The effect of stress on menstrual function

Free-living competitive racewalkers and runners with energy availability estimates of <35 kcal·kg fat-free mass-1·day-1 exhibit peak serum progesterone concentrations indicative of ovulatory disturbances: a pilot study

Introduction

The release of luteinising hormone (LH) before ovulation is disrupted during a state of low energy availability (EA). However, it remains unknown whether a threshold EA exists in athletic populations to trigger ovulatory disturbances (anovulation and luteal phase deficiency) as indicated by peak/mid-luteal serum progesterone concentration (Pk-PRG) during the menstrual cycle.

Methods

We assessed EA and Pk-PRG in 15 menstrual cycles to investigate the relationship between EA and Pk-PRG in free-living, competitive (trained-elite) Guatemalan racewalkers (n = 8) and runners (n = 7) [aged: 20 (14-41) years; post-menarche: 5 (2-26) years; height: 1.53 ± 0.09 m; mass: 49 ± 6 kg (41 ± 5 kg fat-free mass "FFM")]. EA was estimated over 7 consecutive days within the follicular phase using food, training, and physical activity diaries. A fasted blood sample was collected during the Pk-PRG period, 6-8 days after the LH peak, but before the final 2 days of each cycle. Serum progesterone concentration was quantified using electrochemiluminescence immunoassay.

Results

Participants that reported an EA of <35 kcal·kg FFM-1·day-1 (n = 7) exhibited ovulatory disturbances (Pk-PRG ≤9.40 ng·mL-1). Athletes with EA ≥36 kcal·kg FFM-1·day-1 (n = 8) recorded "normal"/"potentially fertile" cycles (Pk-PRG >9.40 ng·mL-1), except for a single racewalker with the lowest reported protein intake (1.1 g·kg body mass-1·day-1). EA was positively associated with Pk-PRG [r(9) = 0.79, 95% confidence interval (CI): 0.37-0.94; p = 0.003; 1 - β = 0.99] after excluding participants (n = 4) that likely under-reported/reduced their dietary intake.

Conclusions

The result from the linear regression analysis suggests that an EA ≥ 36 kcal·kg FFM-1·day-1 is required to achieve "normal ovulation." The threshold EA associated with ovulatory disturbances in athletes and non-invasive means of monitoring the ovulatory status warrant further research.

Neuroendocrine Blockade of the Reproductive Axis in Female Athletes

This review aims at defining the neuroendocrine mechanisms underlying the sport-induced restrictions of the reproductive axis in female athletes. Episodic gonadotropin release was found to be compromised, presumably a result of impaired hypothalamic pulsatile GnRH release. Any deviation from optimal gonadotropin release may result in a suboptimal function of the ovaries, leading to disorders of the menstrual cycle and ovulation. A whole spectrum of menstrual dysfunctions ranging from ovulatory eumenorrhea to luteal phase defects and amenorrhea has been reported in sportive women. As essential neuroendocrine factors underlying these observations, activation of the adrenal axis and altered central nervous neurotransmitter activity have been identified to transfer metabolic, nutritional, and stress signals into the hypothalamic GnRH release. The degree by which the neuroendocrine axis governing reproduction is impaired critically depends on the intensity and duration of exercise and the state of training. Other decisive factors may be energy expenditure and availability, nutritional components, and the maturity of the hypothalamic-pituitary-ovarian (HPO) axis when sport activity was initiated. In conclusion, the gradual cessation of reproductive function observed in female athletes may be interpreted as an adaptive mechanism in response to physical and psychological endurance during sport. This sport-induced restriction of reproductive capacity may serve as protection (endogenous contraception) to preserve a woman’s health.

Moderate Weight Loss is associated with Reductions in LH Pulse Frequency and Increases in 24-hour Cortisol with no change in Perceived Stress in Young Ovulatory Women

OBJECTIVE

Determine the potential role of cortisol as an indicator of both metabolic and psychosocial stress and its relation to LH pulse dynamics during a three-month diet and exercise intervention causing moderate weight loss.

