Effect Of Menstrual Cycle Phase Research Articles

Influence of Menstrual Phase and Symptoms on Match Running in Professional Footballers.

This study examined the effects of menstrual cycle phases and symptoms on match running performance in football (soccer) players. Twenty-one nonhormonal contraceptive using football players from four professional teams were monitored for up to four menstrual cycles during a domestic league season. Menstrual phases, classified as early-follicular phase (EFP), mid-late follicular phase (MFP), and luteal phase (LP), were determined by self-reporting of menstruation and urinary hormone tests (luteinizing hormone and pregnanediol-3-glucuronide). On match day, players completed a menstrual symptom severity questionnaire. In repeated matches, players wore 10 Hz Global Positioning Satellite (GPS) devices to measure relative (/min) total distance, high-speed running distance, very high-speed distance, peak speed, acceleration count, and deceleration count. Linear mixed models were performed for each GPS measure to determine the relationship with phase or symptoms. Data for 7 and 10 players were included for menstrual phase and menstrual symptoms analyses, respectively. A significantly higher total distance was reported during MFP compared to EFP (Δ 5.1 m min-1; p = 0.04) and LP (Δ 5.8 m min-1; p = 0.007). Significantly greater high-speed running was reported during MFP compared to EFP (Δ 1.2 m min-1; p = 0.012) and LP (Δ 1.1 m min-1; p = 0.007). No significant effect of menstrual phase was found for any other GPS measures (p > 0.05). Accelerations declined with increasing symptom severity (p = 0.021, estimate = -0.01count.min-1). Menstrual symptom severity did not affect any other GPS measures (p > 0.05). In conclusion, greater total distance and high-speed running occurred during the MFP. Additionally, accelerations minimally decreased with increasing menstrual symptom severity. Large intra- and inter-variability existed, suggesting individualized monitoring and management of menstrual effects on performance would be beneficial.

Menstrual cycle phase differences in myofiber damage and macrophage infiltration following electrical stimulation-induced muscle injury.

The purpose of this study was to examine the effects of menstrual cycle phase on myofiber injury, regenerative events and inflammation after electrical-stimulation (ES) induced myofiber damage. 28 premenopausal women (21.3 ± 2 yrs) were randomized into an early follicular (EF; N=14) or late follicular (LF; N = 14) group. After menstrual cycle tracking and phase confirmation, subjects underwent 200 electrically stimulated eccentric muscle contractions one week after providing a muscle biopsy. 7 days post-ES, subjects provided a final biopsy. Primary outcomes included: serum estradiol, indirect markers of muscle damage, direct indicators of myofiber necrosis and regeneration, satellite cell number, and macrophage infiltration. Women in the LF group had higher serum estradiol (122.1 ± 23.4 vs. 81.7 ± 30.8 pg/ml; P<0.001)compared to the EF group on the day of ES. Whereas the EF group recovered baseline maximal isometric strength by 4 days post-ES, the LF group did not. Only women in the LF group showed significant and consistent evidence of myofiber necrosis and regeneration pre- to post-ES. Despite showing more evidence of myofiber damage, women in the LF group also experienced reduced total and CD206+ macrophage infiltration relative to the EF group. Satellite cell quantity increased significantly post-ES in both groups, with no differences between groups. Collectively, the data suggest that the high estrogen LF phase may be associated with increased susceptibility to myofiber injury while also limiting the subsequent intramuscular inflammatory response.

Attentional bias to alcohol-related cues: effects of menstrual cycle phase and sex differences.

A recent study by our group found that women displayed greater attentional bias to alcohol-related cues during the late versus early follicular phase in both sober and intoxicated states, suggesting a greater risk of excessive drinking among women during this phase. Changes in attentional bias as a function of menstrual cycle phase raise questions about potential sex differences in the relative consistency by which women and men display attentional bias to alcohol over time. The present study tested sex differences in attentional bias to alcohol by comparing the change in women's attentional bias from early to late follicular phase to that observed in men over the same period. Twenty-five men and 25 women aged 21-32 participated in a placebo-controlled study examining sex differences in the rewarding properties of alcohol. Participants completed measures of attentional bias to alcohol-related cues during two sessions following both 0.6g/kg alcohol and placebo. Test sessions occurred one week apart, and for female participants coincided with the early and late follicular phases. Men consistently displayed attentional bias to alcohol-related cues across sessions under both doses. By contrast, women showed attentional bias only during the late follicular phase, at a magnitude greater than that observed in men, and persistent under both doses. These findings highlight the potential role of sex and menstrual cycle phase in sensitizing drinkers to rewarding properties of alcohol-related cues. Men's motivation to drink may remain relatively consistent, whereas women may be most motivated during the late follicular phase.

