The Impact of Menstrual Cycle Phases on Cardiac Autonomic Nervous System Activity: An Observational Study Considering Lifestyle (Diet, Physical Activity, and Sleep) among Female College Students

An Obstructive Sleep Apnea - A Novel Public Health Threat

In patients with obstructive sleep apnea (OSA) during obstructive events, episodes of hypoxia and hypercapnia may modulate the autonomic nervous system (ANS) by increasing sympathetic tone and irritability, which contributes to sympathovagal imbalance and ultimately dysautonomia. Because OSA can alter ANS function through biochemical changes, we can assume that heart rate variability (HRV) will be altered in patients with OSA. Most studies show that in both the time and frequency domains, patients with OSA have higher sympathetic components and lower parasympathetic dominance than healthy controls. These results confirm autonomic dysfunction in these patients, but also provide new therapeutic directions. Respiratory methods that modulate ANS, e.g., cardiorespiratory biofeedback, could be beneficial for these patients. Heart rate variability assessment can be used as a tool to evaluate the effectiveness of OSA treatment due to its association with autonomic impairment.

Cognitive function evaluation in premenstrual syndrome during the follicular and luteal phases using near-infrared spectroscopy

Background

Many adult females experience periodic mental and physical symptoms associated with premenstrual syndrome (PMS). Diagnosis of PMS is generally based on self-reported symptoms over several menstrual cycles, but there are concerns about its accuracy and duration. It is well known that decreased cognitive function is one of the symptoms of PMS. Near-infrared spectroscopy (NIRS) is one of the methods for imaging brain activity, similar to magnetic resonance imaging (MRI), electroencephalography (EEG), and positron emission tomography (PET). NIRS has been used to assess cognitive function decline demonstrated by decline in brain activity. However, to the best of our knowledge, there have been no report characterizing brain activity pattern in females with PMS during the luteal and follicular phases separately.

Objective

We aimed to characterize the cognitive function of females with PMS during the follicular and luteal phases using NIRS.

Methods

The level of brain activity in the prefrontal cortex was detected with NIRS while PMS women were performing cognitive tasks. NIRS detected brain activity by measuring the oxy-hemoglobin and deoxy-hemoglobin levels. Participants were females between the ages of 20 and 25 with PMS (n = 11) and without PMS (n = 11). During the participants’ follicular and luteal phases, the participants were asked to perform the cognitive task; an N-back task (0-, 1-, and 2-back tasks), which is widely used for assessing cognitive function. We also calculated the oxyhemoglobin integral value during the N-back task using the NIRS signal; this value represented the total amount of change in cerebral oxyhemoglobin and the brain activation level.

Results

The correct response rate on the 2-back task was significantly lower during both the follicular and luteal phases in females with PMS compared to that in females without PMS (P = 0.01; P = 0.02, during the follicular and luteal phases, respectively). During the luteal phase, brain activation was significantly lower in participants with PMS than in that in females without PMS (P = 0.04). In addition, during the luteal phase, the participants with PMS also had higher negative mood than those without PMS.

Conclusion

The cognitive decline during the luteal phase in participants with PMS was detected by NIRS with significant differences from participants without PMS. The difference was observed only during the luteal phase, not in the follicular phase and were related to the increase in negative mood. These results may provide an objective method for diagnosing PMS based on brain activity. We believe that the use of instruments (e.g., NIRS, MRI, EEG … etc.) to detect cognitive function decline will lead to rapid and reliable diagnosis of PMS and premenstrual dysphoric disorder.

Birth, love, and fear: Physiological networks from pregnancy to parenthood

Pregnancy and childbirth are among the most dramatic physiological and emotional transformations of a lifetime. Despite their central importance to human survival, many gaps remain in our understanding of the temporal progression of and mechanisms underlying the transition to new parenthood. The goal of this paper is to outline the physiological and emotional development of the maternal-infant dyad from late pregnancy to the postpartum period, and to provide a framework to investigate this development using non-invasive timeseries. We focus on the interaction among neuroendocrine, emotional, and autonomic outputs in the context of late pregnancy, parturition, and post-partum. We then propose that coupled dynamics in these outputs can be leveraged to map both physiologic and pathologic pregnancy, parturition, and parenthood. This approach could address gaps in our knowledge and enable early detection or prediction of problems, with both personalized depth and broad population scale.

