CARDIAC STRUCTURE AND FUNCTION AT REST AND DURING EXERCISE ACROSS THE MENSTRUAL CYCLE IN HEALTHY FEMALES

Abstract

During the menstrual cycle, fluctuations in oestrogen and progesterone concentrations occur. In the early-follicular phase, there are low concentrations of both oestrogen and progesterone, the late-follicular phase sees peak levels of oestrogen with low concentrations of progesterone, and the mid-luteal phase has high concentrations of both hormones. These significantly different hormone concentrations have been hypothesised to affect cardiac function and structure at rest and exercise, and the associated physiological mechanisms during exercise performance. The aim of the present study was to assess blood pressure and left ventricular structure and cardiac function during rest and exercise across the three phases of the menstrual cycle. 12 healthy eumennorheic females (mean ± s; 23.9 ± 3.4 years; height 167.1 ± 7.0 cm and body mass 62.5 ± 9.5 kg) with regular menstrual cycles (29.3 ± 2.6 days) underwent testing during the early-follicular, late-follicular and mid-luteal phases of their cycle. During rest and a supine cycling bout at 70% maximal aerobic power, blood pressure, collected using a beat-by-beat arterial blood monitoring system, and left ventricular structure and function parameters, collected using echocardiography, were measured. One way ANOVA statistical tests and two way repeated measures ANOVA statistical tests were used to analyse data (P = <0.05). There were no significant differences found between any parameters across the three phases of the menstrual cycle. The findings from the present study conclude that the fluctuations of female steroid hormones across the menstrual cycle have no affect on cardiac structure and function or blood pressure at rest and during exercise.