Exercise Performance Is Impaired during the Midluteal Phase of the Menstrual Cycle

Female Exercise Metabolism: Quality Assessment of Existing Knowledge Base and Key Challenges in Study Design

A better understanding of the practical and methodological challenges inherent in accurately tracking female hormonal status would enhance the clarity of research findings in exercise metabolism. The purpose of this study was to conduct an objective assessment of the quality of existing literature in this area and to provide a general overview of the practical conditions and issues encountered in studies investigating substrate metabolism during exercise in women, both in those using (HC+) or not using (HC-) hormonal contraceptives. Forty-four articles were identified through systematic reviews, meta-analyses, and searches on PubMed/MEDLINE. A quality assessment framework was developed and applied using a double-blind scoring approach. The loss/exclusion of data between baseline and final analyses per study was quantified, and the main challenges were highlighted. A higher mean global score was observed in studies conducted among HC+ women (81%) than those among HC- women (46%). Although the dropout rates were rarely mentioned in HC+ women articles, the mean rate of participant/data loss in HC- groups was 22.1%. The rate of HC- participant loss was positively correlated with the global score (r = .504, p = .02). High-quality research may be easier to achieve in studies involving HC+ women compared with those involving HC- women. Studies on HC- women seem to face more practical challenges, such as tracking the menstrual cycle and targeting specific (sub)phases of the menstrual cycle, along with technical and feasibility limitations. Thus, although the framework for designing such studies exists, the quality assessment of the available literature emphasizes its challenge in terms of research implementation.

Effect of Beetroot Juice Supplementation on Aerobic Capacity in Female Athletes: A Randomized Controlled Study

Background/Objectives: This study addresses the growing interest in nutritional supplements that improve athletic performance in endurance sports. Previous research suggests that nitrates in beetroot juice enhance blood vessel dilation and oxygen delivery to muscles. However, the effects of these nitrates on cardiopulmonary performance in female athletes remain underexplored. The aim of this study was to evaluate the effect of beetroot juice supplementation on aerobic work capacity in female endurance athletes. Methods: A cardiopulmonary exercise test (CPET) was conducted to assess aerobic work capacity. Eighteen healthy female endurance athletes (22.9 ± 5.6 years) participated in the study. The participants were randomly assigned to two groups: the control group (placebo group n = 9), which received a nitrate-free placebo beverage, and the experimental group (beetroot juice group n = 9), which consumed 50 mL of beetroot juice concentrate (~6.2 mmol nitrate) two and a half hours before the second test. Results: The results showed that the beetroot juice group demonstrated significant improvements in minute ventilation (VE), respiratory equivalents (VE/VO2 and VE/VCO2), and heart rate (HR) (p < 0.05). Maximal oxygen consumption (VO2 max) increased by 4.82% in the beetroot juice group (from 35.24 ± 5.07 to 36.94 ± 4.91 mL·min-1·kg-1), whereas a small decrease was observed in the placebo group. Conclusions: These findings indicate that beetroot juice may be an effective ergogenic aid, enhancing oxygen utilization and energy production during exercise in female athletes. In terms of practical applications, beetroot juice could contribute to improved athletic performance and serve as a valuable addition to athletes' nutritional plans. Future studies should explore the long-term effects, optimal dosages, and duration of supplementation in larger and more diverse populations.

Affective Responses to Acute Exercise: A Meta-Analysis of the Potential Beneficial Effects of a Single Bout of Exercise on General Mood, Anxiety, and Depressive Symptoms

OBJECTIVE

Acute exercise elicits various biobehavioral and psychological responses, but results are mixed with regard to the magnitude of exercise-induced affective reactions. This meta-analysis examines the magnitude of general mood state, anxiety, and depressive symptom responses to acute exercise while exploring exercise protocol characteristics and background health behaviors that may play a role in the affective response.

