Effect Of Menstrual Cycle Research Articles

243-OR: Effect of Menstrual Cycle on Glycemic Responses to Exercise in Female Participants with Type 1 Diabetes

Fear of hypoglycemia is a major barrier to exercise in people with type 1 diabetes (T1D) . Females with T1D tend to be less active than males with T1D, which might be due to significant knowledge gaps around blood glucose responses to exercise, especially with regards to the menstrual cycle. We compared the effect of a moderate aerobic exercise (cycling at 50% of pre-determined VO2peak for 45 min) on glycemic responses between the early follicular and late luteal phases of the menstrual cycle in 9 female participants with T1D (mean±SD: age 30.2±9 years, A1C 7.4±0.7%, VO2peak 32.5±4.2 mL/kg/min) with regular menstrual cycles not using oral contraceptives. In both phases, serum glucose decreased from pre to post exercise and increased throughout the 60-min recovery (effect of time p<0.05) but was not significantly different between the two phases (effect of phase p>0.05) . Serum insulin (log transformed) decreased from pre to post exercise in both phases (effect of time p<0.05) but was not significantly different between the two phases (effect of phase p>0.05) . The number of participants needing glucose supplementation (Dex4) to prevent hypoglycemia before and during exercise and recovery was significantly higher in the luteal versus the follicular phase (6/9 vs. 1/9, Fisher’s p=0.049) . Continuous glucose monitoring, however, showed no increase in the number of hypoglycemic episodes post exercise during the luteal phase. There were more post-exercise hyperglycemic episodes in the follicular versus the luteal phase (3±0.5 vs. 1.3±0.3, p=0.029) . These data suggest that females with T1D may be more prone to post-exercise hyperglycemia during the follicular phase, while needing more glucose supplementation to prevent hypoglycemia during the luteal phase of the menstrual cycle. These data should help guide recommendations for carbohydrate and insulin adjustment. Disclosure Z.Momeni: None. J.E.Yardley: Research Support; Abbott, Dexcom, Inc., LifeScan, Speaker's Bureau; Abbott Diabetes.

Physiological background parenchymal uptake of 18F-FDG in normal breast tissues using dedicated breast PET: correlation with mammographic breast composition, menopausal status, and menstrual cycle

This study aimed to quantitatively evaluate the effects of age, mammographic density, menopausal status, and menstrual cycle on background parenchymal uptake (BPU) using ring-shaped dedicated breast positron emission tomography (dbPET). This study included 186 adult women who underwent mammography and dbPET on the same day and had no abnormalities classified as Breast Imaging Reporting and Data System (BI-RADS) category 1 on both examinations. The volume of interest (VOI) was placed in the glandular tissue of both breasts, and the maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), and metabolic breast volume (MBV) were measured as indicators of BPU. We analyzed the correlation between BPU and age, mammographic density, menopausal status, and menstrual cycle. The SUVmax and SUVmean for normal breast tissue were inversely correlated with age (both p < 0.001). The SUVmax, SUVmean, and MBV of mammographically dense breast tissues were significantly higher than those of non-dense breast tissues (all p < 0.001). The SUVmax, SUVmean, and MBV of normal breast tissue in premenopausal women were significantly higher than those in postmenopausal women (p < 0.001, p < 0.001, p = 0.002, respectively). In the study, 59 premenopausal women, the SUVmax of normal breast tissue in the menstrual-follicular phase was significantly lower than that in the periovulatory-luteal phase (p = 0.02). When we sorted the premenopausal women by mammographic breast composition, the SUVmax and SUVmean of normal breast tissues in the menstrual-follicular phase were significantly lower than those in the periovulatory-luteal phase in the 44 premenopausal women with dense breasts (p = 0.007, and p = 0.038, respectively), whereas no statistically significant difference was found between the menstrual-follicular phase and the periovulatory-luteal phase in the 15 premenopausal women with non-dense breasts. BPU in normal breast tissues assessed using ring-shaped dbPET was associated with mammographic density, menopausal status, and women's menstrual cycle. The menstrual cycle was significantly associated with BPU in premenopausal women with dense breasts but not in women with non-dense breasts.

