Midluteal Research Articles

Menstrual Phase Affects Coagulation and Hematological Parameters during Central Hypovolemia.

Background: It has been reported that women have a higher number of heart attacks in the “follicular phase” of the menstrual cycle. We, therefore, tested the hypothesis that women in the follicular phase exhibit higher coagulability. As lower body negative pressure (LBNP) has been used previously to assess coagulation changes in whole blood (WB) samples in men and women, effects of menstrual phase on coagulation was assessed during LBNP. Methods: Seven women, all healthy young participants, with no histories of thrombotic disorders and not on medications, were tested in two phases of the menstrual cycle (early follicular (EF) and mid-luteal (ML)). LBNP was commenced at −10 mmHg and increased by −10 mmHg every 5 min until a maximum of −40 mmHg. Recovery up to 10 min was also monitored. Blood samples were collected at baseline, at end of LBNP, and at end of recovery. Hemostatic profiling included comparing the effects of LBNP on coagulation values in both phases of the menstrual cycle using standard coagulation tests, calibrated automated thrombogram, thrombelastometry, impedance aggregometry, and markers of thrombin formation. Results: LBNP led to coagulation activation determined in both plasma and WB samples. During both phases, coagulation was affected during LBNP, as reflected in their decreased partial thromboplastin time (PTT) and elevated coagulation factor VIII FVIII, F1 + 2, and thrombin-antithrombin (TAT) levels. Additionally, during the ML phase, greater PT [%] and shorter time to peak (ttPeak) values (implying faster maximum thrombin formation) suggest that women in the ML phase are relatively hypercoagulable compared to the early follicular phase. Conclusions: These results suggest that thrombosis occurs more during the midluteal phase, a finding with substantial medical implications.

Potential Racial Disparity In Peripheral Vascular Function Regardless Of Menstrual Cycle Phase

African American women (AAW) have the highest rates of cardiovascular disease (CVD) across the lifespan compared to women of other races. Vascular dysfunction is a non-traditional risk factor for CVD and is understudied in AAW. Previous studies have reported fluctuations in vascular function across the menstrual cycle (MC) with the changing levels of estrogen, but this relation has never been explored in the context of race. PURPOSE: To compare nitric oxide-mediated peripheral vascular function across 3 phases of the MC between AAW and CW using passive leg movement (PLM). METHODS: PLM was performed on premenopausal, healthy, female participants not using hormonal contraceptives; 7 AAW (24 ±2 years, BMI: 21.2 ±1.4 kg/m2, BP: 112 ±3/74 ±3 mmHg) and 12 CW (23 ±1 years, BMI: 23.4 ±0.9 kg/m2, BP: 113 ±2/70 ±2 mmHg). Phases of the MC were identified as early follicular (EF) (1-5 days post onset of menstruation; low estrogen), ovulation (OV) (within 1-3 days of luteinizing hormone surge determined by an ovulation test; high estrogen), and mid-luteal (ML) (8-10 days post ovulation; moderate estrogen). Blood velocity and diameter of the femoral artery were measured using Doppler ultrasound. A 2x3 repeated measures ANOVA was used to identify differences in vascular function between AAW and CW across 3 phases of the MC. RESULTS: The overall change in leg blood flow from baseline to peak (mL) was significantly lower among AAW compared to CW across the MC phases. EF (AAW: 195 ±49, CW: 356 ±64), OV (AAW: 156 ±47, CW: 451 ±102) and ML (AAW: 224 ±65, CW: 369 ±41) (p=0.02).The hyperemic response to PLM, calculated as area under the curve (mL), was significantly reduced in AAW compared to CW across the MC phases. EF (AAW: 45 ±21, CW: 131 ±40), OV (AAW: 49 ±28, CW: 144 ±40) and ML (AAW: 67 ±22, CW: 130 ±26) (p=0.03). CONCLUSION: AAW are experiencing an attenuated peripheral vascular response to PLM compared to CW across the menstrual phases. These preliminary data suggest an overall race-derived disparity in peripheral vascular function regardless of MC phase in young premenopausal women.