METHODS

A total of 2770 articles were identified from a MEDLINE/PubMed search and an additional 133 articles from reviews of reference sections. Studies had to have measured general mood before the acute exercise bout and within 30 minutes after exercise completion. Effect sizes were estimated using Hedges' g , with larger values indicating improvement in the outcome measure.

RESULTS

A total of 103 studies were included presenting data from 4671 participants. General mood state improved from preexercise to postexercise ( g = 0.336, 95% confidence interval [CI] = 0.234-0.439). Anxiety ( g = 0.497, 95% CI = 0.263-0.730) and depressive symptoms ( g = 0.407, 95% CI = 0.249-0.564) also improved with exercise. There was substantial and statistically significant heterogeneity in each of these meta-analyses. This heterogeneity was not explained by differences in participants' health status. Meta-regression analyses with potential moderators (intensity of exercise, mode of exercise, usual physical activity level, or weight status of participants) also did not reduce the heterogeneity.

CONCLUSION

This meta-analysis shows significantly improved general mood, decreased anxiety, and lower depressive symptoms in response to an acute bout of exercise. There was substantial heterogeneity in the magnitude of the effect sizes, indicating that additional research is needed to identify determinants of a positive affective response to acute exercise.

The Dose-Response in Elite Soccer: Preliminary Insights From Menstrual-Cycle Tracking During the FIFA Women's World Cup 2019

PURPOSE

This preliminary study examined the influence of estimated menstrual-cycle (MC) phase on responses to soccer matches and training sessions in preparation for and during the FIFA (Fédération internationale de football association) Women's World Cup 2019.

METHODS

Twenty outfield players representing a national team were tracked over a 45-day period. External (10-Hz global positioning system; total and distance covered at high-metabolic power [≥20 W·kg-1]) and internal load measures (minutes ≥80% heart-rate maximum, sessional ratings of perceived exertion) were collected during all training and matches, with single-item wellness measures (fatigue, soreness, sleep quality, and sleep duration) collected each morning prior to activity. MC phase was estimated individually via an algorithm, informed from pretournament survey responses and ongoing symptom reporting (FitrWoman). Model comparison statistics were used to determine the impact of estimated MC phase in nonhormonal contraceptive users (n = 16).

RESULTS

Sessional rating of perceived exertion responses to total distances ≥5 km were higher during the luteal phase (+0.6-1.0 au; P ≤ .0178) versus menstruation (phase 1), but no other observable dose-response trends were observed. Sleep, fatigue, and soreness ratings were not typically associated with MC phase, with the exception of exacerbated fatigue ratings in luteal versus follicular phase 48 hours postmatch (-0.73 au, P = .0275).

CONCLUSIONS

Preliminary findings suggest that estimated MC phase may contribute to the understanding of the dose-response to soccer training and matches.

Menstrual cycle hormones and oral contraceptives: a multimethod systems physiology-based review of their impact on key aspects of female physiology

Hormonal changes around ovulation divide the menstrual cycle (MC) into the follicular and luteal phases. In addition, oral contraceptives (OCs) have active (higher hormone) and placebo phases. Although there are some MC-based effects on various physiological outcomes, we found these differences relatively subtle and difficult to attribute to specific hormones, as estrogen and progesterone fluctuate rather than operating in a complete on/off pattern as observed in cellular or preclinical models often used to substantiate human data. A broad review reveals that the differences between the follicular and luteal phases and between OC active and placebo phases are not associated with marked differences in exercise performance and appear unlikely to influence muscular hypertrophy in response to resistance exercise training. A systematic review and meta-analysis of substrate oxidation between MC phases revealed no difference between phases in the relative carbohydrate and fat oxidation at rest and during acute aerobic exercise. Vascular differences between MC phases are also relatively small or nonexistent. Although OCs can vary in composition and androgenicity, we acknowledge that much more work remains to be done in this area; however, based on what little evidence is currently available, we do not find compelling support for the notion that OC use significantly influences exercise performance, substrate oxidation, or hypertrophy. It is important to note that the study of females requires better methodological control in many areas. Previous studies lacking such rigor have contributed to premature or incorrect conclusions regarding the effects of the MC and systemic hormones on outcomes. While we acknowledge that the evidence in certain research areas is limited, the consensus view is that the impact of the MC and OC use on various aspects of physiology is small or nonexistent.

