Sex Hormone Fluctuations Research Articles

Eating disorders of the perimenopause.

Except for psychosis, women's mental health problems across the reproductive lifespan are common. There are periods in a woman's life, associated with significant sex hormone fluctuations, that render her particularly susceptible to mood disturbance and mental health illnesses, including eating disorders. Whilst eating disorders are usually conceptualized as diseases afflicting adolescence and young adults, there is increasing evidence to suggest the landscape for eating disorders has considerably changed and includes a peak in midlife, correlating with the perimenopause. Inpatient admissions and outpatient clinic attendances have increased amongst older women. It is likely this increasing trend is the result of numerous biopsychosocial factors. A diagnosis of an eating disorder in midlife may be more common in those women simultaneously navigating the perimenopause than in midlife women who remain pre-menopausal owing to the significant ovarian hormonal fluctuations encountered in the perimenopause. Eating disorders are serious illnesses associated with significant morbidity and mortality, which are exacerbated when present at older ages. Research is beginning to recognize the importance of including this typically under-represented cohort of middle-aged women in empirical studies, which is critical to a complete etiological understanding. Recognizing and treating these varied presentations and establishing effective treatments for chronic, recurrent and new-onset eating disorders in midlife women is crucial.

Experimentally Elevated Levels of Testosterone Advance Daily Onset of Activity in Short-Day Housed Male House Sparrows (Passer domesticus).

Seasonal changes in sleep/wake cycles and behaviors related to reproduction often co-occur with seasonal fluctuations in sex hormones. Experimental studies have established that fluctuations in circulating testosterone mediate circadian rhythms. However, most studies are performed under constant lighting conditions and fail to investigate the effects of testosterone on the phenotypic output of circadian rhythms, that is, chronotype (daily activity patterns under light:dark cycles). Here, we experimentally elevated testosterone with implants during short nonbreeding daylengths in male house sparrows (Passer domesticus) to test if observed seasonal changes in chronotype are directly in response to photoperiod or to testosterone. We fitted individuals with accelerometers to track activity across treatment periods. Birds experienced three treatments periods: short day photoperiods before manipulation (SD), followed by testosterone implants while still on short days (SD + T). Implants were then removed. After a decrease in cloacal protuberance size, an indicator of low testosterone levels, birds were then photostimulated on long days (LD). Blood samples were collected at night, when testosterone peaks, to compare testosterone levels to daily onset/offset activity for experimental periods. Our results indicate that experimentally elevated testosterone under short nonbreeding photoperiods significantly advanced daily onset of activity and total daily activity relative to daylength. This suggests that testosterone, independent of photoperiod, is responsible for seasonal shifts in chronotypes and daily activity rhythms. These findings suggest that sex steroid hormone actions regulate timing of daily behaviors, likely coordinating expression of reproductive behaviors to appropriate times of the day.

Association of brown adipose tissue activity with circulating sex hormones and fibroblast growth factor 21 in the follicular and luteal phases in young women

BackgroundThermogenesis is influenced by fluctuations in sex hormones during the menstrual cycle in premenopausal women. The thermogenic activity and mass of brown adipose tissue (BAT) are regulated by endocrine factors, including sex hormones and fibroblast growth factor 21 (FGF21). However, the relationship between human BAT and these endocrine fluctuations within individuals remains to be elucidated. This study aimed to assess variations in BAT activity between the luteal and follicular phases and identify correlations with circulating levels of sex hormones and FGF21.MethodsHealthy young women were enrolled in an observational study. Measurement of BAT activity and blood analyses were performed in both the follicular and luteal phases. BAT activity was analyzed using thermography with 2-h cold exposure. Plasma 17β-estradiol, progesterone, and FGF21 levels were determined by enzyme-linked immunosorbent assay. A comparative analysis within individuals was conducted in 13 women to compare the follicular and luteal phases. Furthermore, sensitivity analysis was carried out in 21 women during the follicular phase only.ResultsPlasma 17β-estradiol and progesterone levels were significantly higher in the luteal phase, whereas plasma FGF21 level was significantly higher in the follicular phase. Comparison analysis found no significant differences in cold-induced BAT activity between the follicular and luteal phases in young women. Correlation analysis in both comparison and sensitivity analyses found that plasma 17β-estradiol and progesterone levels were not associated with BAT activity, whereas plasma FGF21 levels were significantly and positively correlated with BAT activity only in the follicular phase. In addition, plasma 17β-estradiol levels in the follicular phase were significantly and positively associated with plasma FGF21 levels in both the comparison and sensitivity analyses.ConclusionsThe thermogenic activity of BAT during cold exposure was comparable between the follicular and luteal phases in young women. Higher BAT activity was associated with elevated levels of plasma FGF21 only in the follicular phase, which is related to increased plasma 17β-estradiol levels.

