Determining menstrual phase in human biobehavioral research: A review with recommendations

The Menstrual Cycle as a Vital Sign: a comprehensive review

Some medical professional organizations have advocated for including the menstrual cycle as a vital sign in adolescence, but not in adulthood. However, documenting menstrual cycle patterns is not routine clinical or research practice. Vital signs are used to predict health outcomes, indicate needed treatment, and monitor a clinical course. They can help identify pathologies, affirm wellness, and are responsive to exposures. Here we review the scientific evidence showing how the menstrual cycle meets these criteria and should therefore be treated as a vital sign. Using key words and controlled vocabulary terms, we carried out multiple literature searches, prioritizing the inclusion of systematic reviews, meta-analyses, and clinical practice guidelines. This review describes how the menstrual cycle is a health indicator, can cyclically impact health conditions, and its associations with long-term post-menopausal health outcomes. We review exposures influencing the menstrual cycle, evidence underlying its use to optimize wellness, and available tools for documenting cycles. Supplementary materials include patient handouts on menstrual cycle tracking, and an index of related clinical practice guidelines and reviews by subject. The menstrual cycle is a vital sign from menarche through menopause, an underutilized but powerful tool for understanding gynecological and general health.

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.

Effects of the Menstrual Cycle Phase on Cortisol Responses to Maximum Exercise in Women With and Without Premenstrual Syndrome

Objectives

This study investigated the effects of the menstrual cycle phases on cortisol levels before and after a maximal incremental exercise test in women with and without premenstrual syndrome (PMS).

Methods

Nineteen healthy, active and eumenorrheic women completed five maximal incremental exercise tests; three of those were performed at specific phases of the menstrual cycle (i.e., menses, follicular, and luteal). The participants were allocated into two groups according to the presence of PMS (n = 11) or absence of PMS (NO-PMS, n = 8). Samples of blood were collected before and after each experimental test. A three-way ANOVA was conducted to compare the differences between menstrual cycle phases (i.e., menses, follicular, and luteal), time (before and after) and groups (PMS and NO-PMS).

Results

The results demonstrated an alteration of cortisol across the menstrual cycle, with cortisol levels significantly (p < 0.05) higher during the follicular phase (mean = 11.0 μg/dL, CI95% = 9.1, 12.9) compared to the luteal phase (mean = 8.6 μg/dL, CI95% = 7.2, 10.4) in the PMS and NO-PMS groups. There was no difference (p > 0.05) in cortisol levels for groups or time.

Conclusions

This study observed significant cortisol fluctuations across the menstrual cycle phases in women with and without PMS. Future studies should consider alternative maximal incremental test protocols and incorporate a more comprehensive hormonal profile to provide a deeper physiological understanding of this population.

Best practices for including sex as a variable in appetite research

Despite increasing recognition that sex is a critical variable in appetite research, many studies fail to include participants of both sexes, fail to consider reproductive physiology in participant selection, or include both sexes but fail to test for sex differences in outcomes. To help remedy this situation, this article seeks to engender enthusiasm for including sex as a variable in appetite research. We first illustrate some sex differences in healthy and disordered eating, including both male-female differences and differences across the menstrual cycle. We next provide methodological guidance for studies involving male and female participants around puberty, during reproductive adulthood, and during reproductive senescence. Studies in children ≥5 y of age should consider adrenarche and gonadarche. Appetite studies in girls and women following menarche and similarly aged males should consider the influences of sex-specific aspects the hypothalamic-pituitary-gonadal (HPG) axis function. The cyclicity of HPG function (i.e., the menstrual cycle) in girls and women presents the challenge of identifying of menstrual-cycle subphases, which are highly variable within and between individuals. Reproductive senescence refers to changes in HPG axis function that occur in both men and women beginning in mid-life. Current best practices involve consideration of hormone-assay methodology, experimental design, and statistical analyses. On the horizon are options based on wearable-sensors and nanotechnology. Well informed consideration of sex as a variable will accelerate progress in appetite research by increasing rigor, replicability, and relevance.

Investigating the Role of Exercise Pattern in Acute Cardiovagal Recovery

PURPOSE

Research on intermittent training has mainly focused on the effects of exercise intensity while overlooking the specific effect of the modulations associated with alternating exercise and recovery. This study investigated how the frequency of modulations during moderate-intensity exercise affects postexercise vagal reactivation.

METHODS

Healthy, active females and males 18-39 yr old were recruited for the study. Participants completed three treadmill running sessions on separate days. Each moderate-intensity session accumulated 30 min at 90% of the intensity associated with the second ventilatory threshold and was performed as either high-frequency intermittent (HiFi; 15 × [2 min + 2 min recovery]), low-frequency intermittent (LoFi; 5 × [6 min + 2 min recovery]), or moderate-intensity continuous training (MICT; 1 × 30 min). Heart rate recovery (HR rec ) at 1 min and heart rate variability recovery (HRV rec ; lnRMSSD) were assessed in response to submaximal constant-speed tests performed before (CST1) and after (CST2) each of the exercise sessions. HR rec , HRV rec , blood lactate (BLa), and blood pressure were also collected during the exercise sessions.

RESULTS

Twenty-one individuals (8 females, 13 males) participated in the study. HR rec from CST2 was faster in HiFi versus MICT ( P < 0.001), whereas HRV rec post-CST2 was higher after HiFi versus both LoFi ( P = 0.024) and MICT ( P < 0.001). BLa increased in all conditions ( P = 0.007) but remained lower during HiFi compared with LoFi and MICT (both P < 0.001). Diastolic blood pressure did not change during exercise with HiFi ( P = 0.939) but decreased during LoFi ( P = 0.006) and MICT ( P = 0.008).

CONCLUSIONS

Exercise pattern influences the physiologic response to exercise. Higher frequencies of modulations can preserve vagal activity and expedite postexercise recovery, suggesting moderate-intensity intermittent exercise as a potential strategy to mitigate autonomic impact and acute physiological stress while maintaining total work performed.

Cardiac Autonomic and Affective Reactivity to Laboratory Stressors across the Menstrual Cycle: A Systematic Review

Fluctuations in steroid sex hormones are associated with altered cardiac autonomic and affective functioning across the female lifespan. The neuroendocrine pathways which modulate sex hormone changes during the menstrual cycle have reciprocal interactions with the autonomic nervous system, an integral system for self-regulation and stress response. Cardiac autonomic activity is often imbalanced among individuals with mental and physical health conditions. However, it is unclear whether variations in female-typical sex hormones across the menstrual cycle significantly alter cardiac autonomic and affective stress reactivity, which may underlie menstrual-related mood and psychosomatic symptoms. The present systematic review aims to address this gap by characterizing patterns of cardiac autonomic activity at baseline, and cardiac autonomic and affective reactivity to laboratory stress tasks across the menstrual cycle in reproductive-aged women. The review was preregistered (https://doi.org/10.17605/OSF.IO/B2Y5Q) and conducted in line with PRISMA guidelines. Twenty studies and 28 records were identified and discussed. The study found modest support for increased cardiac sympathetic activation at baseline and in response to stress, and greater affective reactivity within the luteal phase of the menstrual cycle. These results expand upon prior research demonstrating cardiac autonomic imbalance and affective vulnerability within the luteal phase to show that these patterns also influence stress reactivity. Additionally, the review aims to identify notable methodological limitations and gaps within this body of literature and suggests areas of future research to clarify the role of cardiac autonomic and affective processes in steroid sex hormone-related symptomatology.

