Magnitude of daily energy deficit predicts frequency but not severity of menstrual disturbances associated with exercise and caloric restriction

Beyond Menstrual Dysfunction: Does Altered Endocrine Function Caused by Problematic Low Energy Availability Impair Health and Sports Performance in Female Athletes?

Low energy availability, particularly when problematic (i.e., prolonged and/or severe), has numerous negative consequences for health and sports performance as characterized in relative energy deficiency in sport. These consequences may be driven by disturbances in endocrine function, although scientific evidence clearly linking endocrine dysfunction to decreased sports performance and blunted or diminished training adaptations is limited. We describe how low energy availability-induced changes in sex hormones manifest as menstrual dysfunction and accompanying hormonal dysfunction in other endocrine axes that lead to adverse health outcomes, including negative bone health, impaired metabolic activity, undesired outcomes for body composition, altered immune response, problematic cardiovascular outcomes, iron deficiency, as well as impaired endurance performance and force production, all of which ultimately may influence athlete health and performance. Where identifiable menstrual dysfunction indicates hypothalamic-pituitary-ovarian axis dysfunction, concomitant disturbances in other hormonal axes and their impact on the athlete's health and sports performance must be recognized as well. Given that the margin between podium positions and "losing" in competitive sports can be very small, several important questions regarding low energy availability, endocrinology, and the mechanisms behind impaired training adaptations and sports performance have yet to be explored.

Determinants of menstrual dysfunction in the female athlete triad: A cross-sectional study in Italian athletes

BACKGROUND

In 1992 the American College of Sports Medicine first described the Female Athlete Triad. The Triad is a metabolic injury involving three distinct clinical traits: low energy availability, with possible eating disorder, low bone mineral density and menstrual dysfunction (MD). Although the estimated prevalence of the Triad is low (1.2 %), single factors are common in female athletes, at all competitive levels and ages. Even though the Triad was described over two decades ago, the interrelation of the three diagnostics components is still debated: additional evidence is required to improve the multidisciplinary treatment approach for this complex condition. MD is one of the first signs of energy impairment. The present study aims at investigating MD determinants and predictors in female athletes, to allow an early diagnosis of the Triad and to implement adequate preventive strategies.

MATERIALS AND METHODS

An original structured questionnaire was composed to detect the presence of MD risk factors. Included participants were active female athletes within reproductive age range (15-40 years old). Anthropometric parameters and training-related factors, possibly affecting the regularity of the menstrual cycle, were investigated.

RESULTS

Respondents were 288 female athletes. Among them, 73.3 % were under 25 years of age; 6.6 % resulted underweight; 30.6 % reported to follow a meal plan/diet and 13.9 % declared to be a smoker. Lean sports were practiced by 30.6 % of responders. Body-weight congruence was detected in in 79.9 % of participants, whereas overestimation of body image was found in 16.3 % of athletes. Irregular menstrual cycle, a possible MD predictor, was present in 33.0 % of athletes, with 41.1 % practicing some lean sport (p = 0.007). Also, overestimation of body image suggested an increased risk of menstrual irregularity (p = 0.001). BMI <18.5 or BMI >30 could also act as risk factor, although significance was not fully obtained (p = 0.053). Overall, practice of lean sports and overestimation of body image appeared good determinants of increased menstrual irregularity (AOR 2.02 and 3.83, respectively).

CONCLUSIONS

Menstrual irregularity in female athletes can be considered an early predictor of MD: risk is further increased in athletes of lean sports and reporting an overestimation of self-perceived body image. Screenings and awareness programs should specifically address female athletes, because of their vulnerable-group profile. In order to define a standardized at-risk profile for Triad onset and sequelae likelihood, evaluation of menstrual regularity should especially be considered, in conjunction with the assessment of other indicators of energy availability (e.g. TEE, lean and fat mass, BMC). Testing for sport-derived stress and disordered eating attitudes is also recommended. Preventive strategy should involve the proactive engagement of sport clubs and periodic competitive sport medical assessment.