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.

Research status of hormone replacement therapy on mood and sleep quality in menopausal women

Menopausal syndrome is a common disease of clinical women, which refers to a series of physical and mental symptoms caused by the fluctuation or reduction of sex hormones before and after menopause. Many of these patients have sleep and mood abnormalities that affect their health and quality of life. At present, the understanding of it is gradually improving. This paper mainly analyzes its background and current treatment.

Circadian Rhythms Tied to Changes in Brain Morphology in a Densely Sampled Male.

Circadian, infradian, and seasonal changes in steroid hormone secretion have been tied to changes in brain volume in several mammalian species. However, the relationship between circadian changes in steroid hormone production and rhythmic changes in brain morphology in humans is largely unknown. Here, we examined the relationship between diurnal fluctuations in steroid hormones and multiscale brain morphology in a precision imaging study of a male who completed 40 MRI and serological assessments at 7 A.M. and 8 P.M. over the course of a month, targeting hormone concentrations at their peak and nadir. Diurnal fluctuations in steroid hormones were tied to pronounced changes in global and regional brain morphology. From morning to evening, total brain volume, gray matter volume, and cortical thickness decreased, coincident with decreases in steroid hormone concentrations (testosterone, estradiol, and cortisol). In parallel, cerebrospinal fluid and ventricle size increased from A.M. to P.M. Global changes were driven by decreases within the occipital and parietal cortices. These findings highlight natural rhythms in brain morphology that keep time with the diurnal ebb and flow of steroid hormones.

Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running

To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and β-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17β-oestradiol, progesterone, P1NP and β-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17β-oestradiol concentrations (pg·ml−1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p = < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml−1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml−1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). β-CTX-1 concentrations (ng·ml−1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.

Exploring the Contribution of Traditional Medicinal Herbs in ManagingPolycystic Ovary Syndrome: A Comprehensive Review

: Polycystic ovary syndrome (PCOS) is a significant gynecological disorder that commonly affects women of reproductive age. Disturbances in the production and metabolism of androgens and estrogens mark the condition. Due to the rising occurrence of PCOS and its related physical and psychological issues, along with the role of sex hormone fluctuations in its development, the use of marketed drugs is effective in treating PCOS but is accompanied by negative consequences. Consequently, a significant number of individuals with PCOS are opting for natural remedies due to the positive therapeutic effects associated with natural medications and the constraints of allopathic treatments. This review aims to assess the impact of different herbs on alterations in sex hormone levels in the bloodstream and ovarian tissue. By conducting a comprehensive literature search utilizing databases such as PubMed, Google Scholar, and Crossref, we have gathered and analyzed pertinent information regarding the efficacy of herbal remedies in combating PCOS. Based on the available evidence, herbs consisting of phytoestrogens can potentially reduce insulin resistance, hyperandrogenism, and ovarian weight while facilitating ovulation. This review explores the importance of herbal remedies in addressing PCOS, elucidates their mechanisms of action, and examines the therapeutic uses of specific herbal medications to treat PCOS. Human studies on medicinal herbs for managing Polycystic Ovary Syndrome (PCOS) need extended durations for a comprehensive evaluation of both safety and efficacy, emphasizing the necessity for more long-term research. It is anticipated that this comprehensive review will serve as a valuable resource for researchers studying the effect of herbs on PCOS, providing them with valuable insights and information.

The Influence of Sex Steroid Hormone Fluctuations on Capsaicin-Induced Pain and TRPV1 Expression.