Macular, choroidal and disc associations across women's reproductive life stages: a scoping review from menarche to post-menopause

Oestrogen and progesterone fluctuate cyclically in women throughout their adult lives. Although these hormones cross the blood-retinal barrier and bind to intraocular receptors, their effects remain unclear. We present the first review to date on associations between posterior pole structures-specifically the macula, choroid, and optic disc-and both the menstrual cycle and post-menopausal period, utilising multimodal imaging techniques in healthy adult non-pregnant women. We excluded studies on contraception and hormonal replacement therapy, focusing solely on physiological associations. Despite the comprehensive scope of our review, limited data and inconsistent reporting among studies prevented the establishment of meaningful trends. Across menstrual cycle phases, choroidal thickness (CHT) was the most consistently reported parameter, with thinning during the luteal phase compared to the follicular phase. Conversely, no significant differences were observed in macular or disc morphology across the cycle, likely reflecting a preserved structure despite potential fluctuations in blood flow and perfusion. Studies comparing pre- and post-menopausal associations, after adjusting for age or body mass index (BMI), failed to reveal meaningful trends, highlighting the difficulty in separating the effect of age from hormonal declines in older women. Understanding how hormonal cycles impact the posterior pole in women is crucial for addressing sex differences in various ocular pathologies. Research on female-specific factors is still sparse, and interestingly, the majority of affiliations in the reviewed articles did not originate from regions with the highest biomedical research funding and publication rates. We encourage further studies focusing on female-specific variables and provide recommendations for future designs.

Using a Composite Summary of Daily Sex Hormones to Gauge Time Until Menopause: A Focus on Pregnanediol Glucuronide (PDG)

CONTEXT

The timing of a woman's final menstrual period (FMP) in relation to her age is considered a valuable indicator of overall health, being associated with cardiovascular, bone health, reproductive, and general mortality outcomes.

OBJECTIVE

This work aimed to evaluate the relationship between hormones and the "time to FMP" when daily hormone trajectories are characterized by their 1) entropy, and 2) deviation from premenopausal/stable cycle patterns (representing a textbook "gold standard"; GS).

METHODS

As part of the Study of Women's Health Across the Nation, urinary luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogen conjugates (E1C), and pregnanediol glucuronide (PDG) were measured daily from a multiracial sample of 549 mid-life women for the duration of one menstrual cycle. Hormone trajectories were mapped onto a plane with axes representing Fuzzy entropy (FuzzEn) and the normalized dynamic time warping distance (DTW) from the GS.

RESULTS

Viewing FSH, E1C, PDG, and LH through this lens reveals that, contrary to existing wisdom, PDG stands out as a powerful predictor/descriptor of "time to FMP." Using cluster analyses to discretize PDG on the DTW/FuzzEn plane yields statistically different survival curves, and Cox proportional hazards analyses confirm that this separation persists in the presence of known covariates of FSH, antimüllerian hormone, age, body mass index, financial hardship, smoking status, and cycle length.

CONCLUSION

Since PDG is generally not considered a predictor/descriptor of ovarian aging, this work validates the DTW/FuzzEn analytical framework and introduces another metric/hormone to be used in FMP-related preventive care.

Retinal morphology across the menstrual cycle: insights from the UK Biobank

Oestradiol and progesterone levels are higher in menstruating women than men of the same age, and their receptors are present in their neurosensory retina and retinal pigment epithelium. However, the impact of this hormonal environment on retinal physiology in women remains unclear. Using self-reported menstrual cycle phases as a surrogate for fluctuating hormonal levels, we investigated associations with retinovascular indices on colour fundus photograph and retinal thickness in optical coherence tomography across regularly menstruating women in the UK Biobank. We found no differences in retinal thickness across the cycle; however, vessel density, arteriolar and venular, and fractal dimension were higher in the luteal phase than follicular. The calibre of the central retinal vessels did not differ. This study suggests that the menstrual cycle phase might be associated with retinal microvasculature density in non-invasive imaging. It raises awareness for this understudied area, providing insights into neuroscience fields and epidemiological studies.

Comparison of repeatability of subjective appetite sensations in men and women at different menstrual cycle phase

Introduction

Introduction: appetite can be measured through subjective sensations of appetite (SSA), which can be assessed by means of scales, the most relevant being the visual analog scales (VAS). Objective: to analyze the repeatability of VAS in men and women in follicular phase (FF) and luteal phase (LF) of the menstrual cycle Materials and methods: 34 men and women were included. VAS of subjective appetite sensations (SAS) were applied before and after standardized breakfast in two sessions. Results: women LP showed intra-class correlation coefficient (ICC) values greater than 0.5, and most of VAS in women FP and men showed ICC values greater than 0.7. The ICC of hunger and desire to eat were different between men and women LP. Comparisons of these ICC´s showed that only hunger and desire to eat were different between men and women. Conclusion: repeatability of VAS was similar between men and women in different stages of menstrual cycle. This is the first study to assess repeatability of VAS in women in LP and to objectively compare the repeatability of VAS to evaluate SAS.

The influence of ovarian hormones on the putative mechanisms that promote female nicotine use

Nicotine use is driven by pleasurable effects, but following chronic exposure, nicotine use becomes largely driven by the desire need to avoid withdrawal symptoms. Current cessation strategies focusing on alleviating withdrawal, but current cessation interventions are less effective for women than men. Also, hormone fluctuations across the menstrual cycle appear to impact use patterns, withdrawal severity, and treatment efficacy. This raises important questions regarding optimal quit dates and the application of hormone interventions to alleviate withdrawal in women. This review surveys the existing literature assessing the impact of ovarian hormones on nicotine withdrawal severity. This is an important issue because women seeking cessation treatments may be using hormone-based contraceptives or hormone replacement post-menopause. Hormone interventions may also offer a novel treatment avenue that is more effective than current cessation approaches. Future work in this area is important for reducing health disparities produced by excessive nicotine use in women.

Probing corporeal awareness in women through virtual reality induction of embreathment illusion

We capitalized on the respiratory bodily illusion that we discovered in a previous study and called 'Embreathment' where we showed that breathing modulates corporeal awareness in men. Despite the relevance of the issue, no such studies are available in women. To bridge this gap, we tested whether the synchronization of avatar-participant respiration patterns influenced females' bodily awareness. We collected cardiac and respiratory interoceptive measures, administered body (dis)satisfaction questionnaires, and tracked participants' menstrual cycles via a mobile app. Our approach allowed us to characterize the 'Embreathment' illusion in women, and explore the relationships between menstrual cycle, interoception and body image. We found that breathing was as crucial as visual appearance in eliciting feelings of ownership and held greater significance than any other cue with respect to body agency in both women and men. Moreover, a positive correlation between menstrual cycle days and body image concerns, and a negative correlation between interoceptive sensibility and body dissatisfaction were found, confirming that women's body dissatisfaction arises during the last days of menstrual cycle and is associated with interoception. These findings have potential implications for corporeal awareness alterations in clinical conditions like eating disorders and schizophrenia.

The role of neurosteroids in posttraumatic stress disorder and alcohol use disorder: A review of 10 years of clinical literature and treatment implications

Rates of alcohol use disorder (AUD) are increasing in men and women and there are high rates of concurrent posttraumatic stress disorder (PTSD) and AUD. AUD and PTSD synergistically increase symptomatology and negatively affect treatment outcomes; however, there are very limited pharmacological treatments for PTSD/AUD. Neurosteroids have been implicated in the underlying neurobiological mechanisms of both PTSD and AUD and may be a target for treatment development. This review details the past ten years of research on pregnenolone, progesterone, allopregnanolone, pregnanolone, estradiol, testosterone and dehydroepiandrosterone/dehydroepiandrosterone-sulfate (DHEA/DHEA-S) in the context of PTSD and AUD, including examination of trauma/alcohol-related variables, such as stress-reactivity. Emerging evidence that exogenous pregnenolone, progesterone, and allopregnanolone may be promising, novel interventions is also discussed. Specific emphasis is placed on examining the application of sex as a biological variable in this body of literature, given that women are more susceptible to both PTSD diagnoses and stress-related alcohol consumption.