Aerobic Exercise Performance is Reduced in the Mid‐luteal Compared to the Mid‐follicular Phase of the Menstrual Cycle in Eumenorrheic Women

PurposeUp to 40% of women believe their menstrual cycle affects their aerobic exercise performance. Fluctuations in sex hormone concentrations heighten many physiological and psychological responses to aerobic exercise in the mid‐luteal (ML) compared to the mid‐follicular (MF) phase of the menstrual cycle, which can promote reductions in aerobic exercise performance in the ML phase. However, the literature is equivocal regarding whether aerobic exercise performance differs between the ML and MF phases. Therefore, we tested the hypothesis that aerobic exercise performance is impaired in the ML compared to the MF phase of the menstrual cycle.MethodsTwelve recreationally active eumenorrheic women (25 ± 6 y) completed three familiarization and two experimental exercise sessions across the span of 3 consecutive menstrual cycles during the MF and ML phases. Saliva samples were collected at the beginning of each test session for analysis of progesterone and estrogen concentration. Each exercise session consisted an 8 km time trial that was preceded by 5 min of constant load exercise at a power output both 10% below (88 ± 19 W) and 10% above (108 ± 19 W) the gas exchange threshold (GET). Total mood disturbance was calculated from the Profile of Mood States administered prior to exercise. Heart rate, ventilation, and oxygen uptake were continuously recorded throughout exercise. Ratings of perceived exertion (RPE) and ratings of fatigue were assessed during the time trial using visual analogue scales.ResultsProgesterone concentration was 250± 386 pg/ml higher in the ML phase compared to the MF phase (P = 0.04), while estrogen concentration did not differ between phases (4.1 ± 1.6 vs. 5.7 ± 1.6 pg/ml, P = 0.32). Total mood disturbance was greater during the ML compared with the MF phase (123 ± 19 vs. 112 ± 22 a.u., P = 0.03) indicating a more negative mood state during the ML phase. During constant load exercise 10% below GET, ventilation (38.2 ± 5.0 vs. 35.4 ± 4.7 L/min, P = 0.03) and oxygen uptake (1.4 ± 0.2 vs. 1.3 ± 0.2 L/min, P = 0.03) were higher during the ML phase, but heart rate did not differ between phases (P = 0.67). Ventilation (P =0.11), oxygen uptake (P = 0.23), and heart rate (P =0.50) did not differ between phases during exercise at 10% above GET. Mean power output was lower during the ML phase (115 ± 28 vs. 125 ± 27 W, P<0.01) which led to a slower time trial in the ML phase (18.3 ± 2.0 min) compared to the MF phase (17.8 ± 1.7 min, P=0.03). Ratings of fatigue were greater during the ML phase from 4–8 km (P ≤0.05), while RPE did not differ between phases (P = 0.09). Heart rate (P = 0.85), ventilation (P = 0.53), and oxygen uptake (P = 0.32) did not differ between phases during the time trial.ConclusionAerobic exercise performance is reduced in the ML phase compared to the MF phase of the menstrual cycle in recreationally active eumenorrheic women. This is likely explained by a negative mood state pre‐exercise in the ML phase along with increased ratings of fatigue that persisted during the self‐paced exercise.

Cerebral Blood Flow in the Internal Carotid Artery Throughout the Menstrual Cycle in Young, Healthy Women

BackgroundPrevious reports suggest female sex hormones may affect cerebral blood flow and cerebral flow velocity in women. The purpose of this study was to examine whether changes in cerebral blood flow occur throughout the menstrual cycle phases that are associated with fluctuations in sex hormones in young, healthy women.MethodsA subset of eight female participants (mean age 25 yrs) from our previously published study (Favre & Serrador, 2019) underwent one minute of supine steady‐state cerebral blood flow measurements in the internal carotid artery. Women were studied at three different time points across the menstrual cycle: the early‐follicular (EF) phase associated with low levels of estrogen and progesterone, the late‐follicular (LF) phase associated with high levels of estrogen and low levels of progesterone, and the mid‐luteal (ML) phase associated with high levels of both estrogen and progesterone. Cerebral blood flow in the internal carotid artery was measured using duplex ultrasonography. Beat‐by‐beat blood pressure, end‐tidal CO2, ECG, and middle cerebral flow velocity (MCAv) using transcranial Doppler ultrasonography were also obtained.ResultsThere were no statistically significant changes (P=0.269) in internal carotid blood flow across the menstrual cycle phases (EF=203.9±42.2, LF=227.0±53.7, ML=203.2±47.8 ml/min). When examined as a percent of flow from the early follicular phase, there were also no significant changes (P=0.207) across the menstrual cycle (EF=100.0±0.0, LF=111.6±14.5, ML=100.8±17.0 %). Additionally, there were no significant changes (P=0.488) in MCAv (EF=84.7±19.9, LF=89.5±21.2, ML=87.9±24.1 cm/s). End‐tidal CO2 significantly decreased (P=0.025) during the mid‐luteal phase compared to the late follicular phase (EF=38.0±3.0, LF=39.3±2.8, ML=37.0±3.1 mmHg). There were no significant changes (P=0.174) in internal carotid velocity (EF=41.5±7.0, LF=44.8±7.7, ML=40.1±9.2 cm/s) or internal carotid diameter (P=0.327) across the menstrual cycle phases (EF=0.45±0.02, LF=0.46±0.03, ML=0.46±0.01 cm).ConclusionAlthough we did not observe statistically significant changes in internal carotid blood flow across the menstrual cycle phases, we recognize that women demonstrated a 11% increase in flow during the late follicular phase, corresponding to a large effect size (Partial Eta Squared= 0.201). Because of our small sample size, we cannot rule out the possibility that the fluctuations in female sex hormones affect cerebral blood flow. Additionally, it is possible that the decreased end‐tidal CO2 in the mid‐luteal phase hid an underlying increase in cerebral blood flow. However, a larger sample of women is needed to conclude whether cerebral blood flow is affected throughout the menstrual cycle phases.Support or Funding InformationThis work was supported by the Pharmacology, Physiology and Neuroscience Department at Rutgers Biomedical and Health Sciences.