Sexual dimorphism among mammals includes variations in the pain threshold. These differences are influenced by hormonal fluctuations in females during the estrous and menstrual cycles of rodents and humans, respectively. These physiological conditions display various phases, including proestrus and diestrus in rodents and follicular and luteal phases in humans, distinctly characterized by varying estrogen levels. In this study, we evaluated the capsaicin responses in male and female mice at different estrous cycle phases, using two murine acute pain models. Our findings indicate that the capsaicin-induced pain threshold was lower in the proestrus phase than in the other three phases in both pain assays. We also found that male mice exhibited a higher pain threshold than females in the proestrus phase, although it was similar to females in the other cycle phases. We also assessed the mRNA and protein levels of TRPV1 in the dorsal root and trigeminal ganglia of mice. Our results showed higher TRPV1 protein levels during proestrus compared to diestrus and male mice. Unexpectedly, we observed that the diestrus phase was associated with higher TRPV1 mRNA levels than those in both proestrus and male mice. These results underscore the hormonal influence on TRPV1 expression regulation and highlight the role of sex steroids in capsaicin-induced pain.

Photo-Cross-linked Gelatin Methacryloyl Hydrogels Enable the Growth of Primary Human Endometrial Stromal Cells and Epithelial Gland Organoids.

In vitro three-dimensional (3D) models are better able to replicate the complexity of real organs and tissues than 2D monolayer models. The human endometrium, the inner lining of the uterus, undergoes complex changes during the menstrual cycle and pregnancy. These changes occur in response to steroid hormone fluctuations and elicit crosstalk between the epithelial and stromal cell compartments, and dysregulations are associated with a variety of pregnancy disorders. Despite the importance of the endometrium in embryo implantation and pregnancy establishment, there is a lack of in vitro models that recapitulate tissue structure and function and as such a growing demand for extracellular matrix hydrogels that can support 3D cell culture. To be physiologically relevant, an in vitro model requires mechanical and biochemical cues that mimic those of the ECM found in the native tissue. We report a semisynthetic gelatin methacryloyl (GelMA) hydrogel that combines the bioactive properties of natural hydrogels with the tunability and reproducibility of synthetic materials. We then describe a simple protocol whereby cells can quickly be encapsulated in GelMA hydrogels. We investigate the suitability of GelMA hydrogel to support the development of an endometrial model by culturing the main endometrial cell types: stromal cells and epithelial cells. We also demonstrate how the mechanical and biochemical properties of GelMA hydrogels can be tailored to support the growth and maintenance of epithelial gland organoids that emerge upon 3D culturing of primary endometrial epithelial progenitor cells in a defined chemical medium. We furthermore demonstrate the ability of GelMA hydrogels to support the viability of stromal cells and their function measured by monitoring decidualization in response to steroid hormones. This study describes the first steps toward the development of a hydrogel matrix-based model that recapitulates the structure and function of the native endometrium and could support applications in understanding reproductive failure.

Uncovering ovarian reserve: Insights into hormones, lipids, and essential metals

: Polycystic Ovary Syndrome (PCOS) is an endocrine disorder prevalent in women of reproductive age group. The intricate nature of PCOS development is highlighted by fluctuations in various sex hormones, such as luteinizing hormone(LH), follicle-stimulating hormone and prolactin. This study aims to assess the lipid profile levels, vital metals and sex hormones in the serum of patients with PCOS and contrast these findings with normal controls.The study analyzed health metrics between 57 women with PCOS and 57 normal controls. The lipid profile was assessed using Beckman Coulter AU480. Sex hormones were estimated using Roche Diagnostics Cobas 6000. Inductively coupled plasma mass spectrometry (ICPMS) was used to measure the essential trace metals, including magnesium (Mg), copper (Cu) Selenium (Se) and zinc (Zn).: The PCOS patients exhibited significantly elevated levels of LH (9.52 vs 3.48, p&amp;#60;0.0001), FSH (9.91 vs. 6.12, p&amp;#60;0.0001) and prolactin (24.71 vs. 16.41, p=0.03) mIU/ml. The correlation study showed a significant positive correlation between AMH and Se levels (R=0.27, p=0.045) and between LH and HDL (R=0.76, p=0.030).: In patients with PCOS, LH, FSH, and prolactin levels were found to be increased. A correlation was observed between Se and AMH, and a relationship was noted between LH and HDL. Selenium appears to have a significant influence on the ovarian reserve.