Heart rate variability during different phases of menstrual cycle

The purpose of the present study was to determine whether there is a menstrual cycle effect on heart rate variability. Ten healthy regularly cycling females (age 19‐23 years) were studied during the follicular phase (FP) and luteal phase (LP) of menstrual cycle over two month. We found significant changes in heart rate (65,35±0,68 beats/min in FP vs 73,18±0,92 beats/min in LP, p&lt;0,0005), AMo and stress index during the menstrual cycle with a minimum in the follicular phase (36,81±1,14 % and 76,86±5,74 p.d.u. respectively) and maximum in the luteal phase (42,05±1,27 % and 107,70±7,77 p.d.u. respectively, p&lt;0,003). The HF and LF components decreased more during the luteal phase (655,56±46,64 ms2 and 981,85±66,64 ms2 respectively) than during the follicular phase (997,42±83,36 ms2 and 1524,66±145,17 ms2 respectively, p&lt;0,05). In the follicular phase SDNN, pNN50, MxDMn were significantly higher (0,057±0,002 s, 41,49±1,79 % and 0,333±0,012 s respectively) than in the luteal phase (0,051±0,002 s, 29,73±1,88 % and 0,303±0,012 s respectively, p&lt;0,05). Furthermore, the VIK was higher in the luteal phase compared to the follicular phase (p=0,003). These findings indicate that sympathetic nervous activity in the luteal phase is greater than in the follicular phase, whereas parasympathetic nervous activity is predominant in the follicular phase. A difference of the balance of ovarian hormones may be responsible for these changes of autonomic functions during the menstrual cycle.

Cardiovascular Fitness Improves Cardiac Interoceptive Accuracy

Background. Many of the sensory receptors encoding touch, temperature, pain, and visual or auditory cues are known; these exteroceptive receptors allow us to respond to external threats. The interoceptive sensory receptors that identify stimuli within the internal milieu, e.g. changes in our heart rate, gastric fullness, or breathing difficulty are not known. We postulated mechanosensitive piezo channels in the heart are responsible for cardiac interoception. We found that individuals with lower resting heart rates and resting rate‐pressure products, and higher heart rate variability and stroke volumes have greater interoceptive accuracy. These characteristics often result from exercise training.HypothesisWe suggest that individual contrasts in interoceptive accuracy will correlate with genotypic differences in the PIEZO 1 channels in the population and individual variation in fitness levels. Furthermore, activities that increase stroke volume, such as thermal warming, would enhance interoceptive accuracy.MethodsHeart rates, blood pressures, and stroke volumes were measured non‐invasively in 12 healthy men and women using a commercial photoplethysmography device (Finapres,™ Nova Instruments). Fitness levels were assessed using a modified Harvard step test. Cardiac interoceptive accuracy (“IA”) was assessed using a heartbeat tracking task where participants counted their heartbeats during four separate trials after being instructed not to take their pulse or engage in any manipulation that could facilitate heartbeat detection while their EKG was being recorded. “IA” was calculated from 1/4 Σ [1 – (|EKG heartbeats – reported heartbeats|) ÷ EKG heartbeats]; higher scores represent greater interoceptive accuracy. “IA” was assessed while subjects rested supine in a room at 68o F and after warming with thermal blankets for 25‐30 min. Because of confounding effects of menstrual cycle on body temperature, we studied the effect of thermal warming only on men. Because PIEZO 1 channels also mediate regulatory volume changes to osmotic stress, we assessed PIEZO 1 channel‐mediated hemolysis of erythrocytes during hypotonic stress.Results. Cardiac “IA” correlated positively with fitness levels (n = 9, r = 0.59, p &lt; 0.05). Furthermore, the EC50 calculated from an osmotic fragility test on erythrocytes from our subjects correlated with their “IA” (n = 6, r = 0.91, p = 0.01). Thermal heating raised forearm skin temperatures (values expressed as mean oC + SEM) from 36.3 + 0.2 to 37.9 + 0.18 (n = 10, p &lt; 0.0001) which was accompanied by an increase in “IA” scores from (values in arbitrary units + SEM) 83.3 + 3.2 to 89.5 + 2.6 (n = 10, p = 0.002). Surprisingly, mild thermal heating did not affect resting heart rate or vascular resistance, but stroke volume tended to fall (values expressed in ml/beat + SEM) from 102 + 5.6 to 92 + 5.6 (n = 6, p = 0.03).Conclusions. Increasing fitness levels and endogenous PIEZO 1 channel activity correlate with enhanced “IA.” Although the individual’s stroke volume may be a determinant of their “IA,” this self‐awareness of heart beats and other interoceptive clues are sensitive to environmental factors such as mild thermal heating.