Menstrual cycle phase does not affect whole body peak fat oxidation rate during a graded exercise test.

Female sex hormones fluctuate in a predictable manner throughout the menstrual cycle in eumenorrheic women. In studies conducted in both animal and humans, estrogen and progesterone have been found to exert individual metabolic effects during both rest and exercise, suggesting that estrogen may cause an increase in fat oxidation during exercise. However, not all studies find these metabolic changes with the natural physiological variation in the sex hormones. To date, no studies have investigated whether whole body peak fat oxidation rate (PFO) and maximal fat oxidation intensity (FATmax) are affected at different time points [mid-follicular (MF), late-follicular (LF), and mid-luteal (ML)] in the menstrual cycle, where plasma estrogen and progesterone are either at their minimum or maximum. We hypothesized that an increased plasma estrogen concentration together with low progesterone concentration in LF would result in a modest but significant increase in PFO. We found no differences in body weight, body composition, or peak oxygen uptake (V̇o2peak) between any of the menstrual phases in the 19 healthy, young eumenorrheic women included in this study. PFO [MF: 0.379 (0.324-0.433) g/min; LF: 0.375 (0.329-0.421) g/min; ML: 0.382 (0.337-0.442) g/min; mean ± (95% CI)] and resting plasma free fatty acid concentrations [MF: 392 (293-492) µmol/l; LF: 477 (324-631) µmol/l; ML: 396 (285-508) µmol/L] were also similar across the menstrual cycle phases. Contrary to our hypothesis, we conclude that the naturally occurring fluctuations in the sex hormones estrogen and progesterone do not affect the whole body PFO and FATmax in young eumenorrheic women measured during a graded exercise test.NEW & NOTEWORTHY Menstrual cycle phase does not affect the peak fat oxidation rate during a graded exercise test. Natural physiological fluctuations in estrogen do not increase peak fat oxidation rate. FATmax is not influenced by menstrual cycle phase in healthy, young eumenorrheic women.

The effect of the menstrual cycle on running economy.

The aim of this study was to examine the effect of the menstrual cycle on running economy (RE). Using a repeated-measures design, ten eumenorrheic, trained female runners (age: 32±6 yrs, V̇O2max: 59.7±4.7 mL·kg-1·min-1) completed four, weekly, identical sub-maximal and maximal incremental step tests on a treadmill to measure physiological responses across a full menstrual cycle. For phase comparison, the results from the trials that fell in the early follicular (low estrogen, low progesterone), late follicular (high estrogen, low progesterone) and mid-luteal (high estrogen, high progesterone) phases were used. There was a significant effect of menstrual cycle phase on RE (P=0.001), with RE in the mid-luteal (ML) phase being worse than that of the early follicular (EF) (+2.33 mL·kg-1·min-1; P=0.026) and late follicular (LF) (+2.17 mL·kg-1·min-1; P=0.011) phases. The ML phase also resulted in elevated core temperature versus the EF (+0.51 ºC; P=0.001) and LF (+0.66 ºC; P=0.037) phases, and elevated minute ventilation versus the EF phase (+3.83 L·min-1; P=0.003). No significant effects of menstrual cycle phase were found on body mass, heart rate, ratings of perceived exertion, time-to-exhaustion, maximal oxygen consumption, or blood lactate concentration. In the ML phase, which causes increased core temperature and minute ventilation, RE is impaired at exercise intensities that are applicable to training and performance. In physiologically stressful environments, this impairment in RE may have a significant impact on training and performance.

