Changes in sympathovagal balance during menstural cycle

The natural cyclical changes in hormone levels during reproductive years of women have profound effects on various system of body. This provides an excellent opportunity to study the effects of hormone of physiology of various system of body. The levels of oestrogen and progesterone are low just before the beginning of each menstruation. Then specific changes in the hormonal levels during premenstrual and menstrual periods of the cycle can lead to various physiological changes in the body. Many studies have focused on the physiological reactivity to mental challenge in relationship to the risk of cardio-vascular disease [1]. Some investigators have suggested that physiological functions fluctuate with the menstrual cycle [2,3] and others have observed no menstrual phase effects [4,5]. Our study findings indicate that sympathetic nervous, activities in the luteal phase of menstrual cycle is greater than in the follicular phase, whereas parasympathethic nervous activity is predominant in Follicular phase. A difference in the balance of ovarian hormone may be responsible for these changes during menstrual cycle.