The Influence of Menstrual-Cycle Phase on Measures of Recovery Status in Endurance Athletes: The Female Endurance Athlete Project

PURPOSE

To investigate the influence of menstrual-cycle (MC) phase on measures of recovery status, that is, resting heart rate, perceived sleep quality, and physical and mental readiness to train, among female endurance athletes.

METHODS

Daily data were recorded during 1 to 4 MCs (ie, duration ≥21 and ≤35 d, ovulatory, luteal phase ≥10 d) of 41 trained-to-elite-level female endurance athletes (mean [SD]: age 27 [8] y, weekly training: 9 [3] h). Resting heart rate was assessed daily using a standardized protocol, while perceived sleep quality and physical and mental readiness to train were assessed using a visual analog scale (1-10). Four MC phases (early follicular phase [EFP], late follicular phase, ovulatory phase, and midluteal phase [MLP]) were determined using the calendar-based counting method and urinary ovulation-prediction test. Data were analyzed using linear mixed-effects models.

RESULTS

Resting heart rate was significantly higher in MLP (1.7 beats·min-1, P = .006) compared with EFP without significant differences between the other MC phases. Perceived sleep quality was impaired in MLP compared with late follicular phase (-0.3, P = .035). Physical readiness to train was lower both in ovulatory phase (-0.6, P = .015) and MLP (-0.5, P = .026) compared with EFP. Mental readiness to train did not show any significant differences between MC phases (P > .05).

CONCLUSIONS

Although significant, the findings had negligible to small effect sizes, indicating that MC phase is likely not the main determinant of changes in measures of recovery status but, rather, one of the many possible stressors.

Trunk variability and local dynamic stability during gait after generalized fatigue induced by incremental exercise test in young women in different phases of the menstrual cycle

Purpose

The purpose of this study was to identify how generalized fatigue along with hormonal changes throughout the menstrual cycle affects trunk variability and local dynamic stability during gait.

Methods

General fatigue was induced by an incremental test on a treadmill, and the menstrual cycle was divided into three phases: follicular, ovulatory, and luteal. Twenty-six healthy, young volunteers (aged 18 to 28 years) who did not use oral contraceptives or other hormonal drugs with a regular menstrual cycle participated in the study. They walked on the treadmill for 4 min at the preferred speed, before the incremental test, followed by four sets of 4 min alternating between walking, also at preferred speed, and resting. From trunk kinematic data, the following were extracted: the mean of the standard deviation along strides, as a measure of variability, and the maximum Lyapunov exponent, as a measure of local dynamic stability (LDS).

Results

After the incremental test, variability increased, and LDS decreased. However, they showed a tendency to return to the initial value faster in women compared to previous results for men. In the follicular phase, which has less hormonal release, the volunteers had an almost complete recovery in LDS soon after the first rest interval, suggesting that female hormones can interfere with fatigue recovery. Nevertheless, concerning the LDS, it was significantly lower in the luteal phase than in the follicular phase.

Conclusion

Women that are not taking oral contraceptives should be aware that they are susceptible to increased gait instabilities in the pre-menstrual phase after strenuous activities.

Exploring the relationship between nutritional intake and menstrual cycle in elite female athletes

This study aimed to examine potential variations in nutritional intake among female athletes, including top-level, throughout the menstrual cycle. A total 122 female athletes participated in the study, documenting their food consumption over a 3-day period. The menstrual status of female athletes was also assessed, and using the survey results, the phase of the menstrual cycle (the follicular, early luteal, or late luteal) during which each meal was recorded was determined. Consequently, the meal records were categorized into the respective three phases. The findings of this study indicated that there were no notable disparities in nutritional intake, encompassing energy, protein, fat, carbohydrate, calcium, iron, and fiber, across the three phases of the menstrual cycle. The results imply that female athletes may experience comparatively smaller variations in nutrient intake related to the menstrual cycle. This could be attributed to the higher energy requirements of female athletes because of their rigorous training. This study underscores the significance of accounting for the population when examining nutrient intake changes associated with the menstrual cycle.