Menstrual Phase Identification Questionnaire (MPIQ): Development and validation of a cross-sectional survey to identify follicular and luteal phases

Evidence continues to accumulate on the influence of the menstrual phase on several biobehavioral outcomes (e.g., substance misuse). Expansion of this knowledge is limited due to the burdensomeness of accurate menstrual phase assessment. Thus, we sought to create and validate a questionnaire that can be used as a stand-alone item within low-resource settings and numerous study designs (e.g., cross-sectional) to accurately identify both the follicular phase (FP) and the luteal phase (LP). Participants completed the self-administered four-item Menstrual Phase Identification Questionnaire (MPIQ) in two recently completed clinical trials. We assessed the accuracy of two MPIQ scoring criteria (less restrictive and more restrictive), as compared to self-report of onset of menses alone, with progesterone confirmation via dried blood spots. Participants (n = 59) were, on average, 33.7 (standard deviation [SD]: ± 4.3) years old and provided a total of 83 responses. Assessing FP and LP using the self-reported onset of menses alone classified 65.1% of the responses with an overall phase identification accuracy of 60.2%. While the more restrictive MPIQ scoring classified 100% of the responses, it yielded a similar accuracy (68.4%). In contrast, the less restrictive MPIQ scoring classified 100% of the responses and also significantly improved phase identification accuracy to 92.1% (p < .001). The MPIQ, as a stand-alone item, allows all cross-sectional responses to be classified with a high level of accuracy. This low-burden questionnaire can be used alone to identify FP and LP in studies that may be otherwise limited by study design, finances, and/or participant burden. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Recommendations for Women in Mountain Sports and Hypoxia Training/Conditioning

The (patho-)physiological responses to hypoxia are highly heterogeneous between individuals. In this review, we focused on the roles of sex differences, which emerge as important factors in the regulation of the body's reaction to hypoxia. Several aspects should be considered for future research on hypoxia-related sex differences, particularly altitude training and clinical applications of hypoxia, as these will affect the selection of the optimal dose regarding safety and efficiency. There are several implications, but there are no practical recommendations if/how women should behave differently from men to optimise the benefits or minimise the risks of these hypoxia-related practices. Here, we evaluate the scarce scientific evidence of distinct (patho)physiological responses and adaptations to high altitude/hypoxia, biomechanical/anatomical differences in uphill/downhill locomotion, which is highly relevant for exercising in mountainous environments, and potentially differential effects of altitude training in women. Based on these factors, we derive sex-specific recommendations for mountain sports and intermittent hypoxia conditioning: (1) Although higher vulnerabilities of women to acute mountain sickness have not been unambiguously shown, sex-dependent physiological reactions to hypoxia may contribute to an increased acute mountain sickness vulnerability in some women. Adequate acclimatisation, slow ascent speed and/or preventive medication (e.g. acetazolamide) are solutions. (2) Targeted training of the respiratory musculature could be a valuable preparation for altitude training in women. (3) Sex hormones influence hypoxia responses and hormonal-cycle and/or menstrual-cycle phases therefore may be factors in acclimatisation to altitude and efficiency of altitude training. As many of the recommendations or observations of the present work remain partly speculative, we join previous calls for further quality research on female athletes in sports to be extended to the field of altitude and hypoxia.

White matter microstructure in transmasculine and cisgender adolescents: A multiparametric and multivariate study

Adolescence is a sensitive developmental period for neural sex/gender differentiation. The present study used multiparametric mapping to better characterize adolescent white matter (WM) microstructure. WM microstructure was investigated using diffusion tensor indices (fractional anisotropy; mean, radial, and axial diffusivity [AD]) and quantitative T1 relaxometry (T1) in hormone therapy naïve adolescent cisgender girls, cisgender boys, and transgender boys (i.e., assigned female at birth and diagnosed with gender dysphoria). Diffusion indices were first analyzed for group differences using tract-based spatial statistics, which revealed a group difference in AD. Thus, two multiparametric and multivariate analyses assessed AD in conjunction with T1 relaxation time, and with respect to developmental proxy variables (i.e., age, serum estradiol, pubertal development, sexual attraction) thought to be relevant to adolescent brain development. The multivariate analyses showed a shared pattern between AD and T1 such that higher AD was associated with longer T1, and AD and T1 strongly related to all five developmental variables in cisgender boys (10 significant correlations, r range: 0.21-0.73). There were fewer significant correlations between the brain and developmental variables in cisgender girls (three correlations, r range: -0.54-0.54) and transgender boys (two correlations, r range: -0.59-0.77). Specifically, AD related to direction of sexual attraction (i.e., gynephilia, androphilia) in all groups, and T1 related to estradiol inversely in cisgender boys compared with transgender boys. These brain patterns may be indicative of less myelination and tissue density in cisgender boys, which corroborates other reports of protracted WM development in cisgender boys. Further, these findings highlight the importance of considering developmental trajectory when assessing the subtleties of neural structure associated with variations in sex, gender, and sexual attraction.

Greater sensitivity of the circadian system of women to bright light, but not dim-to-moderate light

Women typically sleep and wake earlier than men and have been shown to have earlier circadian timing relative to the light/dark cycle that synchronizes the clock. A potential mechanism for earlier timing in women is an altered response of the circadian system to evening light. We characterized individual-level dose-response curves for light-induced melatonin suppression using a within-subjects protocol. Fifty-six participants (29 women, 27 men; aged 18-30 years) were exposed to a range of light illuminances (10, 30, 50, 100, 200, 400, and 2000 lux) using melatonin suppression relative to a dim control (<1 lux) as a marker of light sensitivity. Women were free from hormonal contraception. To examine the potential influence of sex hormones, estradiol and progesterone was examined in women and testosterone was examined in a subset of men. Menstrual phase was monitored using self-reports and estradiol and progesterone levels. Women exhibited significantly greater melatonin suppression than men under the 400-lux and 2000-lux conditions, but not under lower light conditions (10-200 lux). Light sensitivity did not differ by menstrual phase, nor was it associated with levels of estradiol, progesterone, or testosterone, suggesting the sex differences in light sensitivity were not acutely driven by circulating levels of sex hormones. These results suggest that sex differences in circadian timing are not due to differences in the response to dim/moderate light exposures typically experienced in the evening. The finding of increased bright light sensitivity in women suggests that sex differences in circadian timing could plausibly instead be driven by a greater sensitivity to phase-advancing effects of bright morning light.

Potential factors contributing to observed sex differences in virtual-reality-induced sickness

Virtual reality (VR) technology has been widely adopted for several professional and recreational applications. Despite rapid innovation in hardware and software, one of the long prevailing issues for end users of VR is the experience of VR sickness. Females experience stronger VR sickness compared to males, and previous research has linked susceptibility to VR sickness to the menstrual cycle (Munafo et al., Exp Brain Res 235(3):889-901). Here we investigated the female versus male experience in VR sickness while playing an immersive VR game, comparing days of the menstrual cycle when hormones peak: day 15 (ovulation-peak estrogen) and day 22 (mid-luteal phase-peak progesterone). We found that immersion duration was greater in the second session than the first, and discomfort was lessened, suggesting a powerful adaptation with repeated exposure. Due to the estrogen levels changing along with the exposure, there was no clear independent impact of that; note, though, that there was a significant difference between self-report and physiological measures implying that GSR is potentially an unreliable measure of motion sickness. Although prior work found a delay over 2 days between session would not allow adaptation and habituation to reduce VR sickness susceptibility, we found that a week delay has potential success.

The Influence of Menstrual Cycle Phases on Maximal Strength Performance in Healthy Female Adults: A Systematic Review with Meta-Analysis

Maximal strength is a significant factor in achieving peak performance and injury prevention in athletes. In individualization strategies for the efficient development of athletes, it is necessary to consider the respective components separately. The purpose of this study was to systematically examine the effects of the different cycle phases on isometric, isokinetic, and dynamic maximum strength. A systematic literature review was conducted; databases were searched from January 1960 to September 2023. The included studies focused on the expression of maximal strength in the earlier follicular phase as well as at least one comparative phase. Of the initial 707 articles identified, 22 met the selection criteria and were included. The studies considered a total of 433 subjects. Our results revealed medium effects (weighted mean standardized mean difference (SMD) = 0.60; seven studies) for isometric maximal strength in favor of the late follicular phase, small effects (weighted mean SMD = 0.39; five studies) for isokinetic maximal strength in favor of the ovulation phase, and small effects (weighted mean SMD = 0.14; three studies) for dynamic maximal strength in favor of the late follicular phase. The results indicate that the early follicular phase is unfavorable for all strength classes. Peak performance in isometric strength is seen in the late follicular phase, whereas isokinetic strength peaks during ovulation. Dynamic strength is optimal in the late follicular phase.