Diurnal Fluctuations in Steroid Hormones Tied to Variation in Intrinsic Functional Connectivity in a Densely Sampled Male.

Most of mammalian physiology is under the control of biological rhythms, including the endocrine system with time-varying hormone secretion. Precision neuroimaging studies provide unique insights into how the endocrine system dynamically regulates aspects of the human brain. Recently, we established estrogen's ability to drive widespread patterns of connectivity and enhance the global efficiency of large-scale brain networks in a woman sampled every 24 h across 30 consecutive days, capturing a complete menstrual cycle. Steroid hormone production also follows a pronounced sinusoidal pattern, with a peak in testosterone between 6 and 7 A.M. and nadir between 7 and 8 P.M. To capture the brain's response to diurnal changes in hormone production, we carried out a companion precision imaging study of a healthy adult man who completed MRI and venipuncture every 12-24 h across 30 consecutive days. Results confirmed robust diurnal fluctuations in testosterone, 17β-estradiol-the primary form of estrogen-and cortisol. Standardized regression analyses revealed widespread associations between testosterone, estradiol, and cortisol concentrations and whole-brain patterns of coherence. In particular, functional connectivity in the Dorsal Attention Network was coupled with diurnally fluctuating hormones. Further, comparing dense-sampling datasets between a man and a naturally cycling woman revealed that fluctuations in sex hormones are tied to patterns of whole-brain coherence in both sexes and to a heightened degree in the male. Together, these findings enhance our understanding of steroid hormones as rapid neuromodulators and provide evidence that diurnal changes in steroid hormones are associated with patterns of whole-brain functional connectivity.

Impact of Physiological Fluctuations of Sex Hormones During the Menstrual Cycle on Glucose Metabolism and the Gut Microbiota.

Diabetes mellitus is one of the most prevalent chronic diseases. Previous studies have shown differences in glucose metabolism between males and females. Moreover, difficulties in medication adherence have been reported in females with type 2 diabetes. These observations are believed to be caused by fluctuations in sex hormone concentrations during the menstrual cycle. Furthermore, gut microbiota is linked to female host metabolism and sex hormone production. Understanding the interactions between fluctuating hormone concentrations during the menstrual cycle, gut microbiota, and glucose metabolism in humans is significant because of the increasing prevalence of diabetes and the consequent need to expand preventive efforts. A literature search was performed to determine and summarize the existing evidence, deduce future research needs to maintain female health, and investigate the relationship between the physiological menstrual cycle and glucose metabolism. Studies from 1967 to 2020 have already examined the relationship between variations during the menstrual cycle and glucose metabolism in healthy female subjects using an oral-glucose tolerance test or intravenous glucose tolerance test. However, the overall number of studies is rather small and the results are contradictory, as some studies detected differences in glucose concentrations depending on the different cycle phases, whereas others did not. Some studies reported lower glucose levels in the follicular phase than in the luteal phase, whereas another study detected the opposite. Data on gut microbiota in relation to the menstrual cycle are limited. Conflicting results exist when examining the effect of hormonal contraceptives on the gut microbiota and changes in the course of the menstrual cycle. The results indicate that the menstrual cycle, especially fluctuating sex hormones, might impact the gut microbiota composition.The menstrual cycle may affect the gut microbiota composition and glucose metabolism. These results indicate that glucose tolerance may be the greatest in the follicular phase; however, further well-conducted studies are needed to support this assumption.

Whole-brain dynamics across the menstrual cycle: the role of hormonal fluctuations and age in healthy women

Recent neuroimaging research suggests that female sex hormone fluctuations modulate brain activity. Nevertheless, how brain network dynamics change across the female menstrual cycle remains largely unknown. Here, we investigated the dynamical complexity underlying three menstrual cycle phases (i.e., early follicular, pre-ovulatory, and mid-luteal) in 60 healthy naturally-cycling women scanned using resting-state fMRI. Our results revealed that the pre-ovulatory phase exhibited the highest dynamical complexity (variability over time) across the whole-brain functional network compared to the early follicular and mid-luteal phases, while the early follicular showed the lowest. Furthermore, we found that large-scale resting-state networks reconfigure along menstrual cycle phases. Multilevel mixed-effects models revealed age-related changes in the whole-brain, control, and dorsal attention networks, while estradiol and progesterone influenced the whole-brain, DMN, limbic, dorsal attention, somatomotor, and subcortical networks. Overall, these findings evidence that age and ovarian hormones modulate brain network dynamics along the menstrual cycle.