Menstrual Cycle Variations in Wearable-Detected Finger Temperature and Heart Rate, But Not in Sleep Metrics, in Young and Midlife Individuals.

Most studies about the menstrual cycle are laboratory-based, in small samples, with infrequent sampling, and limited to young individuals. Here, we use wearable and diary-based data to investigate menstrual phase and age effects on finger temperature, sleep, heart rate (HR), physical activity, physical symptoms, and mood. A total of 116 healthy females, without menstrual disorders, were enrolled: 67 young (18-35 years, reproductive stage) and 53 midlife (42-55 years, late reproductive to menopause transition). Over one menstrual cycle, participants wore Oura ring Gen2 to detect finger temperature, HR, heart rate variability (root mean square of successive differences between normal heartbeats [RMSSD]), steps, and sleep. They used luteinizing hormone (LH) kits and daily rated sleep, mood, and physical symptoms. A cosinor rhythm analysis was applied to detect menstrual oscillations in temperature. The effect of menstrual cycle phase and group on all other variables was assessed using hierarchical linear models. Finger temperature followed an oscillatory trend indicative of ovulatory cycles in 96 participants. In the midlife group, the temperature rhythm's mesor was higher, but period, amplitude, and number of days between menses and acrophase were similar in both groups. In those with oscillatory temperatures, HR was lowest during menses in both groups. In the young group only, RMSSD was lower in the late-luteal phase than during menses. Overall, RMSSD was lower, and number of daily steps was higher, in the midlife group. No significant menstrual cycle changes were detected in wearable-derived or self-reported measures of sleep efficiency, duration, wake-after-sleep onset, sleep onset latency, or sleep quality. Mood positivity was higher around ovulation, and physical symptoms manifested during menses. Temperature and HR changed across the menstrual cycle; however, sleep measures remained stable in these healthy young and midlife individuals. Further work should investigate over longer periods whether individual- or cluster-specific sleep changes exist, and if a buffering mechanism protects sleep from physiological changes across the menstrual cycle.

Effects of the Menstrual Cycle and Hormonal Contraceptive Use on Metabolic Outcomes, Strength Performance, and Recovery: A Narrative Review.

The effects of female sex hormones on optimal performance have been increasingly recognized as an important consideration in exercise and sport science research. This narrative review explores the findings of studies evaluating the effects of menstrual cycle phase in eumenorrheic women and the use of hormonal contraception (oral contraceptives and hormonal intrauterine devices) on metabolism, muscular strength, and recovery in active females. Ovarian hormones are known to influence metabolism because estrogen is a master regulator of bioenergetics. Importantly, the menstrual cycle may impact protein synthesis, impacting skeletal muscle quality and strength. Studies investigating muscular strength in eumenorrheic women report equivocal findings between the follicular phase and luteal phase with no differences compared to oral contraceptive users. Studies examining recovery measures (using biomarkers, blood lactate, and blood flow) do not report clear or consistent effects of the impact of the menstrual cycle or hormonal contraception use on recovery. Overall, the current literature may be limited by the evaluation of only one menstrual cycle and the use of group means for statistical significance. Hence, to optimize training and performance in females, regardless of hormonal contraception use, there is a need for future research to quantify the intra-individual impact of the menstrual cycle phases and hormonal contraceptive use in active females.

Differential changes in appetite hormones post-prandially based on menstrual cycle phase and oral contraceptive use: A preliminary study

