Dynamics of Respiratory Parameters in Young Women During the Menstrual Cycle

<jats:p>The menstrual cycle is a natural physiological process in women. Changes in hormone levels in their bodies during different phases of the cycle affect the respiratory system. However, literature data indicate that this issue has not been sufficiently studied. The purpose of this article was to investigate the dynamics of respiratory parameters during different phases of the menstrual cycle. Methods. Respiratory parameters were measured daily for two consecutive menstrual cycles in 15 women aged 20–25 years using a computer-based spirometer Spiro-Spectrum (Neurosoft, Russia). Results. Maximal values of the respiratory rate (RR) and tidal volume (TV) were observed in the luteal phase (LP) of the menstrual cycle (p &lt; 0.01). Minute volume, which is derived from RR and TV, reached a maximum in the middle of LF and a minimum at the end of the follicular phase (FP) (p &lt; 0.01). The highest values of vital capacity (VC) and forced VC were observed at the beginning of LP, while the lowest, in the middle of FP (p &lt; 0.01 and p &lt; 0.05, respectively). The analysis of changes in peak expiratory flow, reflecting bronchial conduction, showed that this parameter increased by the beginning of LP and reached a minimum at the end of FP (p &lt; 0.01). A similar pattern was observed with other parameters reflecting bronchial conduction: forced expiratory volume in the 1st second (FEV1) and the FEV1/VC ratio. The value of maximal voluntary ventilation (MVV) was higher in the LP (p &lt; 0.05). During the MVV test, RR was minimal at the end of FP and increased by the beginning of LP (p &lt; 0.01). The study of the conductivity of bronchi of different diameters found a significant change in the conductivity of only large-diameter bronchi in the early LP. Thus, the research established significant changes in both static and dynamic parameters of external respiration in young women in the course of the menstrual cycle.</jats:p>