Cardiorespiratory Responses to Endurance Exercise Over the Menstrual Cycle and With Oral Contraceptive Use

Abstract

Female steroid hormone fluctuations during the menstrual cycle and exogenous hormones from oral contraceptives may have potential effects on exercise performance. The aim of this study was to investigate the effects of these fluctuations on cardiorespiratory responses during steady-state exercise in women. Twenty-three healthy endurance-trained women performed 40 minutes of running at 75% of their maximal aerobic speed during different phases of the menstrual cycle (n 5 15; early follicular phase, midfollicular phase, and luteal phase) or oral contraceptive cycle (n 5 8; hormonal phase and nonhormonal phase). Ventilatory parameters and heart rate (HR) were measured. Data were analyzed using a mixed linear model. For the eumenorrheic group, significantly higher oxygen uptake (p 5 0.049) and percentage of maximum oxygen uptake (p 5 0.035) were observed during the midfollicular phase compared with the early follicular. Heart rate (p 5 0.004), oxygen ventilatory equivalent (p 5 0.042), carbon dioxide ventilatory equivalent (p 5 0.017), and tidal volume (p 5 0.024) increased during luteal phase in comparison with midfollicular. In oral contraceptive users, ventilation (p 5 0.030), breathing frequency (p 5 0.018), oxygen ventilatory equivalent (p 5 0.032), and carbon dioxide ventilatory equivalent (p 5 0.001) increased during the hormonal phase. No significant differences were found for the rest of the parameters or phases. Both the eumenorrheic group and oral contraceptive group showed a significant increase in some ventilatory parameters during luteal and hormonal phases, respectively, suggesting lower cardiorespiratory efficiency. However, the lack of clinical meaningfulness of these differences and the nondifferences of other physiological variables, indicate that the menstrual cycle had a small impact on submaximal exercise in the current study.

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

“…Concretely, HR showed lower values in the EFP compared to the LFP. Likewise, a recent research conducted with endurance trained females reported higher values of HR during the MLP compared to the mid-follicular phase [10]. This study also reported increments in body basal temperature during this phase and, as aforementioned, it may be accompanied by an increase in HR [3,30] and Ve [6,22,26]..…”

“…They suggested that the increase in cardiorespiratory strain due to high intensity exercise is greater than any possible increase caused by progesterone. Hence, progesterone effect on this physiological variable may be masked by the high intensity exercise [3,10,31]. Thus, discrepancies in results could be related with the intensity of the protocols.…”

“…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].…”

Menopause Delays the Typical Recovery of Pre-Exercise Hepcidin Levels after High-Intensity Interval Running Exercise in Endurance-Trained Women

“…On the same day, after feeding and resting (a minimum of 2 h after feeding), participants performed a maximal ramp test on a computerized treadmill (H/P/COSMOS 3PW 4.0, H/P/Cosmos Sports & medical gmbh, Nussdorf-Traunstein, Germany) to determine each participant's peak oxygen consumption ( . VO 2peak ) [41]. The laboratory environmental conditions were 708.7 ± 4.9 mmHg, 22.8 ± 1.6 • C and 72.9 ± 6.6% of relative atmospheric humidity.…”