Effect of oral hormonal contraceptive pill use on the hemodynamic response to the cold pressor test.

Acute increases in sympathetic nervous system activity (SNA) often elicit peripheral vasoconstriction and increases in blood pressure (BP). Given sympathetic support of BP is modulated by ovarian sex hormones (e.g., estradiol), we sought to examine the effect of menstrual cycle and oral hormonal contraceptive pill (OC) phase on the hemodynamic response to acute increases in SNA. We hypothesized sympathoexcitation via cold pressor test (CPT) would elicit greater peripheral vasoconstriction and increases BP in females with natural menstrual cycles (NC) compared with females taking OC. We further hypothesized that SNA-mediated vasoconstriction would be attenuated during the high estradiol (HE) phase versus the low estradiol (LE) phase of the menstrual/pill cycle. Female NC (n = 11, 25 ± 1 yr) and OC (n = 10, 24 ± 1 yr) participants were studied during the LE (early follicular, placebo pill) and HE (late follicular, active pill) phase of the menstrual/pill cycle. BP (finger photoplethysmography), heart rate (HR, ECG), and forearm blood flow (FBF, venous occlusion plethysmography) were measured during a 5-min baseline and a 2-min CPT. CPT elicited an increase in BP in both groups (time, P < 0.01). During CPT, OC participants exhibited greater and sustained increases in HR compared with NC participants (group × time, P < 0.01). Higher HRs were met with increases in FBF in OC participants during the CPT, which was not observed in NC participants (group × time, P < 0.01). OC participants exhibit greater increases in HR, and paradoxical vasodilation during acute sympathetic activation compared with NC participants. Group differences are unaffected by menstrual/pill phase.NEW & NOTEWORTHY Acute increases in sympathetic nervous system activity often elicit peripheral vasoconstriction and increases in blood pressure (BP). Given sympathetic support of BP is modulated by ovarian sex hormones (e.g., estradiol), we sought to examine the effect of menstrual cycle and oral hormonal contraceptive pill (OC) phase on the hemodynamic response to acute increases in sympathetic nervous system activity via the cold pressor test. We show OC participants exhibit paradoxical vasodilation during acute sympathetic activation compared with participants with natural menstrual cycles; notably, group differences were unaffected by menstrual/pill phase.

Menstrual cycle effects on sleep

Sleep and menstrual cycle both are normal physiological processes in women’s life but they are regulated by different centers. Sleep is a daily rhythm whereas the menstrual cycle lasts for 28 days. During this period the estrogen peaks twice. We have shown earlier that there is an inverse relationship between estrogen and the hormone melatonin which aids sleep. Because of this menstruating women will have sleep disorders.

Effects of Menstrual Cycle on the Accumulation of Human Papillomavirus-Infected Cells Exfoliated from the Cervix That Drift into the Vagina.

