Inconsistencies in the perceived impact of the menstrual cycle on sport performance and in the prevalence of menstrual cycle symptoms: A scoping review of the literature

Exploring the gut-exercise link: A systematic review of gastrointestinal disorders in physical activity

BACKGROUND

The relationship between exercise and gastrointestinal (GI) health is complex and bidirectional. While moderate exercise generally promotes gut health by enhancing motility, reducing inflammation, and supporting microbial balance, intense or prolonged physical activity may exacerbate GI symptoms, particularly in individuals with pre-existing digestive disorders. A deeper understanding of this interplay is essential for optimizing both exercise performance and GI well-being.

AIM

To synthesize current evidence on exercise-related GI disorders, exploring the prevalence, mechanisms, risk factors, and management strategies associated with exercise-induced GI symptoms.

METHODS

Following PRISMA guidelines, comprehensive searches of databases, including PubMed, Scopus, Web of Science, and EMBASE were conducted. Studies were included if they focused on exercise-induced GI disorders, encompassed randomized controlled trials, cohort studies, case-control studies, and cross-sectional designs, and addressed symptoms across various exercise modalities. Data were extracted and analyzed to identify patterns and implications for clinical and athletic practice.

RESULTS

A total of 231 studies met the inclusion criteria, highlighting both the benefits and risks of exercise on GI health. Regular moderate-intensity exercise, including activities such as walking, cycling, and yoga has been associated with improved GI function in conditions like gastroesophageal reflux disease, irritable bowel syndrome, inflammatory bowel disease, and constipation. These benefits are attributed to enhanced intestinal motility, reduced systemic inflammation, and improved gut barrier integrity. Additionally, exercise plays a role in regulating the gut-brain axis, with practices like yoga and Tai Chi demonstrating particular effectiveness in alleviating functional GI disorders. Conversely, high-intensity or prolonged exercise may contribute to symptoms such as nausea, diarrhea, and abdominal pain due to mechanisms like splanchnic hypoperfusion and increased intestinal permeability. Individual factors, including fitness level, dietary habits, hydration status, and underlying GI conditions, significantly influence the body’s response to exercise.

CONCLUSION

Moderate-intensity exercise is a beneficial and well-tolerated intervention for promoting GI health, whereas high-intensity activities require careful monitoring, particularly in individuals with pre-existing GI disorders. Personalized exercise and dietary strategies are essential for balancing the benefits of physical activity with the risk of GI distress. Further research is needed to explore the long-term effects of exercise on gut microbiota composition and overall digestive health.

Adolescents, menstruation, and physical activity: insights from a global scoping review

BACKGROUND

Adolescent girls tend to be less physically active than boys, a trend that coincides with puberty. Menstruation may act as a barrier to physical activity, which in turn may influence menstrual symptoms. The purpose of this scoping review was to synthesise the global literature on the association between menstruation and physical activity among adolescents.

METHODS

A systematic search was conducted across five databases, identifying studies on menstruation and physical activity in adolescents (aged 10-18 years) without date restrictions. Studies not in English, including only athlete populations and focusing solely on premenstrual syndrome were excluded. Titles and abstracts, followed by full texts were screened by two independent reviewers.

RESULTS

Eighty-six studies were included, spanning 33 countries. Thematic synthesis of data from the selected studies suggests a bidirectional relationship in that menstruation may act as a barrier to physical activity due to symptoms, societal stigma and menstrual product access, while physical activity may alleviate symptoms for some. The review highlights variability in study methodologies, with most relying on self-report data.

CONCLUSION

This review provides insights into the varied experiences of adolescent girls' physical activity and menstruation, influenced by cultural, social, and resource-related factors. It makes important and timely recommendations for the direction of future research, which should employ longitudinal and mixed methods approaches to better understand the association between menstruation and physical activity in this population and address gaps regarding the mechanisms and magnitude of this relationship.

The menstrual cycle minimally affects cardiorespiratory function and body balance control in trained women during acute hypobaric hypoxia exposure (4000 m)

PURPOSE

The impact of the menstrual cycle (MC) on physical performance has been a hot topic in recent years, due to the increasing professionalisation of women's sports. This study set out to investigate the impact of the MC on the performance of women athletes in a hypoxic environment. The study focused on cardiovascular responses, respiratory function, and postural control as key indicators of sports performance.