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Giving birth and caring for offspring are dynamic processes that can instill both love and fear.

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Maternal physiology continuously integrates fetal, social, and environmental cues.

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The result is coupled change in hormonal, autonomic nervous, and emotional output.

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Coupling may allow internal state to be assessed from peripheral autonomic markers.

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Such markers may identify healthy or pathologic pregnancy, parturition, and parenting, and enable creation of real-world tools.

Effect of Laboratory Mental Stressors on Cardiovascular Reactivity in Young Women During Different Phases of Menstrual Cycle: An Observational Study

Introduction: Excessive cardiovascular reactivity to mental stress may be a risk factor for cardiovascular disease. However, there is inconsistent report in the literature regarding change in cardiac autonomic tone with the phase of the menstrual cycle and how it is affected by mental stress. Therefore, the present study was aimed at determining the cardiovascular reactivity to different laboratory mental stressors during follicular and luteal phase of menstrual cycle using heart rate variability (HRV). Methods: Thirty-three regularly cycling young females (19-35 years of age) were exposed to four cognitive tasks (Stroop test, Mental Rotation test, n-back test, and Mental Arithmetic Stress Test [MAST]) employed as laboratory mental stressors. HRV of the study participants were recorded before, during, and after each cognitive task and the recording was done in both phases of menstrual cycle for each individual. Results: A significant difference was observed in time domain parameters and nonlinear parameters of HRV in pretest versus during-test condition and during-test versus post-test conditions, but not in frequency domain parameters. No phase difference was found in time domain or frequency domain analysis of HRV in baseline or during performance of task. MAST performance (score out of 50) was significantly higher in luteal than follicular phase, while other tests showed no such difference. Conclusion: All four mental stress tasks used in the present study were able to elicit significant decrease in parasympathetic tone during performance of task as compared with baseline values of HRV. The present study did not elicit any phase difference in cardiovascular reactivity.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach

Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18-40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Characterization of Reproductive and Morphological Variables in Female Elite Futsal Players

We aimed to characterize the age of onset of training, age at menarche, menstrual periodicity, and performance perception during the menstrual cycle and examined the impact of these reproductive variables on body composition, morphology, and body weight satisfaction in Brazilian elite futsal players. The study consisted of 115 female Brazilian elite futsal players from the top national teams. Data were collected during the twentieth Women's Brazil Futsal Cup. Players were interviewed and self-reported their age of onset of training, age at menarche, menstrual periodicity, and the menstrual period, where they performed best. We also asked for what they considered to be their ideal body weight as well as information related to their training (i.e., volume and frequency). Subsequently, anthropometric measurements (i.e., body mass, height, circumferences, diameters, and skinfold thickness) were performed to estimate the body composition and determine morphological characteristics (e.g., somatotype). Fifty-nine (53.2%) players were postmenarche-trained and 52 (46.8%) were premenarche-trained. Eighteen (16.2%), 65 (58.6%), and 28 (25.2%) were classified as early, normal, and late menarche, respectively. Only 11 (9.6%) and 1 (0.9%) had irregular menstrual cycles and were amenorrheic, respectively. Seventy-three (69.5%), 23 (21.9%), and 9 (8.6%) reported that their game performance was the best at the follicular phase, menses, and luteal phase of the menstrual cycle, respectively. No associations between the four reproductive-related variables were found. Postmenarche-trained players had significant lower age at menarche and higher percentage body fat. The somatotype profile registered lower ectomorphy rate for the postmenarche-trained participants after controlling for covariates. Early menarche group presented higher sum of six skinfold thickness and endomorphy rate compared to normal and late menarche groups. No differences were found when menstrual periodicity groups and best performance groups were compared, except for higher femur width in the regular menstrual cycle group compared to the irregular one. The association between body weight satisfaction and the four reproductive-related variables were not observed. Premenarche-trained Brazilian elite futsal players had the menarche later than the postmenarche-trained athletes. Most of the participants had menarche age classified as "normal," presented "regular" menstrual cycles and perceived to perform better during the follicular phase of the menstrual cycle.