Alterations of postural control across the menstrual cycle - A systematic review

BACKGROUND

Postural control is a vital component of injury prevention and prediction and plays a critical role in sports performance. Its relationship with the phases of the menstrual cycle (MC) is not yet fully understood and requires further investigation.

RESEARCH QUESTION

Does postural control alter between high hormone and low hormone phases of the MC?

METHODS

Five electronic databases were searched by two reviewers between 30th November and 2nd December 2022. Included were studies that investigated the effects of the MC on static and dynamic postural control in naturally cycling (NC) women by comparing the early follicular phase (EFP) with at least one high hormone phase of the MC. Two reviewers conducted the literature search, selection of eligible studies, data extraction, methodological quality assessment utilizing a modified Downs and Black Checklist, GRADE guidelines and SIGN grading, and synthesis of results.

RESULTS

Nine studies examined the effects of the MC on static (n = 7), dynamic (n = 1), or both forms of postural control (n = 1) in 148 NC women. Included studies were of very low to moderate quality. Level of evidence was either 2 + (n = 1) or 2- (n = 8). Limited evidence of five very low-quality studies indicated decreased static postural control during the ovulatory phase of the MC, compared to the EFP. The decrements were present in balance tasks that altered sensory input of at least two sensory systems of postural control.

SIGNIFICANCE

This systematic review is the first compiling evidence on the effect of the MC on postural control. Evidence that the MC influences postural control is unclear. However, a trend towards decrements in postural control form EFP to OP was observed in balance tasks that eliminated or altered sensory input. Hence, compensatory strategies might be less effective during the OP.

Isometric and isokinetic strength of lower-limb muscles in female athletes during different phases of menstrual cycle: a causal-comparative study

BACKGROUND

Muscle strength is affected by different stages of the menstrual cycle in women. Since the strength of the lower limb muscles plays a significant role in the occurrence of anterior cruciate ligament injury, it seems necessary to study the strength of the lower limb muscles at different stages of this cycle to take preventive measures. Therefore, this study aimed to compare the isometric and isokinetic strength of lower limb muscles in female athletes at different menstrual cycle stages.

METHODS

The present study is of a causal-comparative type. Thirty-seven female athletes in anterior cruciate ligament injury high-risk disciplines participated in this study. Isometric and isokinetic knee extensors and flexors muscle strength status, including the traditional hamstrings/quadriceps (H/Q) ratios, were recorded at different stages of the menstrual cycle (follicular, ovulatory, luteal) by Biodex isokinetic dynamometry system 4. Then, the obtained results were analyzed by repeated measure analysis of variance.

RESULTS

Analysis of variance with repeated measures showed isokinetic and isometric strength in the knee flexor and extensor muscles at an angular velocity of 60˚/s in the ovulatory phase are higher than the follicular and luteal ones. The strength of the muscles declined during the follicular and luteal phases (p ≤ 0.05).

CONCLUSIONS

Due to the negative effect of the follicular and luteal stages of the menstrual cycle on the strength of the flexor and extensor muscles of the knee, the risk of anterior cruciate ligament injury may increase during this period. Therefore, it is recommended that all female coaches and athletes take preventive measures during this period.

Altered response to Toll-like receptor 4 activation in fibromyalgia: A low-dose, human experimental endotoxemia pilot study

In this pilot study, a human intravenous injection of low-dose endotoxin (lipopolysaccharide, LPS) model was used to test if fibromyalgia is associated with altered immune responses to Toll-like receptor 4 (TLR4) activation. Eight women with moderately-severe fibromyalgia and eight healthy women were administered LPS at 0.1 ng/kg in session one and 0.4 ng/kg in session two. Blood draws were collected hourly to characterize the immune response. The primary analytes of interest, leptin and fractalkine, were assayed via commercial radioimmunoassay and enzyme-linked immunosorbent assay kits, respectively. Exploratory analyses were performed on 20 secreted cytokine assays by multiplex cytokine panels, collected hourly. Exploratory analyses were also performed on testosterone, estrogen, and cortisol levels, collected hourly. Additionally, standard clinical complete blood counts with differential (CBC-D) were collected before LPS administration and at the end of the session. The fibromyalgia group demonstrated enhanced leptin and suppressed fractalkine responses to LPS administration. In the exploratory analyses, the fibromyalgia group showed a lower release of IFN-γ, CXCL10, IL-17A, and IL-12 and higher release of IL-15, TARC, MDC, and eotaxin than the healthy group. The results of this study suggest that fibromyalgia may involve an altered immune response to TLR4 activation.

Methodological approach for an integrated female-specific study of anxiety and smoking comorbidity

Two primary ovarian hormones that fluctuate across the female menstrual cycle-estradiol and progesterone-have been independently linked in separate literatures to nicotine reinforcement and anxiety psychopathology. We identify existing methodological limitations in these literatures, describe an example protocol that was developed to address such limitations, highlight case examples, and offer insights on the resulting advantages and challenges. This protocol was an observational, prospective, within-subjects study of female cigarette smokers who were followed over the course of a complete menstrual cycle. Non-treatment seeking, female cigarette smokers (N = 50), between the ages of 18-40 who have a normal menstrual cycle (25-35 days in length) were recruited from the community. Females with anxiety or mood psychopathology represented 38.0% of the sample. Salivary progesterone and estradiol were assessed each morning via at-home saliva collection methods. Self-reported within-day momentary ratings of anxiety and nicotine reinforcement were collected using ecological momentary assessment (EMA) via a mobile app. Protocol compliance was >85%. Within- and between-subjects heterogeneity was observed in the progesterone and estradiol, anxiety, and nicotine craving measures, especially in the context of anxiety psychopathology. We aimed to integrate the anxiety and nicotine dependence literatures and advance the empirical study of the role of ovarian hormones. This protocol reflects an intensive, yet feasible approach to collecting daily-level naturalistic data related to estradiol, progesterone, anxiety, and nicotine reinforcement.

Gastrointestinal functioning and menstrual cycle phase in emerging young adult women: a cross-sectional study

BACKGROUND

Women experience more severe gastrointestinal (GI) symptoms compared to men. The onset of puberty and the menstrual cycle may influence these differences. Additionally, health anxiety is an important construct that has been shown to play a role in increased symptomatology across many medical conditions. Using standardized clinical measures often employed to assess disorders of gut-brain interaction (DGBI) we aimed to identify differences of GI functioning across menstrual cycle phases and to evaluate the role of health anxiety in this relationship.

METHODS

Six hundred three participants completed a survey including functional GI assessment scales (PROMIS-GI®), an abdominal pain scale and map, and a health anxiety measure. They were grouped by menstrual cycle phases (Menses, Follicular, Early-Luteal, and Premenstrual) based on self-reported start date of most recent period. Multivariate analyses of covariance were conducted to identify differences between menstrual cycle phase and scores on the symptom scales. Heath anxiety was included as a covariate in all analyses.

RESULTS

No significant differences were found between menstrual cycle group and PROMIS-GI scores. Higher GI-symptom and pain levels were found as health anxiety increased. Pain in the hypogastric region of the abdomen was significantly higher during the Menses phase when compared to Early-Luteal and Premenstrual phases. A subset of participants with DGBI diagnoses demonstrated significantly higher GI-symptom severity on several PROMIS-GI scales when compared to matched controls who did not have those diagnoses. In addition, participants with DGBI diagnoses reported significantly greater pain across multiple abdominal regions than their non-diagnosed counterparts.

CONCLUSIONS

GI symptom levels as measured by the PROMIS-GI scales in otherwise healthy women were not dependent on menstrual cycle phase. Yet, the PROMIS-GI scales were sensitive to symptom differences in women with DGBI diagnoses. Overall, this study demonstrated that the PROMIS-GI measures are unlikely to be affected by gynecological functioning in healthy young women. We argue that the abdominal pain map is an essential addition to classification and diagnosis.