Fluid balance during physical work in the heat is not modified by the menstrual cycle when fluids are freely available

We tested the hypothesis that women may be more at risk of becoming dehydrated during physical work in the heat in the early follicular phase (EF), compared with the late follicular (LF) and mid-luteal (ML) phases of the menstrual cycle when allowed free access to drink. Twelve healthy, eumenorrheic, unacclimated women (26 ± 5 yr) completed three trials (EF, LF, and ML phases) involving 4 h of exposure to 33.8 ± 0.8 °C, 54 ± 1% relative humidity. Each hour, participants walked on a treadmill for 30 min at a rate of metabolic heat production of 338 ± 9 W. Participants drank a cool, flavor-preferred non-caloric sport drink ad libitum. Nude body weight was measured pre- and post-exposure, and percent changes in body weight loss were interpreted as an index of changes in total body water. Total fluid intake and urine output were measured and sweat rate was estimated from changes in body mass corrected for fluid intake and urine output. Fluid intake was not different between phases (EF: 1,609 ± 919 mL; LF: 1,902 ± 799 mL; ML: 1,913 ± 671; P = 0.202). Total urine output (P = 0.543) nor sweat rate (P = 0.907) differed between phases. Percent changes in body mass were not different between phases (EF: -0.5 ± 0.9%; LF: -0.3 ± 0.9%; ML: -0.3 ± 0.7%; P = 0.417). This study demonstrates that the normal hormonal fluctuations that occur throughout the menstrual cycle do not alter fluid balance during physical work in the heat.NEW & NOTEWORTHY The effect of the menstrual cycle on fluid balance during physical work in the heat when fluids are freely available is unknown. This study demonstrates that fluid balance is not modified in women across three distinct phases of the menstrual cycle during physical work in the heat These results indicate that when women have free access to cool fluid during physical work in the heat, they respond similarly across all three phases to maintain fluid homeostasis across the menstrual cycle.

The exercise power-duration relationship is equally reproducible in eumenorrheic female and male humans

This study aims to investigate the effect of the menstrual cycle (MC) on exercise performance across the power-duration relationship (PDR). We hypothesized females would exhibit greater variability in the PDR across the MC than males across a similar timespan, with critical power (CP) and work-prime (W') being lower during the early follicular phase than the late follicular and midluteal phases. Seven eumenorrheic, endurance-trained female adults performed multiple constant-load-to-task-failure and maximum-power tests at three timepoints across the MC (early follicular, late follicular, and midluteal phases). Ten endurance-trained male adults performed the same tests approximately 10 days apart. No differences across the PDR were observed between MC phases (CP: 186.74 ± 31.00 W, P = 0.955, CV = 0.81 ± 0.65%) (W': 7,961.81 ± 2,537.68 J, P = 0.476, CV = 10.48 ± 3.06%). CP was similar for male and female subjects (11.82 ± 1.42 W·kg^-1 vs. 11.56 ± 1.51 W·kg^-1, respectively) when controlling for leg lean mass. However, W' was larger (P = 0.047) for male subjects (617.28 ± 130.10 J·kg^-1) than female subjects (490.03 ± 136.70 J·kg^-1) when controlling for leg lean mass. MC phase does not need to be controlled when conducting aerobic endurance performance research on eumenorrheic female subjects without menstrual dysfunction. Nevertheless, several sex differences in the power-duration relationship exist, even after normalizing for body composition. Therefore, previous studies describing the physiology of exercise performance in male subjects may not perfectly describe that of female subjects.NEW & NOTEWORTHY Females are often excluded from exercise performance research due to experimental challenges in controlling for the menstrual cycle (MC), causing uncertainty regarding how the MC impacts female performance. The present study examined the influences that biological sex and the MC have on the power-duration relationship (PDR) by comparing critical power (CP), Work-prime (W'), and maximum power output (P_MAX) in males and females. Our data provide evidence that the MC does not influence the PDR and that females exhibit similar reproducibility as males. Thus, when conducting aerobic endurance exercise research on eumenorrheic females without menstrual dysfunction, the phase of the MC does not need to be controlled. Although differences in body composition account for some differences between the sexes, sex differences in W' and P_MAX persisted even after normalizing for different metrics of body composition. These data highlight the necessity and feasibility of examining sex differences in performance, as previously generated male-only data within the literature may not apply to female subjects.