Blood pressure and limb blood flow responses during hyperpnoea are not affected by menstrual cycle phase in young women

The purpose of this study was to clarify whether the menstrual cycle affects the cardiovascular and limb blood flow responses during hyperpnoea. Fifteen young female subjects participated. An incremental respiratory endurance test was performed at the early follicular (EF) and midluteal (ML) phases. Target minute ventilation was initially set at 30 % of maximal voluntary ventilation (MVV12) and was increased by 10 %MVV12 every 3 min. The test was terminated when the subjects no longer maintained the target ventilation. Mean arterial blood pressure (MBP) and mean blood flow in the brachial artery were continuously measured. There were no significant differences in the increase in MBP (EF: +13.0 ± 7.9 mmHg vs. ML: + 15.4 ± 12.9 mmHg during the test, F = 0.70, P = 0.59) and the decrease in brachial blood flow between the phases. These results suggest that menstrual cycle does not affect respiratory muscle-induced metaboreflex in young women.

The effect of menstrual cycle on maximal breath-hold time

This study investigated the effect of menstrual cycle phase on breath-hold time (BHT). Twelve healthy females, aged 18–30 yrs, with regular menstrual cycles, without breath-hold (BH) experience, performed a BH protocol which included eight repeated maximal efforts with face immersion in cool water separated by 2-min intervals in two different phases of menstrual cycle; early follicular (EF) phase and midluteal (ML) phase. Respiratory, cardiovascular and hematological responses were studied before, during and after BH efforts. Maximal BHT was significantly higher during ML (115.59 ± 13.95 s) compared to EF (106.10 ± 12.42 s) phase of the menstrual cycle. Metabolic rate and build-up of CO2 were higher (p < 0.001) in EF compared to ML phase. In conclusion, the greater BHT observed at the ML phase of the menstrual cycle may be the result of elevated levels of estrogen and progesterone during midluteal phase affecting both ventilatory response and metabolic rate.

Sex difference or hormonal difference in mental rotation? The influence of ovarian milieu

Sex differences in visuospatial cognition have long been reported, with men being advantaged on the Mental Rotations Test (MRT). The data, however, are variable, and sensitive to design parameters. When men and women are compared directly, with women in different hormonal milieus combined, there seem to be sex differences. When women alone are studied, taking into account different ovarian steroid concentrations and treatments, MRT performance varies with these changes. Indeed, several reports describe better performance among women with reduced estrogens. To better understand whether the sex difference in MRT persists once hormonal status is considered, we recruited reproductive age adults designated male and female at birth (MAB, FAB), and administered the Vandenberg-Kuse (V/K) MRT—comparing performance among MAB (n = 169) and FAB (n = 219). For FAB combined, we found a sex difference with MAB performing better than FAB. However, when FAB were analyzed by current menstrual cycle phase (Early Follicular (EF), Periovulatory (PO), Midluteal (ML)) or by hormone therapy (transmasculine testosterone administration (TM+), oral contraceptive (OC) ingestion prior to (OC+) or after cognitive testing (OC-)), low-estradiol groups (EF, OC-, TM+) performed as strongly as MAB, and had better MRT than cycling FAB in high-estradiol menstrual cycle phases (PO, ML). On a verbal memory control task, neither a sex difference nor a low estrogen advantage was detected, although performance varied with hormonal milieu. Our findings support a dynamic model of spatial performance and suggest that both MAB and FAB perform strongly on MRT, contingent on hormonal status.

Ergogenic effects of caffeine on peak aerobic cycling power during the menstrual cycle.

Recent investigations have established that the ingestion of a moderate dose of caffeine (3-6mgkg-1) can increase exercise and sports performance in women. However, it is unknown whether the ergogenicity of caffeine is similar during all phases of the menstrual cycle. The aim of this investigation was to determine the ergogenic effects of caffeine in three phases of the menstrual cycle. Thirteen well-trained eumenorrheic triathletes (age = 31 ± 6years; body mass = 58.6 ± 7.8kg) participated in a double-blind, cross-over, randomised experimental trial. In the (1) early follicular (EF); (2) preovulation (PO); (3) and mid luteal (ML) phases, participants either ingested a placebo (cellulose) or 3mgkg-1 of caffeine in an opaque and unidentifiable capsule. After a 60-min wait for substance absorption, participants performed an incremental maximal cycle ergometer test until volitional fatigue (25W/min) to assess peak aerobic cycling power (Wmax). In comparison to the placebo, caffeine increased Wmax in the EF (4.13 ± 0.69 vs. 4.24 ± 0.71W kg-1, Δ = 2.7 ± 3.3%, P = 0.01), in the PO (4.14 ± 0.70 vs. 4.27 ± 0.73W kg-1, Δ = 3.3 ± 5.0%; P = 0.03) and in the ML (4.15 ± 0.69 vs. 4.29 ± 0.67W kg-1, Δ = 3.6 ± 5.1%; P = 0.01) phases. The magnitude of the caffeine ergogenic effect was similar during all of the menstrual cycle phases (P = 0.85). Caffeine increased peak aerobic cycling power in the early follicular, preovulatory, and mid luteal phases. Thus, the ingestion of 3mg of caffeine per kg of body mass might be considered an ergogenic aid for eumenorrheic women during all three phases of the menstrual cycle.