METHODS

We measured the physiological responses in 20 participants under hypobaric hypoxia (HH) conditions, on two occasions: during the early follicular phase (F) and in the mid-luteal phase (L). Spirometry and postural control parameters at rest were evaluated at sea level and 4000 m simulated altitude in a hypobaric chamber. The exercise performed at hypoxia was divided into two phases of different workload intensities: 40% and 70% of their theoretical maximal rate of oxygen consumption (V ˙ O 2 max ), followed by a recovery period.

RESULTS

Tidal volume (VT) significantly decreased at the L phase compared to the F during high intensity exercise (1.69 vs. 1.82, p ≤ 0.05) and arterial oxygen saturation (SaO2) was greater in the L phase versus F independently of the exercise intensity (p ≤ 0.01) under hypoxic conditions. Meanwhile, spirometry and other cardiorespiratory responses did not change across the MC. Lateral velocity increased in the L phase with eyes open compared to F (4.88 vs. 4.24, p ≤ 0.05). No significant differences in the performance metrics evaluated between the menstrual cycle phases or between exercise intensities were detected.

CONCLUSION

Our data confirms that the menstrual cycle in women does not generate sufficiently marked alterations to affect sports performance when acutely exposed to high altitudes.

Perceptions and experiences of the menstrual cycle amongst elite adult and adolescent football players

The purpose of this study was to investigate players' experiences and perceptions of the menstrual cycle (MC) and the perceived impact on performance. Female elite adult (n = 31, age 24.6 ± 5.1 years) and adolescent (n = 65, age 15.0 ± 1.1 years) players completed an online questionnaire consisting of quantitative and qualitative questions. MC symptoms were experienced by 90.1% naturally menstruating participants (86.9% adolescents and 93.6% adults (x2 = 1.53, df = 2, p = 0.47, n = 92)), and 78.3% adolescents perceived their MC impacts performance, compared to 96.4% adults (x2 = 4.54, df = 1, p = 0.033, n = 74). Physical symptoms, psychological symptoms and energy levels were cited as key reasons for the MC negatively impacting performance. Challenges in communicating MC experiences were reported by 44.92% (n = 23) adolescents compared to 20.0% (n = 6) adults (x2 = 7.29, df = 2, p = 0.026, n = 82), with a perceived lack of knowledge, ability to relate and awkwardness cited as key reasons. Football players report wellbeing and performance impacts due to their MC, highlighting the need for individual understanding and support. Furthermore, understanding the experiences of adolescents enables the development of targeted support structures that equip them with tools to manage and communicate about their MC, and hopefully preventing issues as they become senior players.

Validity and Sensitivity of a Submaximal Fitness Test for Assessing Cardiorespiratory Fitness and Response to Preseason Training Load in Female Football Players

PURPOSE

To evaluate the within-athlete sensitivity, validity, and dose-response relationships of exercise heart rate (HRex) from a submaximal fitness test (SMFT) as a proxy measure of cardiorespiratory fitness.

METHODS

This study follows an observational, repeated-measures design. Twenty-five trained female football players' training loads (GPS and HR metrics) were collected throughout an 8-week preseason period. A 4-minute continuous-fixed SMFT protocol was administered weekly to evaluate HRex. A running time-trial assessment was conducted in weeks 2 and 8 to calculate mean velocity (5-min-30-s time-trial mean velocity) as a proxy measure of cardiorespiratory fitness. SMFT HRex measurement properties were determined via within- and between-athletes correlations and linear mixed models.

RESULTS

The overall preseason change in SMFT HRex derived from weekly repeated measures was -4.7% points (90% CIs, -3.9 to -5.6). The association between SMFT HRex and 5-minute-30-second time-trial mean velocity changes was large (-0.55), with 90% CIs ranging from negative moderate to negative very large magnitudes (-0.31 to -0.71). A 1% point decrease in SMFT HRex corresponded to an increase in 5-minute-30-second time-trial mean velocity of 0.13 (90% CIs, 0.03-0.24) km·h-1. Within-athlete correlations between training loads and SMFT HRex demonstrated moderate inverse relationships with external-load parameters (-0.39 to -0.47) and small inverse relationships with HR-based internal metrics (-0.25 to -0.29). Accumulated high- and very high-speed running throughout the entire preseason showed consistent inverse dose-response relationships with SMFT HRex (moderate and large, respectively), while all other load measures displayed unclear associations.