This was a preliminary study that examined whether appetite regulation is altered during the menstrual cycle or with oral contraceptives. Ten naturally cycling females (NON-USERS) and nine tri-phasic oral contraceptive using females (USERS) completed experimental sessions during each menstrual phase (follicular phase: FP; ovulatory phase: OP; luteal phase: LP). Appetite perceptions and blood samples were obtained fasted, 30, 60, and 90 min post-prandial to measure acylated ghrelin, active glucagon-like peptide-1 (GLP-1), and total peptide tyrosine tyrosine (PYY). Changes were considered important if p < 0.100 and the effect size was ≥medium. There appeared to be a three-way (group x phase x time) interaction for acylated ghrelin where concentrations appeared to be greater in USERS versus NON-USERS during the OP 90-min post-prandial and during the LP fasted, and 90-min post-prandial. In USERS, ghrelin appeared to be greater 90-min post-prandial in the OP versus the FP with no other apparent differences between phases. There were no apparent differences between phases in NON-USERS. There appeared to be a three-way interaction for PYY where concentrations appeared to be greater in USERS during the FP 60-min post-prandial and during the OP 30-min post-prandial. In USERS PYY appeared to be greater 60-min post-prandial during the OP versus the LP with no other apparent differences. There were no apparent differences between phases in NON-USERS. There appeared to be no effect of group or phase on GLP-1, or appetite perceptions. These data demonstrate small effects of menstrual cycle phase and oral contraceptive use on the acylated ghrelin and total PYY response to a standardized meal, with no effects on active GLP-1 or perceived appetite, though more work with a large sample size is necessary.

Effects of menstrual cycle phases on heart rate variability indicators and external respiratory function of female Muay Thai athletes

Effects of menstrual cycle phases on heart rate variability indicators and external respiratory function of female Muay Thai athletes

Lightness Peaks during the Menstrual Phase: A Retrospective Challenge to a Visual Arousal Theory of Estrogen

(1) Background: The influence of estrogen on cognitive and perceptual functions is debated. Some research suggests that estrogen increases arousal, improving cognitive function, while others propose that increased arousal might reduce performance in certain tasks. This study investigates the effects of menstrual cycle phase and estrogen levels on lightness perception in cycling women and hormonal contraceptive (HC) users. (2) Methods: Sixteen women (nine with natural cycles and seven HC users) completed three sessions aligned with different menstrual cycle phases. During these sessions, participants adjusted the luminance of five test stimuli (representing blue, green, green-yellow, yellow, and red) until they matched a flickering reference white stimulus. Lightness was calculated as the ratio of the reference stimulus luminance (5 cd/m2) divided by the test luminance required to match. Estrogen levels were also determined for each participant from saliva samples collected on the morning of each session. The effects of wavelength and menstrual cycle phase on lightness perception were analyzed, followed by post hoc comparisons and correlations between lightness perception and estrogen levels for both cycling women and HC users. (3) Results: Lightness varied by menstrual phase (MCP) in cycling women and was slightly higher during the low estrogen menstrual phase compared to peri-ovulation or luteal phases. In HC users, lightness measures were equivalent across phases. For cycling women, lightness was negatively correlated with estrogen for the green and green-yellow stimuli. There were no such associations among HC users. (4) Conclusions: This report challenges the concept that high estrogen phases of the menstrual cycle always positively influence perception. Conversely, these results revealed that—at least in cycling, non-hormonal contraceptive users—lightness perception was both at a maximum during the low estrogen menstrual phase and negatively associated with estrogen levels across all tested wavelengths.

Reproducible stability of verbal and spatial functions along the menstrual cycle

Recent studies have reported brain changes in response to ovarian hormonal fluctuations along the menstrual cycle. However, it remains unclear, whether these brain changes are of an adaptive nature or whether they are linked to changes in behavior along the menstrual cycle, particularly with respect to cognitive performance. To address this knowledge gap, we report results from 3 well-powered behavioral studies with different task designs, leveraging the advantages of each design type. In all three studies we assessed whether verbal or spatial performance (i) differed between cycle phases, (ii) were related to estradiol and / or progesterone levels and (iii) were moderated by individual hormone sensitivity as estimated by premenstrual symptoms. Overall, results of all three studies point towards a null effect of menstrual cycle phase and – to a lesser extent – ovarian hormones on verbal and spatial performance and provided no evidence for a moderation of this effect by individual hormone sensitivity. We conclude that there is substantial consistency in verbal and spatial performance across the menstrual cycle, and that future studies of intra-individual variation are needed.

Effect of Menstrual Cycle Phase and Hormonal Contraceptives on Resting Metabolic Rate and Body Composition.