METHODS

Secondary analysis of a randomized, controlled trial that demonstrated the causal role of low energy availability in the disruption of the menstrual cycle. Twenty-one women aged (18-24 yrs), BMI (21.7± 1.9 kg·m^-2), completed a baseline menstrual cycle and three intervention menstrual cycles of a controlled diet and supervised exercise program. Twenty-four-hour LH pulse dynamics (q10 min) and diurnal patterns of cortisol (q60 min) as well as Perceived Stress Scale scores were determined in the early follicular phase prior to the intervention and in the post intervention cycle. Pre to post comparisons were determined with paired t-tests, and Pearson bivariate correlations assessed associations.

RESULTS

Subjects lost weight (-2.8±1.97 kg) and LH pulse frequency declined pre=0.79±0.23 pulses·hr^-1 to post=0.60±0.29 pulses·hr^-1 (p=0.014). Weight loss was associated with an increase in cortisol AUC R=-0.473, (p=0.03) and the decline in LH pulse frequency R= 0.523; (p=0.026). Increases in cortisol AUC were associated with declines in LH pulse frequency R=-0.472; (p=0.048). The morning cortisol rise AUC increased from pre=2140±878 µg·dL^-1 · day to post=2556±1067 µg·dL^-1 · day (p=0.034). Changes in PSS were not associated with changes in LH or cortisol.

CONCLUSION

The initial perturbation of LH pulsatility with moderate diet and exercise is associated with metabolically driven increases in cortisol AUC with no influence of psychological stress.

Oyster peptide prevents the occurrence of exercise-hypogonadal male condition by improving the function of pituitary gonadal axis in male rats

This study evaluates the protective role of oyster peptide (OP) on the occurrence of Exercise-Hypogonadal Male Condition. Male rats were given heavy-load swimming training and / or OP was supplemented for 6 consecutive weeks. After heavy-load training, sperm count, sperm viability and sperm motility in epididymis, testosterone in serum and testis, glutathione peroxidase (GSH-px) and androgen receptor (AR) in testis and mating times were remarkably decreased, malondialdehyde (MDA), capture latency and mating latency were significantly increased, mRNA expression of steroidogenic acute regulatory (StAR) and P450 cholesterol side-chain cleavage enzyme (P450scc) were obviously down-regulated, but serum follicle-stimulating hormone (FSH) and luteinising hormone (LH) were not statistically changed. Conversely, when OP was supplemented at heavy-load training, sperm count, sperm viability and sperm motility in epididymis, serum FSH, LH, testosterone, GSH-px, superoxide dismutase (SOD), testosterone, AR in testis and mating times were dramatically increased, while testicular MDA, capture latency and mating latency were significantly decreased, and mRNA expression of StAR, StARD7, P450scc and 3β-hydroxysteroid dehydrogenase (3β-HSD) were significantly up-regulated. In conclusion, heavy-load training causes testicular spermatogenic and steroidogenic disorders by enhancing the generation of reactive oxygen species (ROS), which can be protected by the co-administration of OP by enhancing the function of pituitary gonad axis and lowering ROS generation.

Female Athlete Triad: Future Directions for Energy Availability and Eating Disorder Research and Practice

Despite more than 3 decades of research on the Female Athlete Triad, research gaps remain. Although low energy availability (EA) is the key etiologic factor in the Triad and the pathways to low EA are varied, its effects can be modified by several factors. Accurate screening, diagnosis, and treatment of disordered eating are a challenge; however, recent techniques combined with novel educational and behavior interventions prove promising. Recently published practice-based guidelines have helped to translate Triad science and should improve as they are refined. This article identifies the current state of research and distinguishes areas that require further investigation.