CONCLUSIONS

SMFT HRex is a sensitive and valid tool to evaluate preseason cardiorespiratory-fitness changes in female football players.

Perceived Negative Menstrual Cycle Symptoms, But Not Changes in Estrogen or Progesterone, Are Associated with Impaired Cycling Race Performance

PURPOSE

To examine the relationship between menstrual cycle (MC) phase-dependent fluctuations of estrogen and progesterone and virtual cycling race performance, with a secondary aim of correlating perceived MC-related symptoms with performance.

METHODS

In a novel observational study design, 37 female cyclists/triathletes not using any hormonal contraception completed one virtual cycling race (19.5-km time trial (TT)) per week across a 1-month period (totaling four races). Participants completed MC characterization and tracking, including urinary ovulation kits, across two complete MCs. Venous blood samples were collected within 21 h of racing to determine serum 17-β-estradiol and progesterone concentrations, as well as an assessment of self-reported, perceived race-day MC and gastrointestinal (GI) symptoms, which were all then correlated to race performance.

RESULTS

There was no relationship between race completion time and individual estradiol ( r = -0.001, P = 0.992) or progesterone ( r = -0.023, P = 0.833) concentrations. There was no difference between race time between MC phases (follicular/luteal, P = 0.238), whether MC bleeding or not bleeding ( P = 0.619), and whether ovulating or not ovulating ( P = 0.423). The total number of perceived MC symptoms recorded on race day was positively correlated to increased race time ( r = 0.268 (95% confidence interval, 0.056-0.457), P = 0.014), as was the number of GI symptoms of at least "moderate" severity before the race ( r = 0.233 (95% confidence interval, 0.021-0.425), P = 0.031), but not post-race ( r = 0.022, P = 0.841).

CONCLUSIONS

When implementing a novel, virtual cycling race, fluctuations in ovarian hormone concentrations across the MC do not appear to affect real-world cycling performance among trained cyclists, whereas perceived negative MC and GI symptoms may relate to impaired performance. Therefore, the management of negative MC and GI symptoms appears important for athletic performance enhancement or to mitigate performance decline.

Influence of Menstrual Phase and Symptoms on Sleep Before and After Matches for Professional Footballers

This study investigated the association of menstrual cycle phase and symptoms with objective and subjective sleep measures from professional footballers before and after matches. Twenty-three non-hormonal contraceptive-using professional footballers (from four clubs) were monitored for up to four menstrual cycles during a domestic league season. Menstrual phases (menstruation, mid-late follicular, luteal) were determined using calendar counting and urinary hormone tests (luteinizing hormone and pregnandiol-3-glucuronide). Players rated the severity of 18 symptoms on the evenings of matches and the following two evenings. Individual daily summed menstrual symptom severity (MSS) scores were calculated. Subjective sleep quality was rated the morning of matches and the following two mornings. Objective sleep (bedtime, waketime, total sleep time [TST], sleep onset latency, wake after sleep onset, sleep efficiency) obtained from actigraphy was measured the night prior to (MN-1), of (MN), and following (MN+1) matches. Linear mixed models were performed for each sleep measure to examine the effects of menstrual phase and symptoms. Bedtime was significantly later for MN (p < 0.001), waketime was significantly earlier for MN+1 (p < 0.001), and TST was significantly longer for MN-1 (p < 0.001). Menstrual phase did not have a significant effect on any sleep variable (p > 0.05). Increased MSS score was associated with increased TST (p = 0.03) and increased waketime (p = 0.03). Increased lower back pain severity and mood changes/anxiety severity were associated with increased waketime (p = 0.048) and TST (p = 0.009), respectively. Overall, bedtime and waketime were affected by the night related to matches, with increased TST the night before a match. Menstrual phase was not related to any objective or subjective sleep variables, whilst increasing menstrual symptom severity was related to later waketime and longer TST.