Human papillomavirus (HPV) testing using self-collected vaginal specimens is the preferred choice to increase screening uptake. Although the HPV testing results of these samples depend on the cells that naturally exfoliate from the cervical lesion and drift into the vagina, the mechanism of when and how these exfoliated cells mix with the self-collected sample remains unclear. Hence, the study aimed to clarify the relationship between the vaginal drift of HPV-infected cells exfoliated from the cervix, and the menstrual cycle. A total of 180 scraped samples of the cervix and vagina were examined. The exfoliated cells were classified into two categories according to the HPV genotyping results of each sample: sufficient accumulation (same HPV types in cervical and vaginal samples) and insufficient accumulation (fewer HPV types in vaginal samples than in cervical samples, or HPV positivity in cervical samples and HPV negativity in vaginal samples). A moderately strong statistically significant association was observed between exfoliated cell accumulation and the menstrual cycle, and insufficient accumulation was statistically significantly increased at the early proliferative phases. Self-collection of vaginal samples at the early proliferation phase indicates insufficient sample quantities or lower viral load, thereby affecting HPV genotyping.

Impact of menstrual cycle events on bipolar disorder course: a narrative review of current evidence.

Several lines of research suggest that reproductive-related hormonal events may affect the course of bipolar disorder in some women. However, data on associations between bipolar disorder and menarche, menstrual cycle, and menopause are mixed. This article reviews the literature on the potential effects of menarche, menstrual cycle, and menopause on bipolar disorder.A narrative review of published articles on bipolar disorder and menstrual cycle eventswas conducted. The primary outcome assessed was the impact of menarche, menstrual cycle and menopause on the course of bipolar illness.Databases searched were PubMed, Ovid, Scopus, PsycINFO, Medline, and Cochrane Libraries from inception to August 2021.Twenty-twostudies were identified and included in the narrative synthesis. Research suggested that a subset of women with bipolar disorder are vulnerable to the impact of menstrual cycle events. Menarche seems to be associated with age atonset of bipolar illness especially in case of bipolar disorder type I and the specific age at menarche may predict some clinical features of the disorder. Menstrual cycle likely affects the course of bipolar disorder but the pattern of mood variability is not clear. Menopause appears to be not only a period of vulnerability to mood alteration, especially depressive episodes, and impairment of quality of life, but also a potential trigger of bipolar illness onset.The impact of menarche, menstrual cycle, and menopause on bipolar disorder is largely understudied. Preliminary evidence suggests that a subset of women with bipolar disorder may have their mood shifts affected by menstrual cycle events, with different patterns depending on the type of bipolar disorder also. Further researches are needed to deep the impact of menarche, menstrual cycle, and menopause on bipolar illness.

The effect of menstrual cycle on anaerobic power and jumping performance

Background and Study Aim. There has been a significant increase in the participation levels of women in competitive sports in recent years. This has contributed to the increase of research on women's participation in sports and their health. The aim of this study is to investigate the effect of the menstrual cycle on anaerobic power and jumping performance. Material and Methods. In this study, 15 female athletes between the ages of 18-24, who have a regular menstrual cycle for the last 6 months Wingate Anaerobic Power Test and Active Jumping Test applied to athletes during their menstrual phases (second day of the menstruation period) and follicular phases (14th day of the menstruation period). In the statistical analysis of the data, descriptive analyses of test measurements of athletes were calculated as mean and standard deviation. Whether there is a significant difference between the measurements taken on two different days was analyzed using the t-test in dependent groups. Results. It was determined that the anaerobic power and active jump performances of the participants had an effect on peak power, fatigue index and active jump performance between day 2 and day 14 values. Also, there was a statistically significant difference between these values (p&lt;0.05). Conclusions. This situation can be explained as a result of the hormonal changes in the menstrual period of the athletes and the effects of psychological factors specific to this period.

Effects of menstrual cycle on appetite-regulating hormones and energy intake in response to cycling exercise in physically active women.