The cyclical changes in sex hormones across the menstrual cycle (MC) are associated with various biological changes that may alter resting metabolic rate (RMR) and body composition estimates. Hormonal contraceptive (HC) use must also be considered given their impact on endogenous sex hormone concentrations and synchronous exogenous profiles. The purpose of this study was to determine if RMR and dual-energy X-ray absorptiometry body composition estimates change across the MC and differ compared with HC users. This was accomplished during a 5-week training camp involving naturally cycling athletes (n = 11) and HC users (n = 7 subdermal progestin implant, n = 4 combined monophasic oral contraceptive pill, n = 1 injection) from the National Rugby League Indigenous Women's Academy. MC phase was retrospectively confirmed via serum estradiol and progesterone concentrations and a positive ovulation test. HC users had serum estradiol and progesterone concentrations assessed at the time point of testing. Results were analyzed using general linear mixed model. There was no effect of MC phase on absolute RMR (p = .877), relative RMR (p = .957), or dual-energy X-ray absorptiometry body composition estimates (p > .05). There was no effect of HC use on absolute RMR (p = .069), relative RMR (p = .679), or fat mass estimates (p = .766), but HC users had a greater fat-free mass and lean body mass than naturally cycling athletes (p = .028). Our findings suggest that RMR and dual-energy X-ray absorptiometry body composition estimates do not significantly differ due to changes in sex hormones in a group of athletes, and measurements can be compared between MC phases or with HC usage without variations in sex hormones causing additional noise.

Effects of menstrual cycle phases on elasticity index in female soccer players

Effects of menstrual cycle phases on elasticity index in female soccer players

Effects of menstrual cycle phase and ovulation on the salivary cortisol awakening response

The cortisol awakening response (CAR) is influenced by several state and trait variables, one of which might be the menstrual cycle in women. Previous results suggested that the CAR is enhanced around ovulation, which is why it has been recommended to avoid sampling during the ovulatory phase. In two separate studies, we aimed to replicate previous findings that reported the CAR’s modulation across the menstrual cycle, especially during ovulation. In Study 1, a group of 27 healthy naturally cycling women collected saliva at 0, 30, 45, and 60 min post-awakening on two days during their follicular, ovulatory, and luteal phases in a repeated measures design. In Study 2, CAR samples were collected from 30 healthy naturally cycling women on seven consecutive days around the expected ovulation. To increase reliability of CAR measurements, participants' compliance of saliva sampling times was monitored, ovarian steroids (estradiol and progesterone) were collected, and ovulation was confirmed with specific test kits. Contrary to our expectations, we detected no differences in the CAR over the menstrual cycle, and no significant association with variations in estradiol and progesterone. In addition, we excluded confounding effects such as compliance and validated the cycle phase. These results suggest that the CAR is largely robust against hormonal variations across the menstrual cycle, including the mid-cycle phase around ovulation. However, further research is needed to understand the potential ovarian steroid-induced modulation of HPA axis functioning and the menstrual cycle’s effects on salivary cortisol levels in psychobiological studies.

Does Phase of the Menstrual Cycle Affect Balance and Postural Control?

. The aim of the study is to examine the effects of menstrual cycle phases (MCP) on balance and postural control. The study was carried out with 63 volunteer women. Digital ovulation kits and, a Menstrual Cycle Regularity Questionnaire (MCRQ) to detect menstrual cycle regularity and duration, Premenstrual Syndrome Questionnaire (PMSQ) to question the presence of premenstrual syndrome, Menstruation Attitude Questionnaire (MAQ) to assess menstrual attitudes, International Physical Activity Questionnaire Short Form (IPAQ-SF) to question physical activity level was used. Balance and postural oscillation were evaluated with Balance Master balance and performance test device and Tekscan MatScan™ Pressure Mat System, respectively. All evaluations were repeated twice, in the preovulatory period and the postovulatory period. When the evaluations of the preovulatory period and the postovulatory period were compared, there was %3 increase in the percent weight-bearing of the non-dominant extremity (p = 0.01) and %2.5 decrease in the percent weight-bearing of the dominant limb in the postovulatory period (p = 0.01). %8 increase in functional reach distances was detected in the postovulatory period (p < 0.01). It was determined that there was %7.4 decrease in the oscillation rate of the center of gravity in the static stance with eyes open and %9 decrease in the static stance with eyes closed in the postovulatory period (p = 0.35, p = 0.18, respectively). It has been determined that the balance and postural control of young women are negatively affected in the preovulatory period and the function improved from the preovulatory period to the postovulatory period.