Neuroendocrine integration of nutritional signals on reproduction

Reproductive function in mammals is energetically costly and therefore tightly regulated by nutritional status. To enable this integration of metabolic and reproductive function, information regarding peripheral nutritional status must be relayed centrally to the gonadotropin-releasing hormone (GNRH) neurons that drive reproductive function. The metabolically relevant hormones leptin, insulin and ghrelin have been identified as key mediators of this 'metabolic control of fertility'. However, the neural circuitry through which they act to exert their control over GNRH drive remains incompletely understood. With the advent of Cre-LoxP technology, it has become possible to perform targeted gene-deletion and gene-rescue experiments and thus test the functional requirement and sufficiency, respectively, of discrete hormone-neuron signaling pathways in the metabolic control of reproductive function. This review discusses the findings from these investigations, and attempts to put them in context with what is known from clinical situations and wild-type animal models. What emerges from this discussion is clear evidence that the integration of nutritional signals on reproduction is complex and highly redundant, and therefore, surprisingly difficult to perturb. Consequently, the deletion of individual hormone-neuron signaling pathways often fails to cause reproductive phenotypes, despite strong evidence that the targeted pathway plays a role under normal physiological conditions. Although transgenic studies rarely reveal a critical role for discrete signaling pathways, they nevertheless prove to be a good strategy for identifying whether a targeted pathway is absolutely required, critically involved, sufficient or dispensable in the metabolic control of fertility.

Low energy availability and low body fat of female gymnasts before an international competition

The purpose of the present study was to evaluate dietary intake and body composition of elite rhythmic gymnastics (RG) athletes prior to a competition event. Sixty-seven rhythmic gymnasts (18.7 ± 2.9 years old) of high performance level, with 36.6 ± 7.6 h of training/week were evaluated in order to collect training and competition data, medical and gynaecological history, detailed dietary intake and body composition before an international competition. The majority of the participants (n = 40; 59.7%) had already menstruated, but age of menarche was delayed (15.3 ± 1.3 years) and all revealed menstrual irregularities. Gymnasts' body mass (48.4 ± 4.9 kg) and body mass index (BMI; 17.4 ± 1.1 kg/m(2)) were below the normal for age, and height (1.66 ± 0.05 m) was normal or even slightly above normal for age. Body fat was 9.0 ± 2.0% with no significant differences between age strata. Gymnasts exhibited low energy availability (EA; 31.5 ± 11.9 kcal/kg fat-free mass (FFM)/day). The average carbohydrate and protein intakes were 5.1 ± 2.3 g/kg/day and 1.6 ± 04 g/kg/day, which correspond to 51.4 ± 7.2% and 16.9 ± 3.4% of total energy intakes, respectively; average fat contribution was 33.0 ± 5.3%. Low intakes of pantothenic acid, folate and vitamins D, E and K and of minerals, including calcium, iron and magnesium were reported. Intakes of thiamine, riboflavin, niacin, vitamins A, B-6, B-12, C and manganese and zinc were above-adequate (P < 0.05). Low EA, low body fat and micronutrient deficiencies are common among RG.

Reproductive Dysfunction from the Stress of Exercise Training is not Gender Specific: The "Exercise-Hypogonadal Male Condition"

Investigative studies point to participation in exercise training as having significant detrimental effects upon reproductive hormonal profiles in men. Specifically, men chronically exposed to training for endurance sports exhibit persistently reduced basal (resting-state) free and total testosterone concentrations without concurrent LH elevations. Men displaying these symptoms have been deemed to exhibit the "Exercise-Hypogonadal Male Condition" (EHMC). The exact physiological mechanism inducing the reduction of testosterone in these men is currently unclear, but is postulated to be a dysfunction within the hypothalamic-pituitary-gonadal regulatory axis. The potential exists for the reduced testosterone concentrations within EHMC men to be disruptive and detrimental to some anabolic-androgenic testosterone-dependent physiological processes. Findings, while limited, suggest spermatogenesis problems may exist in some cases; thus, infertility risk in such men is a critical concern. Present evidence suggests the EHMC condition is limited to men who have been persistently involved in chronic endurance exercise training for an extended period of time, and thus is not a highly prevalent occurrence. Nevertheless, it is critical that endocrinologist and fertility clinicians become more aware of the existence of EHMC as a potential problem-diagnosis in their male patients who exercise.