Vascular Endothelial Dysfunction and Autonomic Nervous Hyperactivity among Premenopausal Women with Cold-Sensitivity Constitution (Hiesho)

The cold-sensitivity constitution (CSC), termed "Hiesho" in Japanese, is a woman-specific cold sense of peripheral sites. The etiology of and criteria for CSC are not yet well established. We defined CSC as temperature gradient > 6˚C between body surface and core, and investigated the autonomic nervous activity by measuring heart rate variability and the vascular endothelial function by determining reactive hyperemia index (RHI) in 43 healthy premenopausal women, aged 18-47 years. Twenty five women had CSC during both the follicular and luteal phases of their menstrual cycles (sustained-CSC group), 8 women did not show CSC during both phases (non-CSC group), and the remaining 10 women showed CSC in either menstrual phase (occasional CSC). To identify the pathophysiological bases of CSC, we compared the sympathetic nervous activity and vascular endothelial function between sustained-CSC and non-CSC. We thus found that sympathetic nervous activity was higher among the sustained-CSC group (p = 0.042) during the follicular phase, compared with the non-CSC group, while the RHI was similar in both groups. Furthermore, the sympathetic nervous activity was similar between the sustained-CSC women aged ≥ 40 years (n = 10) and those aged < 40 years (n = 15) during either menstrual phase, whereas the RHI of the women aged < 40 years was lower during the follicular phase (p = 0.045), compared with the women aged ≥ 40 years. In conclusion, CSC is associated with sympathetic nervous hyperactivity in premenopausal women, and vascular endothelial dysfunction is also involved in CSC among younger women.

Ultradian rhythms in heart rate variability and distal body temperature anticipate onset of the luteinizing hormone surge

The menstrual cycle is characterized by predictable patterns of physiological change across timescales. Although patterns of reproductive hormones across the menstrual cycle, particularly ultradian rhythms, are well described, monitoring these measures repeatedly to predict the preovulatory luteinizing hormone (LH) surge is not practical. In the present study, we explored whether non-invasive measures coupled to the reproductive system: high frequency distal body temperature (DBT), sleeping heart rate (HR), sleeping heart rate variability (HRV), and sleep timing, could be used to anticipate the preovulatory LH surge in women. To test this possibility, we used signal processing to examine these measures in 45 premenopausal and 10 perimenopausal cycles alongside dates of supra-surge threshold LH and menstruation. Additionally, urinary estradiol and progesterone metabolites were measured daily surrounding the LH surge in 20 cycles. Wavelet analysis revealed a consistent pattern of DBT and HRV ultradian rhythm (2-5 h) power that uniquely enabled anticipation of the LH surge at least 2 days prior to its onset in 100% of individuals. Together, the present findings reveal fluctuations in distal body temperature and heart rate variability that consistently anticipate the LH surge, suggesting that automated ultradian rhythm monitoring may provide a novel and convenient method for non-invasive fertility assessment.

Comparison of Linear and Nonlinear HRV Dynamics Across Exercise Intensities After Menopause

The authors compared the linear and nonlinear heart rate variability dynamics from rest through maximal exercise in postmenopausal women who trained at either moderate or high intensities. The outcome variables included the RR triangular index, TINN, SD1, SD2, SD1/SD2, DFA α1, DFA α2, and α1/α2. Maximal exercise reduced SD1, SD2, DFA α1, DFA α2, α1/α2, RRTri, and TINN in both groups and increased SD1/SD2 (p < .05). Two minutes of active recovery produced significant increases in SD1, SD2, DFA α1, and TINN, compared with exercise in both groups (p < .0001). There was also a significant main effect between groups for RRTri during exercise recovery, with the moderate group achieving higher levels (p < .04). The authors have shown that both moderate and vigorous exercise training can lead to a healthy response to maximal exercise and recovery, with the moderate group having a slightly improved recovery in the triangular index.