Influence of menstrual cycle and oral contraceptive phases on strength performance, neuromuscular fatigue, and perceived exertion

The primary aim of the study was to assess differences in strength performance, neuromuscular fatigue, and perceived exertion across phases of the menstrual cycle [MC; early follicular (eFP), late follicular (lFP), and mid-luteal phase (mLP)] and oral contraceptives [OCs; active pill phase (aPP) and nonactive pill phase (nPP)]. The secondary aim was to analyze the influence of fluctuating serum 17β-estradiol and progesterone concentrations on these parameters in naturally menstruating women. Thirty-four women (21 with a natural MC and 13 using OCs) completed three or two experimental sessions, respectively. Mean propulsive velocity (MPVmean) and total number of repetitions (REPtotal) were assessed during a power [3 × 8 at 60% 1RM (one-repetition maximum)] and hypertrophy squat loading (3 sets to failure at 70% 1RM), respectively. Changes in bench press and squat MPV at 60% 1RM in response to the loadings were used as surrogates for nonlocal and local fatigue, respectively. Total blood lactate accumulation (BLAA) and markers of perceived exertion were assessed in each session. No significant differences between any of the MC or OC phases were observed for MPVmean, REPtotal, nonlocal and local fatigue, and markers of perceived exertion (all P > 0.050). A higher intraindividual 17β-estradiol concentration was significantly associated with a lower MPVmean (P = 0.019). BLAA was significantly higher in the lFP than in the mLP (P = 0.019) and negatively associated with the intraindividual progesterone concentration (P = 0.005). Although 17β-estradiol may negatively influence the MPV, it appears that fluctuations of both sex hormones across the MC and OC phases are not prominent enough to induce significant or practically relevant changes in the assessed parameters.NEW & NOTEWORTHY Although a high intraindividual 17β-estradiol concentration was associated with a lower movement velocity, markers of strength performance and surrogates for nonlocal and local fatigue remained unaffected by MC and OC phases. Blood lactate accumulation was significantly reduced in the mLP. Furthermore, our findings suggest that the impact of the MC phases varies greatly among individuals. Individuals with high fluctuations in sex hormone concentrations may experience relevant changes in the assessed parameters.

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.

Auditing the Representation of Female Athletes in Sports Medicine Research: Achilles Repair

Background

Establishing evidence-based recommendations specific to female athletes has been overlooked in sports medicine. Achilles tendon rupture is one of the most common musculoskeletal injuries, occurring in 15 to 55 per 100 000 people annually. Differences in injury rates could be due to hormonal effects, as estrogen receptors have been identified in tendons along with decreased tendon strain based on oral contraceptive use. The primary purpose of this study was to audit the representation of female athletes in the literature regarding Achilles repair.

Methods

An electronic search was performed using PubMed to identify articles related to Achilles repair using the protocol by Smith et al. Studies were assessed by population, size, athletic caliber, study impact, research theme, and menstrual status.

Results

Female representation across all studies was 1783 of 10 673 subjects (16.7%). Composition of included studies was predominantly mixed-sex cohorts with 131 of 169 (77.5%) included studies. Within mixed-sex cohort studies, the total representation of female athletes was 1654 of 8792 participants (18.9%). Thirty-two studies were male only, constituting 1540 participants, whereas 3 studies were female only composed of 86 athletes. Importantly, the disparity between male and female representation worsened as the athletic caliber of the study population increased, with 5.0% female representation in studies with professional athletes. No study collected data related to menstrual status and its potential relationship to Achilles rupture or postoperative outcomes.

Conclusion

Mixed-sex cohort studies underrepresented female athletes, and male-only cohort studies were more common than female-only studies. These findings indicate a need for increased representation of female athletes as well as acknowledgment of menstrual status in research related to Achilles repair. Future studies should focus on representation of female athletes and data collection related to sex-specific hormones, hormonal contraceptive use, and menstrual status to improve treatment of Achilles tendon ruptures for female athletes.

Level of Evidence

Level IV, case series.