Morphofunctional alterations of the nonpregnant murine uterus in response to intense and exhaustive exercise are not related to oxidative stress

Exercise is a common and noninvasive way to improve human health. In contrast, intense exercise causes damage in various tissues and is usually associated with metabolic changes in organs and tissues. Even though intense exercise is associated with dysfunctions in the female reproductive system, much less is known about the cellular mechanisms underlying its effects particularly on the nonpregnant uterus. We investigated whether the effects of an intense and exhaustive exercise (IEE) program on the isolated C57BL/6 uterine morphology and contractility might be related to increased levels of prooxidation markers. Female mice were submitted to 2 days of IEE. The daily exercise session consisted of a running session until exhaustion, with the treadmill speed set at 85% of each animal's maximum velocity. Training responses were evaluated through two parameters: time to exhaustion and maximum velocity. Absence of exercise-induced hypothalamic-pituitary-adrenal (HPA) axis activation was indirectly evaluated by maintenance of the adrenal gland weight. IEE reduced the thickness of the longitudinal muscular layer by 10%, impaired contractility in response to muscarinic stimulation (increased EC50 and decreased Emax), but showed a strong trend to decreasing the KCl-induced contraction; reduced lipid peroxidation; and did not alter the uterine protein oxidation of exercised animals compared with control. Altogether we provide evidence for the nonpregnant murine uterus being an important target to IEE, leading to morphofunctional alterations which could not be associated with tissue oxidative stress but might well be related with exercise-induced uterine dysfunctions.

Sex differences in the physiology of eating

Hypothalamic-pituitary-gonadal (HPG) axis function fundamentally affects the physiology of eating. We review sex differences in the physiological and pathophysiological controls of amounts eaten in rats, mice, monkeys, and humans. These controls result from interactions among genetic effects, organizational effects of reproductive hormones (i.e., permanent early developmental effects), and activational effects of these hormones (i.e., effects dependent on hormone levels). Male-female sex differences in the physiology of eating involve both organizational and activational effects of androgens and estrogens. An activational effect of estrogens decreases eating 1) during the periovulatory period of the ovarian cycle in rats, mice, monkeys, and women and 2) tonically between puberty and reproductive senescence or ovariectomy in rats and monkeys, sometimes in mice, and possibly in women. Estrogens acting on estrogen receptor-α (ERα) in the caudal medial nucleus of the solitary tract appear to mediate these effects in rats. Androgens, prolactin, and other reproductive hormones also affect eating in rats. Sex differences in eating are mediated by alterations in orosensory capacity and hedonics, gastric mechanoreception, ghrelin, CCK, glucagon-like peptide-1 (GLP-1), glucagon, insulin, amylin, apolipoprotein A-IV, fatty-acid oxidation, and leptin. The control of eating by central neurochemical signaling via serotonin, MSH, neuropeptide Y, Agouti-related peptide (AgRP), melanin-concentrating hormone, and dopamine is modulated by HPG function. Finally, sex differences in the physiology of eating may contribute to human obesity, anorexia nervosa, and binge eating. The variety and physiological importance of what has been learned so far warrant intensifying basic, translational, and clinical research on sex differences in eating.

Acute restraint stress increases intrahypothalamic oestradiol concentrations in conjunction with increased hypothalamic oestrogen receptor β and aromatase mRNA expression in female rats