Influence of Menstrual Cycle or Hormonal Contraceptive Phase on Physiological Variables Monitored During Treadmill Testing

Purpose: To examine the influence of menstrual cycle (MC) and hormonal contraceptive (HC) cycle phases on physiological variables monitored during incremental treadmill testing in physically active women (eumenorrheic, EUM = 16 and monophasic HC-users, CHC = 12).

Methods: Four running tests to exhaustion were performed at bleeding, mid follicular (mid FOL)/active 1, ovulation/active 2, and mid luteal (mid LUT)/inactive. HC and MC phases were confirmed from serum hormones. Heart rate (HR), blood lactate (Bla), and V˙O₂ were monitored, while aerobic (AerT) and anaerobic (AnaT) thresholds were determined. V˙O_2peak, maximal running speed (RUN_peak), and total running time (RUN_total) were recorded.

Results: No significant changes were observed in V˙O₂ or Bla at AerT or AnaT across phases in either group. At maximal effort, absolute and relative V˙O_2peak, RUN_peak, and RUN_total remained stable across phases in both groups. No significant fluctuations in HR_max were observed across phases, but HR at both AerT and AnaT tended to be lower in EUM than in CHC across phases.

Conclusion: Hormonal fluctuations over the MC and HC do not systematically influence physiological variables monitored during incremental treadmill testing. Between group differences in HR at AerT and AnaT underline why HR-based training should be prescribed individually, while recording of MC or HC use when testing should be encouraged as phase may explain minor, but possibly meaningful, changes in, e.g., Bla concentrations or differences in HR response.

Moving beyond inclusion: Methodological considerations for the menstrual cycle and menopause in research evaluating effects of dietary nitrate on vascular function

Recent reports have acknowledged the underrepresentation of women in the field of dietary nitrate (NO₃^-) research. Undoubtedly, greater participation from women is warranted to clarify potential sex differences in the responses to dietary NO₃^- interventions. However, careful consideration for the effects of sex hormones - principally 17β-estradiol - on endogenous nitric oxide (NO) synthesis and dietary NO₃^- reductase capacity is necessary for improved interpretation and reproducibility of such investigations. From available literature, we present a narrative review describing how hormonal variations across the menstrual cycle, as well as with menopause, may impact NO biosynthesis catalyzed by NO synthase enzymes and NO₃^- reduction via the enterosalivary pathway. In doing so, we address methodological considerations related to the menstrual cycle and hormonal contraceptive use relevant for the inclusion of premenopausal women along with factors to consider when testing postmenopausal women. Adherence to such methodological practices may explicate the utility of dietary NO₃^- supplementation as a means to improve vascular function among women across the lifespan.