Heart rate variability in adults with obstructive sleep apnea: a systematic review

Obstructive Sleep Apnea is a common respiratory disorder characterized by recurrent nocturnal episodes of normal breathing interruption due to upper airway total or partial collapse. Obstructive sleep apnea and cardiovascular diseases has similar risk factors, but the first is also a predisposing factor for cardiovascular pathologies independently of individuals demographic characteristics or risk markers. Heart rate variability is a non-invasive method to evaluate the regulation of autonomic nervous system and its a promising marker for health and disease, such as cardiovascular and respiratory diseases. The aim was to review whether heart rate variability is altered in patients with obstructive sleep apnea. We searched in five databases, including BIREME, Cochrane, Scholar Google, MEDLINE/PubMed and Periodics CAPES, and reference lists were also searched. Only cross-sectional studies comparing the heart rate variability of obstructive sleep patients with controls were included. Two authors independently extracted data and assessed trial quality. Twelve studies (513 participants with obstructive sleep apnea and 340 controls) met the inclusion criteria. This review evidence that adults with obstructive sleep apnea may demonstrate diminished vagal tone and higher sympathetic responsiveness.

Effect of the menstrual cycle on circulation during combined spinal-epidural anaesthesia

Background

From adolescence to menopause, hormone levels during the menstrual cycle affect various body systems, from the cardiovascular system to the water and electrolyte balance. This study investigated the effect of different phases of the menstrual cycle on circulatory function relative to changes in body position and combined spinal-epidural anaesthesia (CSEA).

Methods

Forty-six women were selected who underwent scheduled gynaecological surgery, were classified as American Society of Anesthesiology (ASA) I-II, and met the test criteria. The sample was divided into the follicular and corpus luteal groups. Preoperative heart rate and blood pressure measurements were taken from the supine and standing positions. Heart rate measurements as well as systolic, diastolic, and mean blood pressure measurements were taken upon entering the operating room, at the beginning of the spinal-epidural anaesthesia, and 10, 20, and 30 min after anaesthesia was administered.

Results

The heart rates of patients in the corpus luteal group were higher than those of patients in the follicular group both before and after anaesthesia (P <  0.05). Significantly more ephedrine was used during the first 30 min of CSEA in the corpus luteal group than in the follicular group (P <  0.05).

Conclusions

Although the effect was slight, women in the follicular phase were better able to compensate and tolerate circulatory fluctuations than those in the luteal phase.

Effects of heart rate variability biofeedback training in athletes exposed to stress of university examinations

Introduction

Heart rate variability biofeedback (HRV-BFB) training, a method whereby one controls an unusually low breathing rate to reach cardiac coherence, has been shown to reduce anxiety and improve cardiac autonomic markers in diseased people, but much less is known about HRV-BFB benefits in healthy people. Here we investigated potential benefits in young competitors experiencing stress during university examinations as well as persistence of benefits after HRV-BFB training cessation.

Methods

A group of sports students (n = 12) practiced 5-min HRV-BFB training twice a day for 5-weeks using URGOfeel^® (URGOTECH) and was compared to a control group (n = 6). University examinations occurred immediately after HRV-BFB training (Exam1), then 12-weeks later (Exam2). Anxiety markers and cardiac autonomic markers were assessed at baseline, Exam1 and Exam2. Principal Component Analyses (PCA) that combined all these markers were computed at Exam1 and Exam2 to emphasize covariations.

Results

At Exam 1, immediately after HRV-BFB training cessation, the experimental group demonstrated greater autonomic markers but similar states of anxiety when compared to the Control group. Twelve weeks later at Exam2, autonomic markers were greater and anxiety scores were lesser among the experimental group. PCA highlighted covariations only within cardiac autonomic markers at Exam1. Rather, variations in cardiac markers were associated with anxiety markers at Exam2.

Conclusion

Short sessions of HRV-BFB training for a brief period of 5 weeks bring substantial benefits to autonomic markers and anxiety levels in young competitors. Here beneficial effects persisted for 12 weeks. Dissociated profiles of anxiety and cardiac autonomic adaptations shed new light on the role of the amygdala in heart-brain interactions after cardiac coherence training.

Higher energy intake at dinner decreases parasympathetic activity during nighttime sleep in menstruating women: A randomized controlled trial

BACKGROUND

Previous studies have found more frequent increases in dietary intake and nonrestorative nocturnal sleep during the luteal phase than in the follicular phase, but few studies have investigated how increased energy intake at dinner influences sleep by considering the correlation between female hormone and cardiac autonomic nervous system (ANS) activity. This study examined the effects of energy intake at dinner on ANS activity during nighttime sleep in order to evaluate restorative sleep in healthy women. We also examined whether ANS activity is associated with female hormone dynamics.