A Novel Tissue-Specific Insight into Sex Steroid Fluctuations Throughout the Murine Estrous Cycle

Serum sex steroid levels fluctuate throughout the reproductive cycle. However, the degree to which sex steroid tissue content mimics circulating content is unknown. Understanding the flux and physiological quantity of tissue steroid content is imperative for targeted hormonal therapy development. Utilizing a gold-standard ultrasensitive liquid chromatography-mass spectrometry (LC/MS) method we determined sex steroid (17β-estradiol [E2], testosterone, androstenedione, and progesterone) fluctuations in serum and in 15 tissues throughout the murine estrous cycle (proestrus, estrus, and diestrus I) and in ovariectomized (OVX) mice. We observed dynamic fluctuations in serum and tissue steroid content throughout the estrous cycle with proestrus generally presenting the highest content of E2, testosterone, and androstenedione, and lowest content of progesterone. In general, the trend in circulating steroid content between the stages of the estrous cycle was mimicked in tissue. However, the absolute amounts of steroid levels when normalized to tissue weight were found to be significantly different between the tissues with the serum steroid quantity often being significantly lower than the tissue quantity. Additionally, we found that OVX mice generally displayed a depletion of all steroids in the various tissues assessed, except in the adrenal glands which were determined to be the main site of peripheral E2 production after ovary removal. This investigation provides a comprehensive analysis of steroid content throughout the estrous cycle in a multitude of tissues and serum. We believe this information will help serve as the basis for the development of physiologically relevant, tissue-specific hormonal therapies.

The effects of sex hormones during the menstrual cycle on knee kinematics

The effects of the menstrual cycle and sex hormones on knee kinematics remain unclear. The purpose of the study was to investigate the effects of the menstrual cycle and serum sex hormone concentrations on knee kinematic parameters of the 90°cutting in female college soccer athletes. Three female college soccer teams (53 subjects) participated in the study. During the first menstrual cycle, a three-step method was used to exclude subjects with anovulatory and luteal phase-deficient (LPD) (12 subjects). The subjects' menstrual cycle was divided into the menstrual phase, late-follicular phase, ovulatory phase, and mid-luteal phase (group 1, 2, 3, 4). In each phase of the second menstrual cycle, we used a portable motion analysis system to enter the teams and tested the sex hormones concentrations and knee kinematics parameters in three universities in turn. We found that subjects had a lower maximum knee valgus in group 4 compared with other groups. This meant that subjects had a lower biomechanical risk of non-contact anterior cruciate ligament (ACL) injury in the mid-luteal phase. There was no significant correlation between serum estrogen, progesterone concentration, and knee kinematic parameters. This meant that sex hormones did not have a protective effect. Future studies need to incorporate more factors (such as neuromuscular control, etc.) to investigate.

Psychophysiological Responses to Self-Selected Exercise Intensity Over the Menstrual Cycle: A Randomized Crossover Phase Trial

Purpose: This study investigated the psychophysiological responses during self-selected exercise intensity over the course of the menstrual cycle (MC). Methods: Seventeen healthy women with regular MCs completed three randomized treadmill bouts of 30 min of self-selected exercise intensity during menstruation, mid-follicular, and late luteal phases. Anxiety, menstrual distress (i.e., pain, behavior change, autonomic reaction, fluid retention, and negative affect) and profile of mood (i.e., tension, depression, and anger) were measured before exercise. Arousal, heart rate (HR), motivation, rating of perceived exertion and affective valence were measured before, during and after each exercise session. Results: Anger, anxiety, behavior change, pain, and negative affect were significantly greater (p < .05) during menstruation compared to the mid-follicular phase, whereas fluid retention, anger, behavior change, and autonomic reaction were greater (p < .05) during the late luteal phase compared with the mid-follicular phase. Participants felt more negative affective valence and less motivation to start exercise during menstruation compared with other MC phases. Average treadmill speed (5.8 ± 1.1 vs 6.0 ± 0.7 vs 5.9 ± 0.7 km/h-1, p = .36) and %HRmax (74.9 ± 3.2 vs 77.8 ± 5.4 vs 77.4 ± 7.1%, p = .40) did not differ between menstruation, mid-follicular, and late luteal phases. Also, noteworthy is that participants self-selected an intensity that exceeded the minimum levels recommended for health and cardiorespiratory fitness promotion (64-70% HRmax). Conclusions: Results of this study indicate that psychophysiological responses are negatively impacted mainly during menstruation and the late luteal phase of the MC. These findings may be helpful for professionals who work to promote the initiation and maintenance of exercise in women.

The role of sex hormones in targeting stress-induced tobacco craving, stress-reactivity, and smoking with guanfacine among women who smoke

Women who smoke are particularly vulnerable to tobacco craving, smoking behaviors, and relapse in the context of stress when compared to men who smoke. One factor in this sex difference may be sex hormones, including estradiol and progesterone; however, smoking cessation medication trials often do not explore the impact of sex hormones on drug effects. This secondary analysis of a double-blind, placebo-controlled study explored the impact of levels of actual estradiol and progesterone on guanfacine, a noradrenergic α2a agonist, which attenuates stress-induced smoking behaviors in women. Women who smoke (n = 43) completed a stress induction laboratory paradigm followed by an ad-libitum smoking period. Assessment of tobacco craving, and stress-reactivity (via cortisol response) occurred pre- and post-stress induction. Results indicated that guanfacine attenuated stress-induced tobacco craving (F = 10.94, p = 0.02) and cortisol response (F = 14.23, p < 0.001); however, high levels of estradiol overrode guanfacine's effect on craving (F = 4.00, p = 0.05), cortisol response (F = 14.23, p < 0.001), and smoking during the ad-libitum period (F = 12.23, p = 0.001). Additionally, progesterone proved to be protective against tobacco craving and enhanced guanfacine's medication effect on craving (F = 5.57, p = 0.02). The present study found that sex hormones had a significant impact on medication effects in a smoking cessation trial and thus underscore the importance of examining the role of sex hormones in future medication trials.

Determining menstrual cycle phase: An empirical examination of methodologies and recommendations for improvement in behavioral and brain sciences

The recent decade has brought an exciting proliferation of behavioral, psychological and neuroscientific research involving the menstrual cycle. However, the reliability and validity of many popular methodologies for determining menstrual cycle phase lack empirical examination. These under-investigated methods include: (1) predicting menstrual cycle phase using self-report information only (e.g., "count" methods), (2) utilizing ovarian hormone ranges to determine menstrual cycle phase, and (3) using ovarian hormone changes from limited measurements (e.g., two time points) to determine menstrual cycle phase. In the current study, we examine the accuracy of these methods for menstrual cycle phase determination using 35-day within-person assessments of circulating ovarian hormones from 96 females across the menstrual cycle. Findings indicate that all three common methods are error-prone, resulting in phases being incorrectly determined for many participants, with Cohen's kappa estimates ranging from -0.13 to 0.53 indicating disagreement to only moderate agreement depending on the comparison. Such methodological challenges are surmountable through careful study design, more frequent hormone assays (when possible), and utilization of sophisticated statistical methods. With increased methodological rigor in behavioral, psychological and neuroscientific research, the field will be poised to detect biobehavioral correlates of ovarian hormone fluctuations for the betterment of the mental health and wellbeing of millions of females.

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.

Menstrual Cycle-Associated Changes in Micronutrient Biomarkers Concentration: A Prospective Cohort Study

To evaluate variations in micronutrient biomarker concentrations and deficiencies across the menstrual cycle in a cohort of healthy women. This prospective cohort study was conducted among healthy women of reproductive age living in the State College area, Pennsylvania, (n = 45). Data collection occurred at the early follicular phase, the late follicular phase, and the midluteal phase. Fasting blood samples were collected to measure micronutrient biomarkers. At the early follicular phase, the mean ± SD concentrations for zinc, copper, magnesium, and retinol were 81.8 ± 16.2 µg/dL, 80.1 ± 12.8 µg/dL, 17.9 ± 1.4 mg/L, and 39.4 ± 9.3 µg/dL, respectively. The geometric mean (95% CI) for manganese, iron and ferritin concentrations were 1.51 [1.21, 1.87] µg/L, 106.7 [90.8, 125.4] µg/dL, and 26.4 [20.5, 34.0] µg/L, respectively. Mean concentrations of zinc and magnesium declined by 6.6% (p = 0.009) and 4.6% (p < 0.001) from the early follicular phase to the midluteal phase, respectively. Other biomarkers remained relatively constant across the cycle. At the early follicular phase, the prevalence of low serum concentrations for zinc, copper, magnesium, manganese, iron, and ferritin was 22%, 7%, 29%, 13%, 14%, and 28%, respectively. Also, in early follicular phase, 36% had anemia, and 13% specifically had iron deficiency anemia. The prevalence of magnesium deficiency was significantly higher at the midluteal phase vs. the early follicular phase (p = 0.025). Our study suggests that while many micronutrient concentrations are relatively constant across the menstrual cycle in healthy women, zinc and magnesium decline, and the prevalence of magnesium deficiency increases. Supplemental data for this article is available online at.