Although ample evidence supports the notion that an acute bout of endurance exercise performed at or greater than 70% of maximum oxygen uptake suppresses appetite partly through changes in appetite-regulating hormones, no study has directly compared the influence between the phases of the menstrual cycle in women. This study compared the effects of an acute bout of exercise on orexigenic hormone (acylated ghrelin) and anorexigenic hormones (peptide YY and cholecystokinin) between the early follicular phase (FP) and the mid luteal phase (LP) of the menstrual cycle in physically active women. Ten healthy women (age, 20.6 ± 0.7 yr) completed two 3.5-h trials in each menstrual phase. In both trials, participants performed cycling exercises at 70% of heart rate reserve (at a corresponding intensity to 70% of maximum oxygen uptake) for 60 min followed by 90 min of rest. Following 90 min of rest, participants were provided with an ad libitum meal for a fixed duration of 30 min. Blood samples and subjective appetite were collected and assessed before exercise, during exercise, immediately postexercise, 45 min postexercise, and 90 min postexercise. The exercise increased estradiol (327%) and progesterone (681%) in the LP more than the FP, respectively (P < 0.001, f = 1.33; P < 0.001, f = 1.20). There were no between-trial differences in appetite-regulating hormones, subjective appetite, or energy intake of ad libitum meal. These findings indicate that exercise-induced increases in ovarian hormones in the LP may not influence appetite-regulating hormones in physically active women.NEW & NOTEWORTHY To our knowledge, this is the first study to compare how different phases of the menstrual cycle influence appetite-regulating hormones after acute exercise in healthy women. There were no differences in appetite-regulating hormones between the early follicular and mid luteal phases, whereas ovarian hormones were remarkably increased by cycling exercise in the mid luteal phase. These results highlight that appetite-regulating hormones in response to exercise do not appear to be influenced by the menstrual cycle.

Mapping changes in women's visual functions during the menstrual cycle: narrative review.

This article systematically updates the literature on changes in visual functions during the phases of the normal menstrual cycle in women. To update Guttridge's 1994 review of visual structures and functions associated with the menstrual cycle and broaden the search through psychophysical, neuroimaging and neurobehavioral measurements covering 1994-2020. Narrative review conducted in a neurosciences and behavior laboratory in Brazil. The PubMed, Cochrane Clinical Answers and Google Scholar databases were searched. After screening and applying the eligibility criteria, 32 articles were examined. Through this analysis, the following information was extracted: (1) geographical distribution of the study; (2) sample size (according to age and phase of the menstrual cycle); (3) type of measurements according to psychophysical, neuroimaging and neurobehavioral instruments; (4) vision testing model; (5) visual subcategory evaluated; (6) categories of processed visual stimuli; and (7) main findings. The menstrual phases give rise to significant changes in visual functions, including in relation to orientation and spatial attention, visual campimetry and visual sensitivity. These relate specifically to the follicular and luteal phases. These findings theoretically expand the effects of menstrual cycles on visual functions found by Guttridge (1994). Despite some inconsistencies in the studies analyzed, it was found that visual processing during the follicular and luteal phases of the normal menstrual cycle of healthy women can explain physiological, cognitive, behavioral and social modulations.

Assessment of choroidal vascularity index during the menstrual cycle.

To explore the effect of menstrual cycle on choroidal vascularity index (CVI). Thirty six eyes of 36 healthy women were included in this prospective study. The menstrual cycles were regular and ranged from 28 to 30 days in length. Optical coherence tomography images were obtained in 3 different phases of the menstrual cycle. The choroidal thickness (CT), total choroidal area, luminal area, stromal area, and CVI were quantified. Mean subfoveal, nasal and temporal CT were significantly changed in mid-luteal phase in comparison to early follicular (p = 0.018, p = 0.006 and p = 0.001, respectively) and ovulatory phases (p = 0.037, p = 0.037, and p = 0.035, respectively). Mean CVI showed a significant change in mid-luteal phase when compared with early follicular (p = 0.001) and ovulatory phases (p = 0.036). CVI seemed to be affected in mid-luteal phase of menstrual cycle. This should be considered while analyzing choroidal structure in otherwise healthy women.