Influence of Peak Menstrual Cycle Hormonal Changes on Restoration of Fluid Balance After Induced Dehydration.

The present study examined the impact of hormonal differences between late follicular (LF) and midluteal (ML) phases on restoration of fluid balance following dehydration. Ten eumenorrheic female participants were dehydrated by 2% of their body mass through overnight fluid restriction followed by exercise-heat stress. Trials were undertaken during the LF (between Days 10 and 13 of the menstrual cycle) and ML phases (between Days 18 and 23 of the menstrual cycle) with one phase repeated to assess reliability of observations. Following dehydration, participants ingested a volume equivalent to 100% of mass loss of a commercially available sports drink in four equal volumes over 30min. Mean serum values for steroid hormones during the ML (estradiol [E2]: 92 ± 11pg/ml, progesterone: 19 ± 4ng/ml) and LF (estradiol [E2]: 232 ± 64pg/ml, progesterone: 3 ± 2ng/ml) were significantly different between phases. Urine tests confirmed no luteinizing hormone surge evident during LF trials. There was no effect of menstrual cycle phase on cumulative urine volume during the 3-hr rehydration period (ML: 630 [197-935]ml, LF: 649 [180-845]ml) with percentage of fluid retained being 47% (33-85)% on ML and 46% (37-89)% on LF (p = .29). There was no association between the progesterone:estradiol ratio and fluid retained in either phase. Net fluid balance, urine osmolality, and thirst intensity were not different between phases. No differences in sodium (ML: -61 [-36 to -131]mmol, LF: -73 [-5 to -118]mmol; p = .45) or potassium (ML: -36 [-11 to -80]mmol, LF: -30 [-19 to -89]mmol; p = .96) balance were observed. Fluid replacement after dehydration does not appear to be affected by normal hormonal fluctuations during the menstrual cycle in eumenorrheic young women.

Expression of Kisspeptin and its receptor in the hypothalamus of cyclic and acyclic buffalo (Bubalus bubalis)

Kisspeptin (Kiss1), neurokinin-B (NKB) and dynorphin (Dyn) neurons regulate the surge and pulsatile centres of gonadotropin releasing hormone (GnRH) in the hypothalamus and are modulated by the ovarian steroids. Accordingly, we studied the temporospatial expression of Kiss1, its receptor and other genes that regulate GnRH in the preoptic area (POA) and arcuate (ARC) regions of hypothalamus at different phases of bubaline estrous cycle. Brain of buffalo (n = 32) was collected immediately after exsanguination and categorized into early luteal (EL), mid luteal (ML), follicular (FL) stages and acyclic (n = 8/group). Total RNA was extracted from the POA and ARC of each stage and real time PCR amplification of Kiss1, Kiss1r, NKB, NKB receptor (NKBR), Dyn, Dyn receptor (OPRK1), GnRH1, ERα, PR, LEPR and GHSR was done using GAPDH as endogenous control and acyclic stage as calibrator group. Further, immunolocalization of Kiss1 and Kiss1r was done on the hypothalamus. In the POA, significant up-regulation of Kiss1 and NKB with a concomitant down-regulation of Dyn transcripts was recorded at FL stage. There was, however, down-regulation of Kiss1 and Kiss1r during the EL perhaps due to the loss of estradiol as a consequence of ovulation. On the other hand, in the ARC, there was a significant up-regulation of Kiss1 and Dyn at FL and ML, while NKB transcript was consistently down-regulated at any stage of estrous cycle. In the POA, expression of ERα was not modulated; however, PR was down-regulated in the EL. In the ARC, the ERα expression was significantly up-regulated in the EL, whereas, PR was moderately expressed irrespective of the stage of estrous cycle. The immunolocalization study revealed the presence of Kiss1 and Kiss1r in the POA and ARC in the cyclic buffalo with relative abundance at FL. The transcriptional profile of the genes suggests that there is estrous cycle stage specific expression of Kiss1, Kiss1r and other GnRH regulating genes in the POA and ARC regions of hypothalamus in the buffalo. Up-regulation of Kiss1r in the POA during ML and ARC during EL indicates the involvement of kisspeptinergic system in the regulation of low LH pulse frequencies during the early and mid luteal phases in the cyclic buffalo.