Underpinning the Food Matrix Regulation of Postexercise Myofibrillar Protein Synthesis by Comparing Salmon Ingestion With the Sum of Its Isolated Nutrients in Healthy Young Adults

BACKGROUND

Protein is most commonly consumed as whole foods as opposed to single nutrients. However, the food matrix regulation of the postprandial muscle protein synthetic response has received little attention.

OBJECTIVES

The purpose of this study was to assess the effects of eating salmon (SAL) and of ingesting the same nutrients as an isolated mixture of crystalline amino acids and fish oil (ISO) on the stimulation of postexercise myofibrillar protein synthesis (MPS) and whole-body leucine oxidation rates in healthy young adults.

METHODS

Ten recreationally active adults (24 ± 4 y; 5 men, 5 women) performed an acute bout of resistance exercise, followed by the ingestion of SAL or ISO in a crossover fashion. Blood, breath, and muscle biopsies were collected at rest and after exercise during primed continuous infusions of L-[ring-2H5]phenylalanine and L-[1-13C]leucine. All data are presented as means ± SD and/or mean differences (95% CIs).

RESULTS

Postprandial essential amino acid (EAA) concentrations peaked earlier (P = 0.024) in the ISO group than those in the SAL group. Postprandial leucine oxidation rates increased over time (P < 0.001) and peaked earlier in the ISO group (1.239 ± 0.321 nmol/kg/min; 63 ± 25 min) than those in the SAL group (1.230 ± 0.561 nmol/kg/min; 105 ± 20 min; P = 0.003). MPS rates for SAL (0.056 ± 0.022 %/h; P = 0.001) and ISO (0.046 ± 0.025 %/h; P = 0.025) were greater than the basal rates (0.020 ± 0.011 %/h) during the 0- to 5-h recovery period, with no differences between conditions (P = 0.308).

CONCLUSION

We showed that the postexercise ingestion of SAL or ISO stimulate postexercise MPS rates with no differences between the conditions. Thus, our results indicate that ingesting protein from SAL as a whole-food matrix is similarly anabolic to ISO in healthy young adults. This trial was registered at www.

CLINICALTRIALS

gov as NCT03870165.

A review and p-curve analysis of research on the menstrual cycle correlates of consumer preferences and economic decisions

A number of studies have been claimed to show that ovarian hormones, whose levels fluctuate throughout the menstrual cycle, affect consumer preferences and financial decisions. The present article aims to critically analyze the literature examining associations between the phases of the menstrual cycle (peri-ovulatory vs. non-ovulatory) with particular consumer preferences (especially regarding clothing choices) and economic decisions (especially in regards to economic games and risk-taking). A search for studies was conducted in Web of Science and Scopus between 2004 and 2022, by combining keywords of the menstrual cycle, consumer preferences, and economic decisions. Once articles were selected, we identified the main findings, the characteristics of the population, and the methods for determining the phases of the cycle. We performed a p-curve analysis on previously reported statistically significant effects. These analyses find evidence for associations between peri-ovulatory status and specific consumer preferences, most strongly for appearance-enhancing products. They yield no compelling evidence for associations between peri-ovulatory status and financial decisions and risk-taking. We offer provisional conclusions and call for additional studies that possess sufficient statistical power to detect true meaningful effects, especially in the domain of financial decisions.

Effect of transcranial direct current stimulation on homeostatic and hedonic appetite control and mood states in women presenting premenstrual syndrome across menstrual cycle phases

PURPOSE

This study investigated the acute effect of anodal transcranial direct current stimulation (a-tDCS) over the left dorsolateral prefrontal cortex (DLPFC) on appetite, energy intake, food preferences, and mood states in the luteal and follicular phases of the menstrual cycle in women presenting premenstrual syndrome.

METHODS

Sixteen women (26.5 ± 5.2 years; 1.63 ± 0.1 m; 64.2 ± 12.8 kg; body mass index 24.0 ± 5.0 kg/m²; body fat 27.6 ± 7.5%) with the eumenorrheic menstrual cycle were submitted to a-tDCS and sham-tDCS conditions over their follicular and luteal phases. At pre - and post-tDCS, hunger and desire to eat something tasty, (analogic visual scale), the profile of mood states (POMS), and the psychological components of food preferences (Leeds Food Preference Questionnaire-BR) were assessed. Participants recorded their food intake for the rest of the day using a diary log.

RESULTS

There was a trend towards main effect of condition for decreased implicit wanting for low-fat savory food after a-tDCS but not sham-tDCS regardless of menstrual cycle phase (p = 0.062). There was no effect for self-reported hunger, desire to eat, energy and macronutrient intake, and on other components of food preferences (explicit liking and wanting for low- and high-fat savory and sweet foods, implicit wanting for low- and high-fat sweet and high-fat savory food); as well as for mood states.

CONCLUSIONS

Although no significant effects of a-tDCS were found, the present investigation provides relevant perspectives for future studies.

Rapid effects of acute stress on cognitive emotion regulation

Acute stress has been shown to either enhance or impair emotion regulation (ER) performances. Besides sex, strategy use and stimulus intensity, another moderating factor appears to be timing of the ER task relative to stress exposure. Whereas somewhat delayed increases in the stress hormone cortisol have been shown to improve ER performances, rapid sympathetic nervous system (SNS) actions might oppose such effects via cognitive regulatory impairments. Here, we thus investigated rapid effects of acute stress on two ER strategies: reappraisal and distraction. N = 80 healthy participants (40 men & 40 women) were exposed to the Socially Evaluated Cold-Pressor Test or a control condition immediately prior to an ER paradigm which required them to deliberately downregulate emotional responses towards high intensity negative pictures. Subjective ratings and pupil dilation served as ER outcomes measures. Increases in salivary cortisol and cardiovascular activity (index of SNS activation) verified successful induction of acute stress. Unexpectedly, stress reduced subjective emotional arousal when distracting from negative pictures in men indicating regulatory improvements. However, this beneficial effect was particularly pronounced in the second half of the ER paradigm and fully mediated by already rising cortisol levels. In contrast, cardiovascular responses to stress were linked to decreased subjective regulatory performances of reappraisal and distraction in women. However, no detrimental effects of stress on ER occurred at the group level. Yet, our findings provide initial evidence for rapid, opposing effects of the two stress systems on the cognitive control of negative emotions that are critically moderated by sex.

The effects of manipulating the visual environment on thermal perception: A structured narrative review

When exposed to ambient temperatures that cause thermal discomfort, a human's behavioral responses are more effective than autonomic ones at compensating for thermal imbalance. These behavioral thermal responses are typically directed by an individual's perception of the thermal environment. Perception of the environment is a holistic amalgamation of human senses, and in some circumstances, humans prioritize visual information. Existing research has considered this in the specific case of thermal perception, and this review investigates the state of the literature examining this effect. We identify the frameworks, research rationales, and potential mechanisms that underpin the evidence base in this area. Our review identified 31 experiments, comprising 1392 participants that met the inclusion criteria. Methodological heterogeneity was observed in the assessment of thermal perception, and a variety of methods were employed to manipulate the visual environment. However, the majority of the included experiments (80%) reported a difference in thermal perception after the visual environment was manipulated. There was limited research exploring any effects on physiological variables (e.g. skin and core temperature). This review has wide-ranging implications for the broad discipline of (thermo)physiology, psychology, psychophysiology, neuroscience, ergonomics, and behavior.