The effects of menstrual cycle phases on immune function and inflammation at rest and after acute exercise: A systematic review and meta-analysis.

The immune system plays an important role in mediating exercise responses and adaptations. However, whether fluctuating hormone concentrations across the menstrual cycle may impact these processes remains unknown. The aim of this systematic review with meta-analysis was to compare baseline concentrations as well as exercise-induced changes in immune and inflammatory parameters between menstrual cycle phases. A systematic literature search was conducted according to the PRISMA guidelines using Pubmed/MEDLINE, ISI Web of Science, and SPORTDiscus. Of the 159 studies included in the qualitative synthesis, 110 studies were used for meta-analysis. Due to the designs of the included studies, only the follicular and luteal phase could be compared. The estimated standardized mean differences based on the random-effects model revealed higher numbers of leukocytes (-0.48 [-0.73; -0.23], p < 0.001), monocytes (-0.73 [-1.37; -0.10], p = 0.023), granulocytes (-0.85 [-0.1.48; -0.21], p = 0.009), neutrophils (-0.32 [-0.52; -0.12], p = 0.001), and leptin concentrations (-0.37 [-0.5; -0.23], p = 0.003) in the luteal compared to the follicular phase at rest. Other parameters (adaptive immune cells, cytokines, chemokines, and cell adhesion molecules) showed no systematic baseline differences. Seventeen studies investigated the exercise-induced response of these parameters, providing some indications for a higher pro-inflammatory response in the luteal phase. In conclusion, parameters of innate immunity showed cycle-dependent regulation at rest, while little is known on the exercise responses. Due to a large heterogeneity and a lack of cycle phase standardization among the included studies, future research should focus on comparing at least three distinct hormonal profiles to derive more specific recommendations for exercise prescription.

Menstrual Cycle Modulation of Neural Reward Responsiveness and its Associations with Anhedonia

During their childbearing years, women are nearly twice as likely as men to be diagnosed with depression. Despite this stark sex difference, there is a dearth of research examining the effects of the menstrual cycle and ovarian hormones on neural mechanisms underlying depression. Reduced neural reward responsiveness is linked to depression and anhedonia, and prior studies suggest that reward responsiveness may be modulated by ovarian hormones. In a sample of 74 naturally-cycling undergraduate women, the present study employed a within-subject design and multilevel modeling to examine effects of menstrual cycle phases (i.e., early follicular, periovulatory, and mid-luteal phases) and ovarian hormones (i.e., estradiol and progesterone) on an EEG measure of neural reward sensitivity—the Reward Positivity (RewP)—and associations between the RewP and anhedonia. Anhedonia scores were collected at a baseline session and the RewP and salivary hormone concentrations were collected once in each cycle phase. While the RewP did not vary by cycle phase, the RewP was most enhanced when both estradiol and progesterone were above the intra-individual average. Additionally, women with elevated anhedonia were characterized by a reduced RewP in the periovulatory phase as compared to the mid-luteal phase. Finally, the negative association between the RewP and anhedonia was strongest in the periovulatory phase. The present findings suggest that distinct patterns of variability in the RewP across the menstrual cycle may be associated with anhedonia. Future work should further examine these possibilities via longitudinal designs and hormone administration studies.