Blood Pressure Response during Combined Inspiratory Loading and Subsytolic Circulatory Occlusion during Exercise: Effects of Sex and Menstrual Cycle

Locomotor and respiratory muscle feedback via group III/IV afferents influences the blood pressure response during exercise. Specifically, stimulation of the inspiratory and locomotor muscle afferents (via inspiratory loading (IL) and subsystolic circulatory occlusion (CUFF), respectively) increases the blood pressure response during exercise with combined IL and CUFF (IL+CUFF) further augmenting the blood pressure response. Sex differences in blood pressure have been observed in both IL and CUFF when investigated individually, while the influence of sex hormones is unclear. It is unknown if sex and menstrual cycle phase influences the blood pressure response to IL+CUFF during exercise.PurposeTo determine if sex and menstrual cycle phase influence the blood pressure response during IL+CUFF in men and premenopausal women. We hypothesized that women will exhibit attenuated increases in blood pressure compared to age‐matched men during IL, CUFF, and IL+CUFF, while no differences would be present across the menstrual cycle.MethodsTo date, 13 adults (7M/6W; M: 28±6 vs. W: 29±4 yrs, p=0.30; M: 27±5 vs. W: 25±2 kg/m2, p=0.85) have participated in this study. Participants performed four 10 min exercise bouts at 40% of their peak oxygen uptake. The participants performed spontaneously breathing (SB) during the first 5 minutes and voluntary hyperventilation (i.e. breathing frequency of 40 breaths/min with 50% duty cycle) during the last 5 minutes. During this last 5 min, IL (30% maximal inspiratory pressure), CUFF (80 mmHg), IL + CUFF, or no intervention (CTL) occurred in a randomized order. Women completed the study protocol twice, once during midluteal (ML) phase and once during early follicular (EF) phase. Blood pressure was measured using manual sphygmomanometry. Changes in systolic blood pressure (ΔSBP), diastolic blood pressure (ΔDBP), and mean arterial pressure (ΔMAP) were determined by subtracting values obtained during IL, CUFF, IL+CUFF, or CTL from SB.ResultsThere were no significant differences in ΔMAP across groups during CTL (M: 5±5; ML 2±2; EF: 2±2 mmHg, all p&gt;0.24), IL (M: 11±4; ML 10±2; EF 12±5 mmHg, all p&gt;0.60), CUFF (M: 19±6; ML 16±4; EF 20±2 mmHg, all p&gt;0.20), or IL + CUFF (M: 24±5; ML 23±6; EF 23±3 mmHg, all p&gt;0.82). There were no significant differences in ΔSBP across groups during CTL (M: 5±4; ML 5±4; EF: 8±13 mmHg, all p&gt;0.49), IL (M: 17±6; ML 17±5; EF 19±8 mmHg, all p&gt;0.63), CUFF (M: 24±12; ML 23±7; EF 28±5 mmHg, all p&gt;0.31), or IL + CUFF (M: 34±8; ML 33±11; EF 33±8 mmHg, all p&gt;0.94). There were no significant differences in ΔDBP across group during CTL (M: 5±8; ML 0±1; EF: −1±4 mmHg, all p&gt;0.05), IL (M: 8±3; ML 7±2; EF 9±4 mmHg, all p&gt;0.71), CUFF (M: 16±4; ML 13±4; EF 16±2 mmHg, all p&gt;0.20), or IL + CUFF (M: 19±6; ML 18±6; EF 18±3 mmHg, all p&gt;0.75).ConclusionWith this limited sample size, our data suggest that neither sex nor menstrual cycle phase influences the blood pressure response with IL, CUFF or IL+CUFF.Support or Funding InformationNIH HL126638AHA 18POST3990251This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Changes in Biochemical Profile of Superovulated Sahiwal Cows through Hormonal Manipulation at Mid Luteal Phase of Estrous Cycle

Changes in Biochemical Profile of Superovulated Sahiwal Cows through Hormonal Manipulation at Mid Luteal Phase of Estrous Cycle

Effectiveness of Fish Oil Supplementation in Attenuating Exercise-Induced Muscle Damage in Women During Midfollicular and Midluteal Menstrual Phases.