Does emotion recognition change across phases of the ovulatory cycle?

Recognizing emotions is an essential ability for successful interpersonal interaction. Prior research indicates some links between the endocrine system and emotion recognition ability, but only a few studies focused on within-subject differences across distinct ovulatory cycle phases and this ability. These studies have demonstrated mixed results that might be potentially due to heterogeneity in experimental tasks, methodologies, and lacking ecological validity. In the current study, we investigated associations between within-subject differences in ovarian hormones levels and emotion recognition from auditory, visual, and audiovisual modalities in N = 131 naturally cycling participants across the late follicular and mid-luteal phase of the ovulatory cycle. We applied a within-subject design with sessions in the late follicular and mid-luteal cycle phase, and also assessed salivary progesterone and estradiol in these sessions. Our findings did not reveal any significant difference in emotion recognition ability across two cycle phases. Thus, they emphasize the necessity of employing large-scale replication studies with well-established study designs along with proper statistical analyses. Moreover, our findings indicate that the potential link between ovulatory cycle phases (late follicular and mid-luteal) and emotion recognition ability might have been overestimated in previous studies, and may contribute to theoretical and practical implications of socio-cognitive neuroendocrinology.

Light on Shedding: A Review of Sex and Menstrual Cycle Differences in the Physiological Effects of Light in Humans

The human circadian system responds to light as low as 30 photopic lux. Furthermore, recent evidence shows that there are huge individual differences in light sensitivity, which may help to explain why some people are more susceptible to sleep and circadian disruption than others. The biological mechanisms underlying the differences in light sensitivity remain largely unknown. A key variable of interest in understanding these individual differences in light sensitivity is biological sex. It is possible that in humans, males and females differ in their sensitivity to light, but the evidence is inconclusive. This is in part due to the historic exclusion of women in biomedical research. Hormonal fluctuations across the menstrual cycle in women has often been cited as a confound by researchers. Attitudes, however, are changing with funding and publication agencies advocating for more inclusive research frameworks and mandating that women and minorities participate in scientific research studies. In this article, we distill the existing knowledge regarding the relationship between light and the menstrual cycle. There is some evidence of a relationship between light and the menstrual cycle, but the nature of this relationship seems dependent on the timing of the light source (sunlight, moonlight, and electric light at night). Light sensitivity may be influenced by biological sex and menstrual phase but there might not be any effect at all. To better understand the relationship between light, the circadian system, and the menstrual cycle, future research needs to be designed thoughtfully, conducted rigorously, and reported transparently.

Comparing Gingival Inflammation And Salivary Acidity To Hormonal Variation During Menstruation

Introduction

Hormonal changes are associated with healthy female in different stages of her life, such as menarche, pregnancy, and menopause. The main female hormones (i.e., Estrogen and progesterone) act as modulators and effectors during different phases of menstrual cycle. Additionally, these hormones were shown to affect the body inflammatory status. Few studies addressed gingivitis and female hormones. Although gingivitis main cause is dental biofilm, female hormones might modulate this inflammation. If no treatment provided, gingivitis might proceed to periodontitis and alveolar bone destruction may appear.

The study aim

was to assess the changes in gingival inflammation, and salivary pH in relation to changes in hormonal levels during different menstrual phases in young females.

Method

25 healthy young females with regular menstrual cycles were included. The volunteers were invited to visit the clinic during their 2nd day of menstrual cycle (menses phase (MP)). During the visit, plaque index (PLI) and gingival index (GI) were scored. Additionally, salivary pH was calculated. Follow-up readings were taken on the 20th day of menstruation (pre-menstrual phase (PMP)). The difference in PLI, GI and salivary pH was analysed using t-test and chi-square test.

Results

The study showed that PLI and GI increased statistically significantly with increasing levels of female hormones during PMP and decreased during MP (P-value = 0.012 for PLI and 0.0003 for GI). Salivary pH decreases slightly during PMP and saliva becomes more alkaline during MP (P-value = 0.015).

Conclusion

The study showed increased gingival inflammation and plaque accumulation during the premenstrual period. It is recommended to raise awareness of gingival inflammation among adult females to prevent progressive changes of periodontitis. However, due to the limited sample size of this study, a comprehensive population-based study is needed to support the findings.

Adverse childhood experiences and hormonal contraception: Interactive impact on sexual reward function

The current literature suggests that some women are uniquely vulnerable to negative effects of hormonal contraception (HC) on affective processes. However, little data exists as to which factors contribute to such vulnerability. The present study evaluated the impact of prepubertal adverse childhood experiences (ACEs) on reward processing in women taking HC (N = 541) compared to naturally cycling women (N = 488). Participants completed an online survey assessing current and past HC use and exposure to 10 different adverse childhood experiences (ACEs) before puberty (ACE Questionnaire), with participants categorized into groups of low (0-1) versus high (≥2) prepubertal ACE exposure. Participants then completed a reward task rating their expected and experienced valence for images that were either erotic, pleasant (non-erotic), or neutral. Significant interactions emerged between prepubertal ACE exposure and HC use on expected (p = 0.028) and experienced (p = 0.025) valence ratings of erotic images but not pleasant or neutral images. Importantly, follow-up analyses considering whether women experienced HC-induced decreases in sexual desire informed the significant interaction for expected valence ratings of erotic images. For current HC users, prepubertal ACEs interacted with HC-induced decreased sexual desire (p = 0.008), such that high ACE women reporting decreased sexual desire on HC showed substantially decreased ratings for anticipated erotic images compared to both high prepubertal ACE women without decreased sexual desire (p < 0.001) and low prepubertal ACE women also reporting decreased sexual desire (p = 0.010). The interaction was not significant in naturally cycling women reporting previous HC use, suggesting that current HC use could be impacting anticipatory reward processing of sexual stimuli among certain women (e.g., high prepubertal ACE women reporting HC-induced decreases in sexual desire). The study provides rationale for future randomized, controlled trials to account for prepubertal ACE exposure to promote contraceptive selection informed by behavioral evidence.

Economic Decisions, Attractiveness, and Intrasexual Competition during Menstrual Cycle in the Ultimatum Game

Introduction

it seems that, in the phase of greatest fertility, women's intrasexual competition (toward attractive women who live nearby) increases due to access to resources, status, and biologically desirable partners.

Objective

to compare the economic decisions (ED) during the ovulatory (OP) and luteal (LP) phases of the menstrual cycle (MC) with exposure to two stimuli: a photograph of a more attractive woman and a photograph of a less attractive woman, through the ultimatum game (UG).

Methodology

the research followed a cross-sectional design between subjects to see group differences by contrasting hypotheses. The sampling was probabilistic, with a sample of 100 heterosexual women, students at a public university with an age range of 18 to 24 years, with regular MC, who did not use hormonal contraceptive methods and did not have any endocrine condition. The inverse counting method with confirmation was applied to identify CM phases; and the UG to evaluate the DE.

Results

the phases of the MC had no effect on the ED; the women behaved similarly in their decisions, regardless of the phase of the cycle they were in or the type of stimulus to which they were exposed.

Conclusion

OP and LP do not affect the ED of women when they are exposed to an attractive stimulus. The discussion is made considering the evolutionary theory of the ovulatory shift hypothesis.

Estradiol and progesterone in female reward-learning, addiction, and therapeutic interventions

Sex steroid hormones like estradiol (E2) and progesterone (P4) guide the sexual organization and activation of the developing brain and control female reproductive behavior throughout the lifecycle; importantly, these hormones modulate functional activity of not just the endocrine system, but most of the nervous system including the brain reward system. The effects of E2 and P4 can be seen in the processing of and memory for rewarding stimuli and in the development of compulsive reward-seeking behaviors like those seen in substance use disorders. Women are at increased risk of developing substance use disorders; however, the origins of this sex difference are not well understood and therapeutic interventions targeting ovarian hormones have produced conflicting results. This article reviews the contribution of the E2 and P4 in females to functional modulation of the brain reward system, their possible roles in origins of addiction vulnerability, and the development and treatment of compulsive reward-seeking behaviors.