Skeletal muscle regeneration at different phases of the menstrual cycle

INTRODUCTION: The effect of estrogen on muscle function and recovery from damage has been studied, but the effects of estrogen fluctuations during the menstrual cycle on muscle regeneration remain inconclusive. PURPOSE: The purpose of this study was to examine the effects of menstrual cycle phases on muscle regeneration after electrically stimulated muscle damage. We hypothesized that muscle damage during the late follicular (LF) phase results in better muscle regeneration as compared to muscle damage during the early follicular (EF) phase. METHODS: 23 premenopausal females (21.3±2 yrs) were recruited and split into two groups, EF and LF. After menstrual cycle tracking and phase confirmation, subjects underwent 200 electrically stimulated eccentric muscle contractions one week after providing a muscle biopsy. 7 days after inducing muscle damage, the subjects reported to give a final biopsy. Sections from muscle samples were stained for markers of laminin, dystrophin, satellite cells (SCs; Pax7), nuclei, total macrophages (CD68), and anti-inflammatory macrophages (CD206/CD68). Data for SCs, and %CD206+CD68+ cells are presented as mean±SD, and damaged fibers and CD206+CD68+ cells/fiber are presented as median±interquartile range. RESULTS: Electrical stimulation caused muscle fiber necrosis (0.005±0.018 damaged fiber/fiber, p=0.0002) as measured by the laminin-containing and dystrophin-deficient fibers. There was no difference between EF and LF groups for the number of damaged fibers (p=0.055) Muscle damage resulted in ~200% increase in the total number of CD68+ macrophages (p=0.008), and ~ 40% increase in the number of SCs (p=0.001) in both groups. However, there was no significant difference between EF and LF groups for the change in total macrophages per fiber (p=0.07) or SCs/fiber (p=0.25) in response to electrically stimulated muscle damage. Anti-inflammatory macrophages increased by about 104%±127 in EF and 240%±390 in LF group, but the difference between groups was not significant (p=0.39). A comparison of the proportion of anti-inflammatory macrophages per total macrophages before and one week after muscle damage did not show any time effect (p=0.25), which could indicate the regenerative and anti-inflammatory state of skeletal muscle one week after damage. CONCLUSION: Contrary to our hypothesis, our data indicate that skeletal muscle regeneration is not affected by different phases of the menstrual cycle. However, this finding is limited to only some of the markers of regeneration one week after muscle damage. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of menstrual cycle phase and sex on wave reflections and wasted pressure effort in healthy young adults

Early return of arterial wave reflections can increase aortic systolic pressure, left ventricular wasted pressure effort (WPE), and cardiovascular disease risk and mortality. Naturally menstruating premenopausal women experience cyclic fluctuations in female sex hormones that have known cardioprotective effects. Whether these cycle-dependent hormonal fluctuations alter wave reflections and WPE in women or contribute to sex differences is largely unknown. PURPOSE To determine the effect of menstrual cycle phase and biological sex on wave reflection indices and WPE in healthy young adults. HYPOTHESIS Premenopausal women would have favorable changes in wave reflection indices and reduced WPE during high-hormone menstrual cycle phases compared to the low-hormone phase and to men. METHODS Thirteen naturally menstruating women (27±6 yrs; cycle length, 30±6 days) and 7 age-matched men (28±4 yrs), underwent repeated vascular testing. Women were tested during the low-hormone early follicular phase (Visit 1, cycle day 4±2), high-estrogen late follicular phase (Visit 2, cycle day 13±3) and high-progesterone mid-luteal phase (Visit 3, cycle day 23±4). Men’s visits were time-matched to women’s visits. Aortic pressure waves were generated using a generalized transfer function applied to tonometry-derived radial pressure waves. Left ventricular outflow tract diameter and aortic flow velocities were recorded using echocardiography. Pressure-flow alignment and wave separation analyses were performed offline and used to compute maximal forward (Pf) and backward (Pb) pulse wave amplitudes, reflection magnitude (RM=Pb/Pf), reflected wave transit time (RWTT, apparent return of Pb), and WPE. Carotid-femoral pulse wave velocity (PWV) was measured as an index of arterial stiffness. RESULTS Sex by visit interactions were observed for Pb (p=0.02), RM (p=0.04), and WPE (p=0.003). Premenopausal women showed reductions from the early follicular phase to the mid-luteal phase (i.e., Visit 1 vs. Visit 3) in Pb (11±1 vs. 10±1 mmHg, p=0.03), RM (45±7 vs. 42±6%, p=0.05), and WPE (2644 vs. 1984 mmHg·ms, p=0.002) but there were no differences across visits in men (p&gt;0.05 for all). No significant interactions or main effects were observed for Pf, RWTT, or PWV (p&gt;0.05 for all). CONCLUSION Wave reflection indices Pb and RM and left ventricular WPE show favorable reductions in the high-progesterone mid-luteal phase of a natural menstrual cycle. Importantly, these reductions in premenopausal women were not mirrored in men, implicating the role of female sex hormones. Studies of wave reflections and WPE in naturally menstruating premenopausal women should control for menstrual cycle phase. Supported by American Heart Association Grant 826955 and National Institutes of Health grant P20GM113125 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Effect of Menstrual-Cycle Phase on Immune Responses to a 5-km Cycling Time Trial: An Exploratory Study.