METHODS

Twenty-four healthy collegiate women participated in this randomized crossover trial. Each was assigned to receive a High Energy Dinner (HED) or Low Energy Dinner (LED) treatment. Energy ratios of each test meal (breakfast, lunch, and dinner) to total energy intake were 1:1:2 and 1:2:1 for HED and LED treatments, respectively. Each participant wore an ECG recorder before dinner and removed it upon waking the next morning. Power spectral analysis of heart rate variability was used to calculate low frequency (LF), high frequency (HF), and total spectral power (TP). Cardiac sympathetic (SNS) and parasympathetic (PNS) nervous system activity were evaluated as LF/HF and HF/TP, respectively.

RESULTS

Mean HF/TP for the entire sleeping period was lower with HED treatment compared to LED treatment (41.7 ± 11.4 vs. 45.0 ± 12.13, P = .034). Intergroup comparisons of the initial 3-h sleeping period revealed that LF/HF (0.87 ± 0.82 vs. 0.66 ± 0.82, P = .013) and HF/TP (45.6 ± 13.9 vs. 51.5 ± 11.8, P = .002) were higher and lower, respectively, with HED treatment compared to LED treatment. Progesterone levels were positively correlated with LF/HF with LED treatment, and negatively correlated with HF/TP with both HED and LED treatments.

CONCLUSION

Higher energy intake at dinner increases and decreases SNS and PNS activities, respectively, resulting in nonrestorative nocturnal sleep. In addition, a negative correlation was observed between progesterone and PNS activity, highlighting the difficulty of increasing PNS activity during sleep in the luteal phase compared to the follicular phase.

Sex Differences in Autonomic Cardiac Control and Oxygen Saturation Response to Short-Term Normobaric Hypoxia and Following Recovery: Effect of Aerobic Fitness

Introduction: The main aims of this study were to investigate autonomic nervous system (ANS) and arterial oxygen saturation (SpO₂) responses to simulated altitude in males and females, and to determine the association between maximal oxygen uptake (VO₂max) and these responses. Materials and Methods: Heart rate variability (HRV) and SpO₂ were monitored in a resting supine position during Preliminary (6 min normoxia), Hypoxia (10 min, fraction of inspired oxygen (FiO₂) of 9.6%, simulated altitude ~6,200 m) and Recovery (6 min normoxia) phases in 28 males (age 23.7 ± 1.7 years, normoxic VO₂max 59.0 ± 7.8 ml.kg^-1.min^-1, body mass index (BMI) 24.2 ± 2.1 kg.m^-2) and 30 females (age 23.8 ± 1.8 years, VO₂max 45.1 ± 8.7 ml.kg^-1.min^-1, BMI 21.8 ± 3.0 kg.m^-2). Spectral analysis of HRV quantified the ANS activity by means of low frequency (LF, 0.05-0.15 Hz) and high frequency (HF, 0.15-0.50 Hz) power, transformed by natural logarithm (Ln). Time domain analysis incorporated the square root of the mean of the squares of the successive differences (rMSSD). Results: There were no significant differences in SpO₂ level during hypoxia between the males (71.9 ± 7.5%) and females (70.8 ± 7.1%). Vagally-related HRV variables (Ln HF and Ln rMSSD) exhibited no significant differences between sexes across each phase. However, while the sexes demonstrated similar Ln LF/HF values during the Preliminary phase, the males (0.5 ± 1.3) had a relatively higher (p = 0.001) sympathetic activity compared to females (-0.6 ± 1.4) during the Hypoxia phase. Oxygen desaturation during resting hypoxia was significantly correlated with VO₂max in males (r = -0.45, p = 0.017) but not in females (r = 0.01, p = 0.952) and difference between regression lines were significant (p = 0.024). Conclusions: Despite similar oxygen desaturation levels, males exhibited a relatively higher sympathetic responses to hypoxia exposure compared with females. In addition, the SpO₂ response to resting hypoxia exposure was related to maximal aerobic capacity in males but not females.