Activation of the hypothalamic-pituitary-adrenal axis is considered to be one of the key physiological responses to stress and, interestingly, shows a marked sex difference. Oestradiol plays an important role in this sex difference. The present study investigated the systemic and intrahypothalamic oestradiol response to physical restraint stress in female rats. We used jugular catheterisation and intrahypothalamic microdialysis to simultaneously measure plasma oestradiol and local oestradiol concentrations in the paraventricular nucleus (PVN) of the hypothalamus. We also assessed corticotrophin-releasing hormone (CRH), aromatase, and oestrogen receptor (ER) α and β mRNA expression in the PVN by quantitative polymerase chain reaction immediately after the acute stress period. As expected, PVN CRH mRNA and plasma corticosterone were significantly increased after acute stress. Interestingly, the local oestradiol concentration in the PVN also increased during the 1-h stress period in pro-oestrus and in ovariectomised (OVX) animals. Aromatase mRNA expression in the PVN was increased markedly in pro-oestrus but only modestly in oestrus. PVN ERβ but not ERα mRNA expression was significantly elevated in pro-oestrous animals. In addition, plasma oestradiol levels increased 10 min after stress, both during pro-oestrus and oestrus but not in OVX animals. To conclude, we report an intra-hypothalamic oestradiol response to restraint stress. The rising hypothalamic oestradiol concentration together with increased ERβ gene expression indicates a positive feedback of hypothalamic oestradiol signalling during acute stress in rats.

Incidência da sindrome pré-menstrual na prática de esportes

Apesar do grande aumento do número de mulheres no esporte, é escassa a literatura sobre aspectos anatômicos, psicológicos e principalmente hormonais que afetam o desempenho das mulheres praticantes de exercício físico. Embora existam muitas pesquisas relatando como o exercício afeta a menstruação, são poucos os estudos de como o ciclo menstrual interfere no desempenho feminino. A maioria dos estudos cita a relação do desempenho e o ciclo menstrual, mas não leva em consideração as alterações do ciclo, as moléstias perimenstruais (MPM)(1). OBJETIVO: Observar a incidência e a frequência dos sintomas da síndrome pré-menstrual em atletas. CASUÍSTICA E MÉTODOS: Em 31 atletas de handebol em idade fértil foi aplicado um diário de sintomas pré-menstruais(2) por um período de três meses consecutivos. RESULTADOS: A prevalência de SPM em atletas foi de 71%, sendo o sintoma mais relatado o de irritabilidade, em 86,4% das atletas, seguidos de mudanças de humor (77,3%) e cólicas (72,7%); 59% das atletas indicaram algum outro sintoma no período pré-menstrual. CONCLUSÕES: Observou-se alta prevalência de SPM em atletas.

Mechanisms linking physical activity with cancer

About 25% of cancer cases globally are due to excess weight and a sedentary lifestyle. Physical activity may decrease risk for various cancers by several mechanisms, including decreasing sex hormones, metabolic hormones and inflammation, and improving immune function. The level of physical activity might also be associated with prognosis among individuals with cancer. Randomized clinical trials have shown that physical activity interventions can change biomarkers of cancer risk. Observational studies can also provide useful information on mechanisms that might link physical activity to cancer.

Predictors of late menarche and adult height in children with anorexia nervosa

OBJECTIVES

The onset of anorexia nervosa (AN) during childhood can affect the timing of puberty and adult height. The aim of the study was to evaluate the determinants of late menarche and adult height in children with AN.

PATIENTS AND METHODS

We carried out a retrospective, longitudinal, university hospital-based study. All prepubertal or early pubertal girls diagnosed with AN between 1998 and 2002 were selected for the study. Participants (n = 33) were studied at a median age of 21 (19.8-24.3) years. AN was diagnosed at 11.8 (10.7-12.3) years.

RESULTS

Patients with AN reached menarche at significantly greater ages than their mothers [15.4 (13.5-16.8) vs. 13.2 (12.0-14.5) years, P < 0.01]. Chronological age at onset of AN and lowest body mass index (BMI) were important independent predictive factors for delayed menarche (P < 0.01). Adult height was 165.0 (163.0-172.0) cm, 2.5 (-1.5 to 5.0) cm above target height. Twelve patients (36%) did not reach their target height and had a median height deficit of -3.9 cm with respect to their target height. The duration of hospitalization, a marker of disease severity and chronicity, was an independent predictor of the difference between adult height and target height for a given individual (beta coefficient = -0.07; P = 0.01). The other factors studied (i.e. age at onset of AN, pubertal stage at diagnosis of AN, lowest BMI reached, associated comorbidity if any, type of AN, age at menarche) had no significant effect on adult height.