Exercise has transient effects on the immune system that could influence infection risk and tissue recovery after exercise. Little is known about how the menstrual cycle interacts with the immune responses to acute exercise. This exploratory study sought to evaluate the effect of menstrual-cycle phase on peripheral blood mononuclear cell counts before and immediately after a bout of intense aerobic exercise. Seven naturally menstruating women (age: 27 [3]y) completed three 5-km cycling time trials coinciding with the early-follicular, late-follicular, and mid-luteal stage, confirmed by hormonal measurement. Venous blood samples were taken and examined for the presence of immune cell types using flow cytometry. Reductions in circulating CCR7+CD45RA+ naïve CD4+ T cells, CD4+CD25+ regulatory T cells, and CD56+CD57+ natural killer cells observed during the early-follicular phase were attenuated when exercise was performed during the late-follicular phase. Similarly, reductions in circulating CD56+CD57+ natural killer cells and CD14+TLR4+ monocytes following exercise in the early-follicular phase were abolished when exercise was performed in the midluteal phase. These preliminary findings indicate that the effect of acute high-intensity exercise on immune-cell mobilization and activation varies across the menstrual cycle, potentially impacting the anti-inflammatory effects of regulatory T cells and the cell-mediated effects of both natural killer CD57+ cells and monocytes expressing TLR4.

Hormonal status effects on the electrophysiological correlates of performance monitoring in women

Fluctuations in ovarian hormones are thought to play a role in the increased prevalence of mood and anxiety disorders in women. Error-related negativity (ERN) and error positivity (Pe) are two putative electrophysiological biomarkers for these internalizing disorders. We investigated whether female hormonal status, specifically menstrual cycle phase and oral contraceptive (OC) use, impact ERN and Pe. Additionally, we examined whether the relationship between the ERN and negative affect (NA) was moderated by hormonal status and tested whether the ERN mediated the relation between ovarian hormones and NA. Participants were healthy, pre-menopausal women who were naturally cycling (NC) or using OCs. Using a counterbalanced within-subject design, all participants performed a speeded-choice reaction-time task twice while undergoing electroencephalography measurements. NC women (N = 42) performed this task during the early follicular and midluteal phase (when estrogen and progesterone are both low and both high, respectively), while OC users (N = 42) performed the task during active OC use and during their pill-free week. Estradiol and progesterone levels were assessed in saliva. Comparing the two cycle phases within NC women revealed no differences in the (Δ)ERN, (Δ)Pe or NA. We did observe a negative relation between phase-related changes in the ΔERN and changes in NA. Mediation analysis additionally showed that phase-related changes in estradiol were indirectly and negatively related to NA through a reduction of ΔERN amplitudes. When comparing active OC users with NC women, we observed increased ΔPe- but not (Δ)ERN amplitudes in the former group. No evidence was found for moderating effects of menstrual cycle phase or OC use on the relation between the ERN and NA. These findings suggest that hormonal status may impact the neural correlates of performance monitoring and error sensitivity, and that this could be a potential mechanism through which ovarian hormones influence mood.

Dietary energy intake across the menstrual cycle: a narrative review.

Females are often underrepresented in the scientific literature, but awareness of the need for female-specific research is increasing. Review articles have been published on the effects of the menstrual cycle on aspects of exercise performance and physiology, yet to date no research has reviewed the effect of menstrual cycle phase on dietary energy intake. Fluctuations in endogenous sex hormones across the menstrual cycle influence a range of physiological processes, including those involved in nutritional status. Observational research typically quantifies female athletes' nutritional intakes at a single time point; however, this may provide inaccurate information if dietary intake fluctuates across the menstrual cycle. Similarly, this may have implications for interventional research, where dietary intake is often poorly controlled or monitored. This review aimed to synthesize the published literature on dietary energy intakes of naturally menstruating females in various phases of the menstrual cycle. The review critiques the relevant literature in light of recent publications on good practice for female research, explores the impact of the menstrual cycle on energy intake, identifies gaps within the evidence base, and informs future research. Overall, energy intake appears to be lower in the follicular phase compared with the luteal phase, with a particular decrease in the days leading up to and including ovulation. The magnitude of these fluctuations is not yet clearly quantifiable and most likely varies, both between individuals, and from cycle to cycle. This review notes the lack of high-quality research investigating the energy intakes of females across the menstrual cycle, and the very limited data available for female athletes and others who undertake large amounts of physical activity. It also highlights the need for researchers to take into consideration anovulatory cycles and the potential effects of premenstrual disorders on dietary intake.