Menstrual cycle effects on sympathetic neural burst amplitude distribution during orthostasis in young women.

Fluctuations in ovarian hormones during the menstrual cycle impact muscle sympathetic nerve activity burst frequency and burst incidence at rest. The purpose of this study was to investigate menstrual cycle effects on sympathetic neural burst amplitude distribution during an orthostatic challenge in young women. This study included 11 healthy women (33 ± 10years [mean ± standard deviation]). Muscle sympathetic nerve activity was measured in the supine position as baseline measurement and during 5 min of 60° upright tilting, during the early follicular phase (low estrogen and progesterone) and mid-luteal phase (high estrogen and progesterone) of the menstrual cycle. Relative burst amplitude distribution of muscle sympathetic nerve activity was characterized by the mean, median, skewness, and kurtosis. From the supine to upright position, mean and median values of relative burst amplitude increased (both P < 0.05), regardless of phases of the menstrual cycle (P = 0.5 and P = 0.7, respectively). In comparison, during the early follicular phase, skewness and kurtosis remained unchanged (P = 0.6 and P = 0.3, respectively) and kurtosis decreased (1.25 ± 1.11 supine vs. -0.03 ± 0.73 upright; P = 0.02); there was no change in skewness during the mid-luteal phase (P = 0.4). In response to orthostasis, while the symmetry and tailedness/peakness of burst amplitude distribution do not change during the early follicular phase, the distribution during the mid-luteal phase becomes flatter with a lower but broader peak. The latter result suggests that the firing probability of large axon action potentials in response to orthostatic challenge is higher when estrogen and progesterone levels are elevated. The role of changes in sympathetic neural burst amplitude distribution in orthostatic tolerance remains to be determined.

Effects of menstrual cycle on divided attention in dual-task performance

Purpose Monthly hormonal fluctuation in women causes changes in peripheral systems and central nervous system structure and functions. In this study, we investigated the effects of menstrual cycle periods in women on attention during multitasking. Single and dual task conditions were tested in different menstrual cycle periods. Materials and methods A total of forty women with regular menstrual cycles participated in this study. They were not any type of medication or hormonal treatment. Fine motor skills and Go/No-go tasks were performed on the 10th day of the late follicular phase, and then the tests were repeated on the 20th day of the late luteal phase. Fine motor tasks were performed by Annett's peg-moving test. Auditory stimuli were used in Go/No-go task. In dual tasks, both tasks were performed simultaneously. Results There was no difference between follicular and luteal phases in single fine motor and Go/No-go task. In dual task condition Go/No-go task % error rate decreased in the luteal phase. Similarly, Go/No-go task reaction time decreased in the luteal phase. Non-dominant hand performance was increased in the luteal phase during the dual-task condition compared to the follicular phase. Conclusions When these results are evaluated together, declining error rates and reaction times indicates women successfully multitask in the luteal phase in dual tasks condition. This suggests that divided attention in women leads to better performance in the luteal phase than in the follicular phase.

Effect of menstrual cycle and female hormones on TRP and TREK channels in modifying thermosensitivity and physiological functions in women.

Thermoregulation is crucial for human survival at various ambient temperatures. Transient receptor potential (TRP) and TWIK-related K+ (TREK) channels expressed in sensory neurons play a role in peripheral thermosensitivity for temperature detection. In addition, these channels have various physiological roles in the skeletal, nervous, immune, vascular, digestive, and urinary systems. In women, the female hormones estradiol (E2) and progesterone (P4), which fluctuate during the menstrual cycle, affect various physiological functions, such as thermoregulation in hot and cold environments. The present review describes the effect of female hormones on TRP and TREK channels and related physiological functions. The P4 decreased thermosensitivity via TRPV1. E2 facilitates temporomandibular joint disease (TRPV1), breast cancer (TRPM8), and calcium absorption in the digestive system (TRPV5 and TRPV6), inhibits the facilitation of vasoconstriction (TRPM3), nerve inflammation (TRPM4), sweetness sensitivity (TRPM5), and menstrual disorders (TRPC1), and prevents insulin resistance (TRPC5) via each channel. P4 inhibits vasoconstriction (TRPM3), sweetness sensitivity (TRPM5), ciliary motility in the lungs (TRPV4), menstrual disorder (TRPC1), and immunity (TRPC3), and facilitates breast cancer (TRPV6) via each channel as indicated. The effects of female hormones on TREK channels and physiological functions are still under investigation. In summary, female hormones influence physiological functions via some TRP channels; however, the literature is not comprehensive and future studies are needed, especially those related to thermoregulation in women.