Cortical morphology variations during the menstrual cycle in individuals with and without premenstrual dysphoric disorder

BackgroundPremenstrual dysphoric disorder (PMDD) is hypothesized to stem from maladaptive neural sensitivity to ovarian steroid hormone fluctuations. Recently, we found thinner cortices in individuals with PMDD, compared to healthy controls, during the symptomatic phase. Here, we aimed at investigating whether such differences illustrate state-like characteristics specific to the symptomatic phase, or trait-like features defining PMDD. MethodsPatients and controls were scanned using structural magnetic resonance imaging during the mid-follicular and late-luteal phase of the menstrual cycle. Group-by-phase interaction effects on cortical architecture metrics (cortical thickness, gyrification index, cortical complexity, and sulcal depth) were assessed using surface-based morphometry. ResultsIndependently of menstrual cycle phase, a main effect of diagnostic group on surface metrics was found, primarily illustrating thinner cortices (0.3 < Cohen's d > 1.1) and lower gyrification indices (0.4 < Cohen's d > 1.0) in patients compared to controls. Furthermore, menstrual cycle-specific effects were detected across all participants, depicting a decrease in cortical thickness (0.4 < Cohen's d > 1.7) and region-dependent changes in cortical folding metrics (0.4 < Cohen's d > 2.2) from the mid-follicular to the late luteal phase. LimitationsSmall effects (d = 0.3) require a larger sample size to be accurately characterized. ConclusionsThese findings provide initial evidence of trait-like cortical characteristics of the brain of individuals with premenstrual dysphoric disorder, together with indications of menstrual cycle-related variations in cortical architecture in patients and controls. Further investigations exploring whether these differences constitute stable vulnerability markers or develop over the years may help understand PMDD etiology.

Monitoring of sprint and change of direction velocity, vertical jump height, and repeated sprint ability in sub-elite female football players throughout their menstrual cycle

ABSTRACT Aims The aim of this study was to investigate the associations between the early follicular (EF, i.e., menstruation), late follicular (LF), and middle luteal (ML) phases of the menstrual cycle and different factors that may influence football performance. Methods To this end, 11 eumenorrheic sub-elite female football players underwent field tests to assess sprint speed, lower extremity power, repeated sprint ability, velocity on change of direction, and technical skills at each cycle phase. Results Performance during the 15-m change of direction ability test, 15-m ball dribbling test, squat jump height, total sprint time [sum of 7 sprints] and decrement score [(mean sprint time/best sprint time × 100) − 100], maximum and mean heart rate, and perceived exertion did not significantly differ among menstrual cycle phases. Conversely, the linear sprint velocity over 10, 20, 30-m distances was decreased in EF vs LF (10-, 20- and 30-m) and in ML vs LF (10- and 20-m) (p < 0.05). The 40-m sprint velocity did not change in the different menstrual cycle phases. Conclusion Overall, our study suggests that sex hormone fluctuations during the menstrual cycle are not associated with vertical jump, velocity on change of direction, and repeated sprint ability, but may influence linear sprint velocity over short distances (10, 20, and 30 m).

Unveiling the Influence of the Menstrual Cycle on Mental Rotation Abilities: A Comparative Analysis of Three-Dimensional vs. Two-Dimensional Tasks

The activational effects of sex hormones on spatial ability have been well documented. It has been suggested that these effects might be related to hormonally induced changes in interhemispheric communication. In this EEG study, we opted to explore menstrual cycle-related changes in the efficacy of solving mental rotation tasks and laterality indices while participants were engaged with the tasks. We compared 2D and 3D mental rotation tasks, as they differ both psychometrically and in terms of lateralization. A group (n = 39) of healthy young women was tested twice, once during the mid-luteal (high estrogen and progesterone) and once during the early follicular (low levels of sex hormones) phase of menstrual cycle. The differences in power within the same frequency band on homologous sites of the left and right hemispheres were then calculated. Participants were faster, more accurate, and showed higher laterality scores when solving 3D mental rotation tasks in the early follicular phase compared to the mid-luteal phase. This indicates a higher lateralization of this specific spatial function when the levels of sex hormones are low. However, for 2D mental rotation tasks, participants showed neither shifts in efficacy nor in hemispheric laterality as a function of the menstrual cycle. This pattern of results provides further support for the notion that fluctuations in sex hormones affect laterality, and consequently, the expression of lateralized cognitive abilities.

