HR, SBP and DBP were higher in the luteal phase. The rate of fall to baseline for all the cardiovascular parameters i.e.HR, SBP and DBP were higher in the follicular phase compared to the luteal phase. Conclusion: The results suggest a greater sympathetic activity during the luteal phase to a bout of static isometric exercise hence it can be inferred that the sex steroids lend themselves to an interaction with the ANS indirectly reflecting in cardiovascular system functioning. Keywords: ANS, Isometric, Gonadal, Oestrogen, Vagal.

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Introduction: The cyclical fluctuating gonadal hormones in a female affect the functioning of the autonomic nervous system & a decline in parasympathetic neural activity is a forerunner to multiple cardiac conditions like MI, angina etc hence its detection at its inception is primary to institute remedial measures. Aim: The aim of the present study was to examine whether the cardiac parasympathetic status of a healthy eumenorrhic female is altered during different phases of menstrual cycle. Materials and Methods- Thirty eumenorrhic females were recruited during the follicular and luteal phases of menstrual cycle & subjected to battery of parasympathetic autonomic tests. Statistical Analysis: Data was analyzed statistically using student’s paired t-test. Results: The results from 30:15 ratio in follicular phase was (1.19 ±0.05) while in luteal (1.08 ±0.05  ), E:I ratio in follicular ( 1.58 ±0.15 ) while in luteal phase was (1.29 ±0.25), Valsalva ratio in follicular (1.89 ±0.32 ) while in luteal phase was (1.73 ±0.34 )while the values of DBD and Tachycardia ratio were insignificant statistically. Conclusion: We hence conclude that there is an obvious interaction between the gonadal hormones and autonomic nervous system which is reflected by a reduced vagal outflow during luteal phase. Keywords: Autonomic, Deep Breathing difference, Menstrual cycle, Parasympathetic, Vagal.

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