Commentary on Joyce et al.: Studying menstrual cycle effects on behavior requires within-person designs and attention to individual differences in hormone sensitivity.

Commentary on Joyce et al.: Studying menstrual cycle effects on behavior requires within-person designs and attention to individual differences in hormone sensitivity.

Effects of sex and menstrual cycle on sweating during isometric handgrip exercise and postexercise forearm occlusion.

What is the central question of this study? Do sex and menstrual cycle modulate sweating during isometric handgrip exercise and muscle metaboreceptor stimulation? What is the main finding and its importance? Sex modulates sweating during isometric handgrip exercise, as indicated by the lower sweat output per gland in women than in men, but not during muscle metaboreceptor stimulation. Sweat output per gland during isometric handgrip exercise and muscle metaboreceptor stimulation were lower in the mid-luteal phase than in the early follicular phase in women. Cholinergic sweat gland sensitivity might explain, in part, the individual variation of the response. Our results provide new insights regarding sex- and menstrual cycle-related modulation of the sweating response. We investigated whether sex and menstrual cycle could modulate sweating during isometric handgrip (IH) exercise and muscle metaboreceptor stimulation. Twelve young, healthy women in the early follicular (EF) and mid-luteal (ML) phases and 14 men underwent two experimental sessions consisting of a 1.5min IH exercise at 25 and 50% of maximal voluntary contraction (MVC) in a hot environment (35°C, relative humidity 50%) followed by 2min forearm occlusion to stimulate muscle metaboreceptors. Sweat rates, the number of activated sweat glands and the sweat output per gland (SGO) on the forearm and chest were assessed. Pilocarpine-induced sweating was also assessed via transdermal iontophoresis to compare the responses with those of IH exercise and muscle metaboreceptor stimulation, based on correlation analysis. Sweat rates on the forearm and chest during IH exercise and muscle metaboreceptor stimulation did not differ between men and women in either menstrual cycle phase (all P ≥ 0.144). However, women in both phases showed lower SGO on the forearm and/or chest compared with men during IH exercise at 50% of MVC, with no differences in muscle metaboreceptor stimulation. Women in the ML phase had a lower forearm sweat rate during IH exercise at 50% of MVC (P=0.015) and SGO during exercise and muscle metaboreceptor stimulation (main effect, both P ≤ 0.003) compared with those in the EF phase. Overall, sweat rate and SGO during IH exercise and muscle metaboreceptor stimulation were correlated with pilocarpine-induced responses (all P ≤ 0.064, r ≥ 0.303). We showed that sex and menstrual cycle modulate sudomotor activity during IH exercise and/or muscle metaboreceptor stimulation. Cholinergic sweat gland sensitivity might explain, in part, the individual variation of the response.

The Female Menstrual Cycles Effect on Strength and Power Parameters in High-Level Female Team Athletes.