Age at menarche relates to depression in adolescent girls: Comparing a clinical sample to the general pediatric population

CONTEXT

The timing of puberty, physical features of pubertal development, and hormones are closely intertwined but may also individually contribute to the risk for depression and depression severity. Additionally, their effects on mood may depend on depression severity, but previously this has only been studied in mostly subclinical depression.

METHODS

In 184 girls from a single psychiatric hospital with significant depressive symptoms (Beck Depression Inventory-II score > 13), the relationship between depression severity and age at menarche (AAM), pubertal status, and gonadal/adrenal hormones (estradiol, progesterone, DHEA-S, androstenedione, testosterone, dihydrotestosterone) was investigated. Moreover, AAM in depressed girls was compared to that from a representative sample of German adolescents without a psychiatric disorder (N = 1674). Androgen levels were compared to those of age- and sex-matched controls (N = 59).

RESULTS

AAM but not pubertal stage or biochemical parameters related to depression. Girls with AAM at the lower normative range of pubertal development were 61 % more likely to develop depression and scored 4.9 points higher on the depression scale than girls experiencing menarche at the population average. Androstenedione levels were increased in the psychiatric sample, but neither androgen nor gonadal hormone levels were associated with depression severity.

LIMITATIONS

The study is cross-sectional.

CONCLUSIONS

These observations confirm previous studies in mostly subclinical depression and highlight the importance of AAM for adolescent depression. Thus, AAM could be considered a prognostic factor for a clinical risk score assessing the probability of adolescent depression. Moreover, these findings suggest fostering efforts that address risk factors that contribute to an earlier AAM.

Hormone-based models for comparing menstrual cycle and hormonal contraceptive effects on human resting-state functional connectivity

Oral contraceptives (OCs) are widely used yet understudied given their potential for public health consequences. Emerging investigations scaling from single-subject, dense-sampling neuroimaging studies to population-level metrics have linked OCs to altered brain structure and function. Modeling the hypogonadal, hypergonadal, or mixed state effects of OCs in terms of their impact on hormone action in the brain is a valuable approach to synthesizing results across neuroimaging studies and comparing OC effects to companion findings from research on menstrual cycle phase effects on brain anatomy and function. Resting-state functional connectivity studies provide a powerful tool to evaluate the role of OCs on the intrinsic network connectivity that underlies multiple behavioral domains. The preponderance (but not consensus) of the current literature indicates that (1) as the menstrual cycle proceeds from a low to high progesterone state, prefrontal connectivity increases and parietal connectivity decreases; (2) OCs tend to mimic this connectivity pattern; therefore (3) OCs may produce a hyperprogestogenic state in the brain, in spite of overall reductions in endogenous steroid hormone levels. Alternative models are also considered.

Training, Wellbeing and Recovery Load Monitoring in Female Youth Athletes

Participation in youth sports is ever-increasing, along with training and competition demands placed upon youth athletes. Young athletes may experience high training loads due to playing several sports, as well as participating in school physical education. Therefore, monitoring youth athlete load is an emerging area of research that may help limit non-functional overreaching, injury, or illness and assist with long-term athlete development. This narrative review highlights that multiple measures have been explored to monitor both internal and external load. However, the validity, reliability and practicality of these measures are often not fully understood in female youth populations. The most commonly used external monitoring methods are GPS tracking and TRIMP whereas common internal monitoring tools are questionnaires, perceived exertion rating and heart rate measures. The reporting of injuries and menstrual cycles is also crucial for providing completeness when monitoring an athlete. It has been suggested that the combination of training load, recovery and wellbeing monitoring variables is the optimal way to monitor an athlete's fatigue levels. Whichever monitoring method is applied, in a youth population it is important that the protocol can be individualised, is inexpensive and can be easily implemented and reported so that the monitoring is sustainable.

Tracking of menstrual cycles and prediction of the fertile window via measurements of basal body temperature and heart rate as well as machine-learning algorithms

BACKGROUND

Fertility awareness and menses prediction are important for improving fecundability and health management. Previous studies have used physiological parameters, such as basal body temperature (BBT) and heart rate (HR), to predict the fertile window and menses. However, their accuracy is far from satisfactory. Additionally, few researchers have examined irregular menstruators. Thus, we aimed to develop fertile window and menstruation prediction algorithms for both regular and irregular menstruators.

METHODS

This was a prospective observational cohort study conducted at the International Peace Maternity and Child Health Hospital in Shanghai, China. Participants were recruited from August 2020 to November 2020 and followed up for at least four menstrual cycles. Participants used an ear thermometer to assess BBT and wore the Huawei Band 5 to record HR. Ovarian ultrasound and serum hormone levels were used to determine the ovulation day. Menstruation was self-reported by women. We used linear mixed models to assess changes in physiological parameters and developed probability function estimation models to predict the fertile window and menses with machine learning.

RESULTS

We included data from 305 and 77 qualified cycles with confirmed ovulations from 89 regular menstruators and 25 irregular menstruators, respectively. For regular menstruators, BBT and HR were significantly higher during fertile phase than follicular phase and peaked in the luteal phase (all P < 0.001). The physiological parameters of irregular menstruators followed a similar trend. Based on BBT and HR, we developed algorithms that predicted the fertile window with an accuracy of 87.46%, sensitivity of 69.30%, specificity of 92.00%, and AUC of 0.8993 and menses with an accuracy of 89.60%, sensitivity of 70.70%, and specificity of 94.30%, and AUC of 0.7849 among regular menstruators. For irregular menstruators, the accuracy, sensitivity, specificity and AUC were 72.51%, 21.00%, 82.90%, and 0.5808 respectively, for fertile window prediction and 75.90%, 36.30%, 84.40%, and 0.6759 for menses prediction.

CONCLUSIONS

By combining BBT and HR recorded by the Huawei Band 5, our algorithms achieved relatively ideal performance for predicting the fertile window and menses among regular menstruators. For irregular menstruators, the algorithms showed potential feasibility but still need further investigation.

TRIAL REGISTRATION

ChiCTR2000036556. Registered 24 August 2020.

Do E2 and P4 contribute to the explained variance in core temperature response for trained women during exertional heat stress when metabolic rates are very high?

Purpose

Women remain underrepresented in the exercise thermoregulation literature despite their participation in leisure-time and occupational physical activity in heat-stressful environments continuing to increase. Here, we determined the relative contribution of the primary ovarian hormones (estrogen [E₂] and progesterone [P₄]) alongside other morphological (e.g., body mass), physiological (e.g., sweat rates), functional (e.g., aerobic fitness) and environmental (e.g., vapor pressure) factors in explaining the individual variation in core temperature responses for trained women working at very high metabolic rates, specifically peak core temperature (T_peak) and work output (mean power output).

Methods

Thirty-six trained women (32 ± 9 year, 53 ± 9 ml·kg⁻¹·min⁻¹), distinguished by intra-participant (early follicular and mid-luteal phases) or inter-participant (ovulatory vs. anovulatory vs. oral contraceptive pill user) differences in their endogenous E₂ and P₄ concentrations, completed a self-paced 30-min cycling work trial in warm–dry (2.2 ± 0.2 kPa, 34.1 ± 0.2 °C, 41.4 ± 3.4% RH) and/or warm–humid (3.4 ± 0.1 kPa, 30.2 ± 1.2 °C, 79.8 ± 3.7% RH) conditions that yielded 115 separate trials. Stepwise linear regression was used to explain the variance of the dependent variables.

Results

Models were able to account for 60% of the variance in T_peak (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{R }$$\end{document}R¯²: 41% core temperature at the start of work trial, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{R }$$\end{document}R¯²: 15% power output, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{R }$$\end{document}R¯²: 4% [E₂]) and 44% of the variance in mean power output (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{R }$$\end{document}R¯²: 35% peak aerobic power, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{R }$$\end{document}R¯²: 9% perceived exertion).

Conclusion

E₂ contributes a small amount toward the core temperature response in trained women, whereby starting core temperature and peak aerobic power explain the greatest variance in T_peak and work output, respectively.