McKinley-Barnard, SK, Andre, TL, Gann, JJ, Hwang, PS, and Willoughby, DS. Effectiveness of fish oil supplementation in attenuating exercise-induced muscle damage in females during midfollicular and midluteal menstrual phases. J Strength Cond Res 32(6): 1601-1612, 2018-The purpose of this study was to determine whether the differences in estrogen levels during the female menstrual cycle and fish oil supplementation would attenuate eccentric exercise-induced muscle damage and delayed-onset muscle soreness (DOMS). In a double-blind fashion, 22 physically active females (20.9 ± 1.4 years, 63.5 ± 9.0 kg, 165.2 ± 7.5 cm) were randomly assigned to ingest either 6 g of fish oil (n = 11) or placebo (n = 11) daily for 21 days. Participants underwent an eccentric exercise bout of the knee extensors on 2 occasions during the midfollicular (MF) and midluteal (ML) phases of the 28-day menstrual cycle. Before (PRE), at 6 (6HRPOST), and at 24 hours postexercise (24HRPOST) for each session, participants underwent assessments of DOMS, muscle strength, and had venous blood samples and muscle biopsies obtained. Data were analyzed using a 2 × 2 × 3 repeated-measures multivariate analysis of variance for each criterion variable (p ≤ 0.05). Further analysis of the main effects for the test was performed using separate 1-way analyses of variance. Delayed-onset muscle soreness was significantly greater at the 6HRPOST and 24HRPOST timepoints compared with PRE (p < 0.001). Superoxide dismutase and tumor necrosis factor-alpha (TNF-α) concentrations were significantly higher at the MF phase compared with the ML phase (p < 0.001 and p = 0.05, respectively). There were no statistically significant differences observed for muscle strength, myoglobin, NF-Kβ p50, or NF-Kβ p65. This study demonstrates that higher levels of estrogen may exert a cytoprotective effect on the sarcolemma.

Influence of menstrual phase and arid vs. humid heat stress on autonomic and behavioural thermoregulation during exercise in trained but unacclimated women.

Despite an attenuated fluctuation in ovarian hormone concentrations in well-trained women, one in two of such women believe their menstrual cycle negatively impacts training and performance. Forthcoming large international events will expose female athletes to hot environments, and studies evaluating aerobic exercise performance in such environments across the menstrual cycle are sparse, with mixed findings. We have identified that autonomic heat loss responses at rest and during fixed-intensity exercise in well-trained women are not affected by menstrual cycle phase, but differ between dry and humid heat. Furthermore, exercise performance is not different across the menstrual cycle, yet is lower in humid heat, in conjunction with reduced evaporative cooling. Menstrual cycle phase does not appear to affect exercise performance in the heat in well-trained women, but humidity impairs performance, probably due to reduced evaporative power. We studied thermoregulatory responses of ten well-trained [V̇O2 max , 57 (7) ml min-1 kg-1 ] eumenorrheic women exercising in dry and humid heat, across their menstrual cycle. They completed four trials, each of resting and cycling at fixed intensities (125 and 150W), to assess autonomic regulation, then self-paced intensity (30min work trial), to assess behavioural regulation. Trials were in early-follicular (EF) and mid-luteal (ML) phases in dry (DRY) and humid (HUM) heat matched for wet bulb globe temperature (WBGT, 27°C). During rest and fixed-intensity exercise, rectal temperature was ∼0.2°C higher in ML than EF (P<0.01) independent of environment (P = 0.66). Mean skin temperature did not differ between menstrual phases (P ≥ 0.13) but was higher in DRY than HUM (P<0.01). Local sweat rate and/or forearm blood flow differed as a function of menstrual phase and environment (interaction: P≤0.01). Exercise performance did not differ between phases [EF: 257 (37), ML: 255 (43)kJ, P = 0.62], but was 7 (9)% higher in DRY than HUM [263 (39), 248 (40)kJ; P<0.01] in conjunction with equivalent autonomic regulation and thermal strain but higher evaporative cooling [16 (6)Wm2 ; P<0.01]. In well-trained women exercising in the heat: (1) menstrual phase did not affect performance, (2) humidity impaired performance due to reduced evaporative cooling despite matched WBGT and (3) behavioural responses nullified thermodynamic and autonomic differences associated with menstrual phase and dry vs. humid heat.

Mineralocorticoid receptor haplotype moderates the effects of oral contraceptives and menstrual cycle on emotional information processing.

The processing of emotional information is affected by menstrual cycle phase and by the use of oral contraceptives (OCs). The stress hormone cortisol is known to affect emotional information processing via the limbic mineralocorticoid receptor (MR). We investigated in an exploratory study whether the MR-genotype moderates the effect of both OC-use and menstrual cycle phase on emotional cognition. Healthy premenopausal volunteers (n=93) of West-European descent completed a battery of emotional cognition tests. Forty-nine participants were OC users and 44 naturally cycling, 21 of whom were tested in the early follicular (EF) and 23 in the mid-luteal (ML) phase of the menstrual cycle. In MR-haplotype 1/3 carriers, ML women gambled more than EF women when their risk to lose was relatively small. In MR-haplotype 2, ML women gambled more than EF women, regardless of their odds of winning. OC-users with MR-haplotype 1/3 recognised fewer facial expressions than ML women with MR-haplotype 1/3. MR-haplotype 1/3 carriers may be more sensitive to the influence of their female hormonal status. MR-haplotype 2 carriers showed more risky decision-making. As this may reflect optimistic expectations, this finding may support previous observations in female carriers of MR-haplotype 2 in a naturalistic cohort study.