PurposeThe female menstrual cycle (MC) is characterized by hormonal fluctuations throughout its different phases. However, research regarding its effect on athletic performance in high level athletes is sparse. The aim of this study was to (i) investigate the female MCs effect on strength and power performance in highly trained female team athletes throughout the MC and (ii) examine whether eumenorrheic participants with natural hormonal fluctuations displayed enhanced performance in the follicular phase (FP) versus the luteal phase (LP), compared to controls using hormonal contraceptives.Materials and MethodsA total of 29 athletes (Age 21.2 ± 3.3 years; weight 65.6 ± 8.7 kg; height 170.2 ± 8.0 cm; and fat free mass 52.7 ± 7.1) completed the study after a 6-week testing period (8 eumenorrheic participants and 21 hormonal contraceptive controls). Participants were recruited from the team sports soccer, handball and volleyball. Testing protocol consisted of maximal voluntary isometric grip strength, 20-m sprint, countermovement jump and pneumatic leg-press. Based on self-reported use of hormonal contraceptives, participants were divided into non-hormonal contraceptive group and hormonal contraceptive group, the latter working as a control group. Differences in performance between the FP and LP were investigated. MC phase was confirmed by serum hormonal levels through venous blood samples in the non-hormonal contraceptive group.ResultsThere were no statistically significant changes for the two different phases of the MC, in terms of physical performance for the whole group. Further, there was no significant difference between groups during the MC for any of the outcome variables, maximal voluntary isometric grip strength F(3.29) = 0.362; 20-m sprint F(3.24) = 0.710; countermovement jump F(3.26) = 2.361; and leg-press F(3.26) = 1.746.ConclusionIn high level female team athletes, no difference in performance was observed based on hormonal contraceptive status. This suggests that the MC does not alter acute strength and power performance on a group level in high level team athletes.

Guidelines for biomarker discovery in endometrium: correcting for menstrual cycle bias reveals new genes associated with uterine disorders.

Transcriptomic approaches are increasingly used in reproductive medicine to identify candidate endometrial biomarkers. However, it is known that endometrial progression in the molecular biology of the menstrual cycle is a main factor that could affect the discovery of disorder-related genes. Therefore, the aim of this study was to systematically review current practices for considering the menstrual cycle effect and to demonstrate its bias in the identification of potential biomarkers. From the 35 studies meeting the criteria, 31.43% did not register the menstrual cycle phase. We analysed the menstrual cycle effect in 11 papers (including 12 studies) from Gene Expression Omnibus: three evaluating endometriosis, two evaluating recurrent implantation failure, one evaluating recurrent pregnancy loss, one evaluating uterine fibroids and five control studies, which collected endometrial samples throughout menstrual cycle. An average of 44.2% more genes were identified after removing menstrual cycle bias using linear models. This effect was observed even if studies were balanced in the proportion of samples collected at different endometrial stages or only in the mid-secretory phase. Our bias correction method increased the statistical power by retrieving more candidate genes than per-phase independent analyses. Thanks to this practice, we discovered 544 novel candidate genes for eutopic endometriosis, 158 genes for ectopic ovarian endometriosis and 27 genes for recurrent implantation failure. In conclusion, we demonstrate that menstrual cycle progression masks molecular biomarkers, provides new guidelines to unmask them and proposes a new classification that distinguishes between biomarkers of disorder or/and menstrual cycle progression.

Daily, weekly, seasonal and menstrual cycles in women's mood, behaviour and vital signs.

Dimensions of human mood, behaviour and vital signs cycle over multiple timescales. However, it remains unclear which dimensions are most cyclical, and how daily, weekly, seasonal and menstrual cycles compare in magnitude. The menstrual cycle remains particularly understudied because, not being synchronized across the population, it will be averaged out unless menstrual cycles can be aligned before analysis. Here, we analyse 241 million observations from 3.3 million women across 109 countries, tracking 15 dimensions of mood, behaviour and vital signs using a women's health mobile app. Out of the daily, weekly, seasonal and menstrual cycles, the menstrual cycle had the greatest magnitude for most of the measured dimensions of mood, behaviour and vital signs. Mood, vital signs and sexual behaviour vary most substantially over the course of the menstrual cycle, while sleep and exercise behaviour remain more constant. Menstrual cycle effects are directionally consistent across countries.