CONCLUSION

The intensity of the disease affects the timing of menarche but not adult height in most patients. Hospitalization, despite often being an effective means of managing AN, does not reduce the impact of AN on growth.

Exercise and biomarkers for cancer prevention studies

The International Agency for Research on Cancer estimates that 25% of cancer cases worldwide are caused by overweight or obesity and a sedentary lifestyle. These lifestyle patterns may increase cancer risk by several mechanisms including increased estrogens and testosterone, hyperinsulinemia and insulin resistance, increased inflammation, and depressed immune function. Several randomized clinical trials have shown that physical activity and diet interventions can change biomarkers of cancer risk. In a controlled physical activity trial, we found decreases in serum estrogen, testosterone, and insulin in overweight, sedentary postmenopausal women with a 1-y exercise program consisting of moderate-intensity aerobic exercise, 45 min/d, 5 d/wk. In another controlled trial in middle-aged to older persons, we found that a 1-y exercise intervention of 60 min/d, 6 d/wk, reduced colon crypt cell proliferation in men who adhered closely to the program. Only 1 trial, the Women's Health Initiative Dietary Modification Trial, has published results of a dietary intervention on breast cancer incidence and reported a statistically nonsignificant 9% reduction in invasive breast cancer incidence in postmenopausal women following a low-fat dietary pattern for 8-12 y. Other trials under way are testing effects of weight loss, physical activity, and dietary patterns on other cancer biomarkers. The NCI-funded Transdisciplinary Research on Energetics and Cancer centers are exploring novel research into mechanisms linking energy balance with cancer risk and prevention. The worldwide trends toward increasing overweight and obesity and decreasing physical activity may lead to an increased incidence of several cancers unless other means of risk reduction counteract these effects. Thus, adoption of lifestyle changes by individuals and populations may have a large impact on the future incidence of cancer.

Metabolic and hormonal control of the desire for food and sex: implications for obesity and eating disorders

During evolution, the ability to overeat and store the extra energy as glycogen and lipids in specialized tissues must have conferred a reproductive advantage by releasing animals from the need to eat constantly, enabling them to engage in behaviors that improved reproductive success. Mechanisms that inhibited ingestive behavior might have been most adaptive when they caused individuals to stop foraging, hoarding and eating in order to find and court potential mates. Conversely, the ability to abstain from reproductive activities to engage in foraging and eating was probably critical for individual survival during severe energetic challenges because reproductive processes are energetically costly and can be delayed until the energetic conditions improve. The mechanisms that control ingestive behavior most likely evolved under conditions in which both food and mates were available, and thus, our understanding might be limited by our narrow focus on food intake in animals isolated from potential mates, and reproductive behaviors in the absence of food. Our understanding of obesity and eating disorders will be enriched by the study of the choice between ingestive and reproductive behaviors and by a renewed attention to "reproductive" hormones such as gonadal steroids and hypothalamic releasing hormones. Furthermore, leptin and reproductive hormones have both organizational and activational effects on the energy balancing system including those mechanisms that control appetite, body fat content and body fat distribution. Understanding these organizational and activational effects on body fat distribution might lead to a better understanding of sex differences in the propensity to develop obesity, type II diabetes and eating disorders.

Menstrual disorders in athletes

The various menstrual disorders in athletes may reflect different degrees of exposure to a disrupting factor or differences in the susceptibility of various women to disruption. The incidences of these disorders are not well documented, but they appear to be highest in aesthetic, endurance and weight-class sports, and at younger ages, higher training volumes and lower bodyweights. The morbid effects of these disorders include infertility, low bone mass, impaired endothelium-dependent vasodilation, and impaired skeletal muscle oxidative metabolism. The high incidences of menstrual disorders in athletes may derive in part from the self-selection of extraneously affected women into athletics, but many women acquire their menstrual disorders in athletics by failing to adequately increase dietary energy intake in compensation for exercise energy expenditure. Applied research is needed to develop effective dietary interventions that are acceptable to athletes.