Modelling menstrual cycle length in athletes using state-space models

The ability to predict an individual's menstrual cycle length to a high degree of precision could help female athletes to track their period and tailor their training and nutrition correspondingly. Such individualisation is possible and necessary, given the known inter-individual variation in cycle length. To achieve this, a hybrid predictive model was built using data on 16,524 cycles collected from a sample of 2125 women (mean age 34.38 years, range 18.00-47.10, number of menstrual cycles ranging from 4 to 53). A mixed-effect state-space model was fitted to capture the within-subject temporal correlation, incorporating a Bayesian approach for process forecasting to predict the duration (in days) of the next menstrual cycle. The modelling procedure was split into three steps (1) a time trend component using a random walk with an overdispersion parameter, (2) an autocorrelation component using an autoregressive moving-average model, and (3) a linear predictor to account for covariates (e.g. injury, stomach cramps, training intensity). The inclusion of an overdispersion parameter suggested that [Formula: see text] [Formula: see text] of cycles in the sample were overdispersed. The random walk standard deviation for a non-overdispersed cycle is [Formula: see text] [1.00, 1.09] days while under an overdispersed cycle, the menstrual cycle variance increase in 4.78 [4.57, 5.00] days. To assess the performance and prediction accuracy of the model, each woman's last observation was used as test data. The root mean square error (RMSE), concordance correlation coefficient and Pearson correlation coefficient (r) between the observed and predicted values were calculated. The model had an RMSE of 1.6412 days, a precision of 0.7361 and overall accuracy of 0.9871. In conclusion, the hybrid model presented here is a helpful approach for predicting menstrual cycle length, which in turn can be used to support female athlete wellness.

Impact of Nutrition-Based Interventions on Athletic Performance during Menstrual Cycle Phases: A Review

Despite the steady increase in female participation in sport over the last two decades, comprehensive research on interventions attenuating the influence of female menstrual physiology on performance remains scarce. Studies involving eumenorrheic women often only test in one menstrual phase to limit sex hormone variance, which may restrict the application of these findings to the rest of the menstrual cycle. The impacts of nutrition-based interventions on athletic performance throughout the menstrual cycle have not been fully elucidated. We addressed this gap by conducting a focused critical review of clinical studies that reported athletic outcomes as well as menstrual status for healthy eumenorrheic female participants. In total, 1443 articles were identified, and 23 articles were included. These articles were published between 2011 and 2021, and were retrieved from Google Scholar, Medline, and PubMed. Our literature search revealed that hydration-, micronutrient-, and phytochemical-based interventions can improve athletic performance (measured by aerobic capacity, anaerobic power, and strength performance) or attenuate exercise-induced damage (measured by dehydration biomarkers, muscle soreness, and bone resorption biomarkers). Most performance trials, however, only assessed these interventions in one menstrual phase, limiting the application throughout the entire menstrual cycle. Improvements in athletic performance through nutrition-based interventions may be contingent upon female sex hormone variation in eumenorrheic women.

Hormonal Contraceptive Use in Football Codes in Australia

The recent launch of the new National elite women's football competitions in Australia has seen a 20-50% increase in grassroots female participation. With the growing participation across grassroots to elite competitions, understanding the health of female athletes should be prioritized. In elite level athletes, hormonal contraceptive (HC) use is common (~50%), however, little is known about the prevalence and reasons for use and disuse of HC in elite female football athletes. As such, the impact of HC use is often not considered when monitoring the health of female footballers. This study involved a subset of data collected as part of a larger questionnaire investigating menstrual cycle function, hormonal contraception use, and the interaction with training load volume and perceived performance in elite female football code athletes. A total of 177 participants completed the questionnaire across three football codes within Australia (rugby league, rugby union/sevens, Australian football). One third (n = 58) of athletes were currently using HC, predominately in the form of an oral contraceptive pill (OC, n = 47). Reasons for use included: to avoid pregnancy (71%); to control/regulate cycle (38%); and to reduce menstrual pain (36%). However, most athletes using an OC (89%) could not identify the type of pill used (e.g., mono-, bi-, or triphasic). The main reason for disuse was due to the negative side effects (n = 23), such as mood swings, weight gain, and depression/anxiety. Comparing HC users and non-users, there were no statistical differences in the number of reported menstrual symptoms, use of medication to relieve menstrual pain, or frequency for needing to adapt training due to their menstrual cycle (p > 0.05). Since most athletes were unaware of the type of OC they used, female football athletes require further education about the different types of HC, and specifically OC, available to them. Similarities in the symptoms experienced, pain management, and training adaptation requirements between groups suggests that HC use may not have the intended outcome for certain athletes. As such, greater awareness of athlete's personal experiences with the menstrual cycle, how HC may influence their experience, and acknowledgment of non-pharmacological methods to help manage menstrual cycle related symptoms are warranted.

