The effect of the menstrual cycle on running economy

Menstrual Cycle Phases Influence on Cardiorespiratory Response to Exercise in Endurance-Trained Females

“…Outcomes from the present study are supported by previous research, which observed menstrual cycle effect on this variable. Specifically, elevated values of Ve during the MLP compared to the LFP [8] and to the EFP [26] were reported. Authors from these studies agree in the fact that increments in cardiorespiratory variables occur during the MLP due to progesterone´s peak in this phase.…”

“…Authors from these studies agree in the fact that increments in cardiorespiratory variables occur during the MLP due to progesterone´s peak in this phase. On the one hand, there is a strong basis in evidence that high levels of progesterone enhance the chemosensitivity of the hypothalamus chemoreceptors, lowering the threshold of the medullary respiratory centre, and this in turn increases Ve [1,3,8,[26][27][28][29], which may be accompanied by a rise in VO 2 [8,26]. In addition, due to the presence of progesterone receptors in the hypoglossal nuclei, this sex hormone relaxes bronchial smooth muscles and reduces respiratory muscles contractions [27], which may account for the increase in flow rate and Ve [29].…”

“…Once the warm-up finished, the speed was set at 8 km/h and then increased by 0.2 km/h every 12 s until exhaustion. A slope of 1% was set throughout the test to simulate air resistance [8]. The maximal aerobic speed was considered as the minimum speed required to elicit the VO 2 peak [16].…”

“…Thereby, other than reproductive functions, these hormones may influence many other physiological systems such as hypothalamus, cardiovascular system, kidney tubules, liver, skeletal muscle and adipose tissue [1,[3][4][5], which may have an impact on females' exercise performance. In this sense, an increase in ventilation (Ve) has been reported in sedentary [6] and active females [7,8] as well as an increase in heart rate (HR) in both, sedentary [9] and trained females [10], during the luteal phase. In addition, higher fat utilisation in the luteal phase has been observed in active females, resulting in a lower respiratory exchange ratio (RER) during this phase [4].…”

“…These conflicting findings may be explained by methodological shortcomings, mainly the measurements trials carried out in different moments of the menstrual cycle since it has been divided into two [12,13], three [8,10] or four [6,11] phases. An additional limitation is the menstrual cycle verification, as studies often rely on calendar counting [4,11,12] or measuring body basal temperature [4], and it is well known than these methods are not accurate enough and should be accompanied by urinary LH tests and serum sex hormone verification, as a recent review concluded [3].…”