Weight gain during menopause: physiology and practical implications

Fluctuations in sex hormones at different stages of reproductive life, such as the menopausal transition, have been suggested as players in weight regulation. Indeed, the transition from a predominantly estrogenic state to an androgenic state characteristic of the menopausal transition contributes to changes in body composition with accumulation of fat and simultaneous loss of lean mass. However, whether these changes contribute to the weight gain remains debatable. Other physiological and psychosocial factors come into play. It is therefore important to offer individualized support with the objective to minimize the risk of weight gain and associated complications.

THE INFLUENCE OF MENSTRUATION ON TRAINING SCHEDULES IN WELL-TRAINED AND ELITE FEMALE MOUNTAIN BIKE, ROAD AND CYCLOCROSS ATHLETES

Female physiology is unique and driven by fluctuations in sex hormones that regulate the menstrual cycle. These hormones present myriad mechanisms that may influence physiological systems, potentially implicating exercise performance. However, research exploring the MC in athletes is limited. This study investigated if training status (well-trained/elite) influenced MC-related symptoms, training schedules, sleep quality, arousal, and alertness of elite and well-trained female mountain bike, road, and cyclocross athletes. Fifteen well-trained (n= 7) and elite (n= 8) cyclists (age: 29 ± 7yrs, height: 1.7 ± 0.1m, body mass: 61.9 ± 7.7kg) tracked their MC symptoms, basal body temperature, body mass, sleep, arousal, and alertness measures daily for three months. The MC was split into two phases, follicular and luteal, and participants were provided ovulation kits to identify the phases. The most reported symptoms were fatigue, bloating, abdominal pain, and cramping. Athletes’ BBT was significantly greater (p0.05) in body mass, sleep duration and quality, alertness and arousal were observed between well-trained and elite athletes. Further, no significant differences between statuses for any training variables, average or maximum heart rate, training load (bTRIMP), average or maximum speed, and rate of perceived exertion were observed. The MC did not influence physiological responses and training variables in well-trained and elite mountain bike, road, and cyclocross female athletes. Nevertheless, individual fluctuations were present, and it is recommended that athletes monitor their own MC to optimize training and ultimately performance.

Female Athletes and the Menstrual Cycle in Team Sports: Current State of Play and Considerations for Future Research.

Over the past ten years there has been a dramatic rise in female sport participation and accompanying female professional national leagues across multiple sports, yet research has not followed suit. Although there are known variations between female and male physiology, training protocols in female sport are predominantly underpinned by research undertaken in male athletes. The hormonal variability experienced by women across the menstrual cycle, as well as the menstrual cycle variability between women, may contribute to the complexity of conducting rigorous physiological studies, leading to a paucity of robust sports-specific research that can be confidently applied to female athletes. Moreover, barriers exist in female sport that potentially limit the ability to conduct research, including the lack of full-time programs and limited resources. Recently, there has been increased interest in the potential effects of fluctuations in the female sex hormones, progesterone and oestrogen, on sport performance across different phases of the menstrual cycle. However, current research evaluating the menstrual cycle and physical performance (such as strength, speed, aerobic fitness, and athletes' perception of their performance) have shown inconsistent results. Additionally, methodological design across studies has shown little consistency, making it difficult to draw firm conclusions, which potentially prevents female athletes optimising their physical and sporting performance. It further impacts coaches and sports science researchers in their ability to provide appropriate training recommendations and educational opportunities. It is important to progress in female athlete research with an understanding of how the unique physiology of female athletes may influence their ability to physically perform in their respective sport, which requires representation in sports science research. This paper will provide an overview on current evidence and limitations within menstrual cycle research and provide considerations and directions for future research in this space within team sports.