Prevalence and frequency of menstrual cycle symptoms are associated with availability to train and compete: a study of 6812 exercising women recruited using the Strava exercise app

OBJECTIVES

The menstrual cycle can affect sports participation and exercise performance. There are very few data on specific menstrual cycle symptoms (symptoms during various phases of the cycle, not only during menstruation) experienced by exercising women. We aimed to characterise the most common symptoms, as well as the number and frequency of symptoms, and evaluate whether menstrual cycle symptoms are associated with sporting outcomes.

METHODS

6812 adult women of reproductive age (mean age: 38.3 (8.7) years) who were not using combined hormonal contraception were recruited via the Strava exercise app user database and completed a 39-part survey. Respondents were from seven geographical areas, and the questions were translated and localised to each region (Brazil, n=892; France, n=1355; Germany, n=839; Spain, n=834; UK and Ireland, n=1350; and USA, n=1542). The survey captured exercise behaviours, current menstrual status, presence and frequency of menstrual cycle symptoms, medication use for symptoms, perceived effects of the menstrual cycle on exercise and work behaviours, and history of hormonal contraception use. We propose a novel Menstrual Symptom index (MSi) based on the presence and frequency of 18 commonly reported symptoms (range 0-54, where 54 would correspond to all 18 symptoms each occurring very frequently).

RESULTS

The most prevalent menstrual cycle symptoms were mood changes/anxiety (90.6%), tiredness/fatigue (86.2%), stomach cramps (84.2%) and breast pain/tenderness (83.1%). After controlling for body mass index, training volume and age, the MSi was associated with a greater likelihood of missing or changing training (OR=1.09 (CI 1.08 to 1.10); p≤0.05), missing a sporting event/competition (OR=1.07 (CI 1.06 to 1.08); p≤0.05), absenteeism from work/academia (OR=1.08 (CI 1.07 to 1.09); p≤0.05) and use of pain medication (OR=1.09 (CI 1.08 to 1.09); p≤0.05).

CONCLUSION

Menstrual cycle symptoms are very common in exercising women, and women report that these symptoms compromise their exercise participation and work capacity. The MSi needs to be formally validated (psychometrics); at present, it provides an easy way to quantify the frequency of menstrual cycle symptoms.

Sex Differences in Exercise-Induced Bronchoconstriction in Athletes: A Systematic Review and Meta-Analysis

Exercise-induced bronchoconstriction (EIB) is a common complication of athletes and individuals who exercise regularly. It is estimated that about 90% of patients with underlying asthma (a sexually dimorphic disease) experience EIB; however, sex differences in EIB have not been studied extensively. With the goal of better understanding the prevalence of EIB in males and females, and because atopy has been reported to occur at higher rates in athletes, in this study, we investigated sex differences in EIB and atopy in athletes. A systematic literature review identified 60 studies evaluating EIB and/or atopy in post-pubertal adult athletes (n = 7501). Collectively, these studies reported: (1) a 23% prevalence of EIB in athletes; (2) a higher prevalence of atopy in male vs. female athletes; (3) a higher prevalence of atopy in athletes with EIB; (4) a significantly higher rate of atopic EIB in male vs. female athletes. Our analysis indicates that the physiological changes that occur during exercise may differentially affect male and female athletes, and suggest an interaction between male sex, exercise, and atopic status in the course of EIB. Understanding these sex differences is important to provide personalized management plans to athletes with underlying asthma and/or atopy.