The Influence of Menstrual Cycle and Androstadienone on Female Stress Reactions: An fMRI Study.

Communicating threats and stress via biological signaling is common in animals. In humans, androstadienone (ANDR), a synthetic male steroid, is a socially relevant chemosignal exhibited to increase positive mood and cortisol levels specifically in (periovulatory) females in positively arousing contexts. In a negative context, we expected that such effects of ANDR could amplify social evaluative threat depending on the stress sensitivity, which differs between menstrual cycle phases. Therefore, this fMRI study aimed to examine psychosocial stress reactions on behavioral, hormonal and neural levels in 31 naturally cycling females, between 15 early follicular (EF) and 16 mid-luteal (ML) females tested with ANDR and placebo treatment in a repeated-measures design. Regardless of odor stimulation, psychosocial stress (i.e., mental arithmetic task with social evaluative threat) led to elevated negative mood and anxiety in all females. A negative association of social threat related amygdala activation and competence ratings appeared in ML-females, indicating enhanced threat processing by ANDR, particularly in ML-females who felt less competent early in the stress experience. Further, ML-females showed reduced performance and stronger stress-related hippocampus activation compared to EF-females under ANDR. Hippocampal activation in ML-females also correlated positively with post-stress subjective stress. Contrarily, such patterns were not observed in EF-females or under placebo in either group. Strikingly, unlike passive emotional processing, ANDR in a stressful context decreased cortisol concentration in all females. This points to a more complex interaction of ovarian/gonadal hormones in social threat processing and stress reactivity. Our findings suggest that ANDR enhanced initial evaluation of self-related social threat in ML-females. Female stress reactions are related to stress sensitivity through enhanced awareness and processing of social cues in a stressful context, with menstrual cycle phase being a critical factor.

The effect of menstrual cycle phase on exercise capacity measured by treadmill exercise test

The aim of this study was to explore the impact of the menstrual phases on exercise capacity parameters measured by a treadmill exercise test in sedentary premenaupausal women. Exercise capacity expressed in terms of metabolic equivalents (MET) and exercise duration was measured by performing treadmill exercise tests in 30 women (mean age: 29 ± 5.8 years) with regular menstrual cycles at two points during their menstrual cycles: the late-follicular (LF) phase and the mid-luteal (ML) phase. The exercise duration was significantly higher (P < 0.05), and the exercise capacity (in MET) tended to be higher (P = 0.075) in the ML phase than in the LF phase. These results suggested that the menstrual phases in sedentary women can have an influence on exercise capacity. These changes may be attributed to the relative changes in the female steroid hormones between the LF and the ML phases.

Neurovascular Coupling Across the Menstrual Cycle

Vascular function is modulated in response to the changing hormonal patterns of the menstrual cycle. Sex hormones may also act on non‐vascular cells regulating blood flow, including astrocytes and neurons, which may alter cerebral blood flow responses. However, the impact of menstrual phase on cerebral neurovascular coupling has not been investigated. We hypothesized that the visually evoked cerebral blood flow response would be higher in the mid‐luteal phase of the menstrual cycle, corresponding to elevated estrogen levels.Nine normally menstruating women (Age = 28 ± 6 yrs, BMI = 25 ± 4kg/m2) underwent a visual stimulation test in the early follicular (EF) and mid‐luteal (ML) phase of the menstrual cycle. Beat‐by‐beat mean arterial pressure (MAP) was derived using photoplethysmography (Finometer) and posterior cerebral artery blood flow velocity (PCAVP) was measured using transcranial Doppler ultrasound (Multigon).At rest, MAP (EF: 86.8 ± 7.4mmHg, ML: 87.7 ± 6.2mmHg, p=0.78) and cerebral blood flow (EF: 36.5 ± 5.5cm/s; ML: 37.6 ±11.3cm/s, p=0.80) were similar between phases. Further, the magnitude (EF: 25.0 ± 6.0%, ML: 26.5 ±8.5%, p=0.38) and the timing (EF: 12.0 ± 1.4s, ML: 11.8 ± 1.9s, p=0.78) of the cerebral blood flow response to visual stimulation was similar between phases.These data suggest that contrary to our hypothesis, neurovascular coupling assessed by visual stimulation was not different across the menstrual cycle. Supported by the University of Alberta ‐ Human Performance Scholarship Fund.