Association between Physical Activity and Menstrual Cycle Disorders in Young Athletes

Our study aims to evaluate clinical predictors of menstrual cycle disorders in female athletes who compete in running disciplines. This is a prospective observational study. Women were recruited between January and May 2022. Fifty-three patients were enrolled and completed a questionnaire about menstrual cycle, physical activity, and food habit characteristics. Of the women in our population, 39.6% had menstrual irregularities and reported a significantly higher number of kilometers run per week (67 vs. 35, p:0.02). The number of kilometers run per week was associated with menstrual irregularities (for 10 km, OR 1.35; IC95% 1.05-1.73; p: 0.02) after adjusting for BMI, age, level of sport and caloric intake. The variable of "km run per week" appeared as a diagnostic indicator of irregular menstrual cycle with statistical significance (AUC ROC curve 0.71, IC95% 0.54-0.86, p-value=0.01) and the cut-off of 65 km run per week is a good indicator of the presence of irregular menstrual cycle (sensitivity (SE) and specificity (SP) of 55% and 81.48%). Menstrual cycle disorders are very frequent in female athletes, and the variable of km run per week may play a role in screening endurance athletes at high risk for these disorders.

Energy availability modulates regional blood flow via estrogen-independent pathways in regularly menstruating young women

PURPOSE

This study aimed to investigate the impact of short-term low energy availability (LEA) on vascular function in young, regularly menstruating women.

METHODS

Participants were 19 women, aged 22.9 ± 4.2 years, with body mass index 18-30 kg·m2. They were divided into two groups and completed two conditions in a crossover design: a 3-day control condition (CON) with an energy availability of 45 kcals·kgFFM-1·day-1 and a 3-day LEA condition of 15 kcals·kgFFM-1 day-1. Assessments were conducted during the early follicular phase of the menstrual cycle. Outcome measures included forearm blood flow (FBF), heart rate, blood pressure, arterial stiffness, resting energy expenditure (REE), metabolic blood markers and body composition.

RESULTS

Significant time-by-condition interactions were found for resting FBF (p = .004), REE (p = .042), triiodothyronine (p = .006), β-hydroxybutyrate (p = .002) and body mass (p < .001). Resting FBF was 1.43 ± 1.01 and 1.31 ± 0.61 (arbitrary units) at pre and post, respectively, in LEA and 1.52 ± 0.7 and 1.76 ± 0.57 at pre and post in CON. The LEA condition led to a decrease in triiodothyronine (pre: 1.54 ± 0.28, post: 1.29 ± 0.27 ng ml-1), REE (pre: 1588 ± 165, post: 1487 ± 160 kcals day-1) and body mass (pre: 61.4 ± 7.5, post: 59.6 ± 7.3 kg). Changes in resting FBF were significantly correlated with changes in REE in the LEA condition (r = 0.53; p = 0.02).

CONCLUSION

Short-term LEA modifies regional blood flow and this might contribute to the observed decreased in REE. Findings emphasize the need for careful management of energy availability in populations at risk of LEA.

Are menstrual disturbances associated with an energy availability threshold? A critical review of the evidence

Exercising women have a high prevalence of menstrual disturbances. In 2003, it was suggested that disruption in luteinizing hormone (LH) pulsatility occurs below a threshold of energy availability (EA) of 30 kcal/kg lean body mass (LBM)/day. This paper is a critical review of the evidence regarding the theory that disruptions to the reproductive axis and menstrual disturbances occur below the proposed threshold. Short-term laboratory studies demonstrated that 4-5 days of an EA below 30 kcal/kg LBM/day, induced with or without exercise, decreased serum triiodothyronine and LH pulse frequency, and increased LH pulse amplitude in sedentary, regularly menstruating women. Fewer studies have investigated downstream ovarian effects after long-term exposure to low EA. The Sargent Camp Study was the first randomized trial that induced luteal phase defects, delayed menses, and anovulation by causing weight loss (-4 ± 0.3 kg) with an abrupt increase in exercise volume for two menstrual cycles. The BioEnergetics Study was a randomized controlled trial that induced varying levels of energy deficits by manipulating energy intake and expenditure for three menstrual cycles. LH pulse frequency and triiodothyronine decreased, and 57% of women developed luteal phase defects, anovulation, and/or oligomenorrhea. An EA below 30 kcal/kg fat free mass/day increased the chance of experiencing a menstrual disturbance by 50%. However, menstrual disturbances were observed above and below that EA threshold, and changes in LH pulse frequency predicted only luteal phase defects, not oligomenorrhea or anovulation. The proposed EA threshold is not a cut-off below which menstrual disturbances occur, but represents an increased risk of experiencing menstrual disturbances.

Menstrual cycles and the impact upon performance in elite British track and field athletes: a longitudinal study

Objective

To assess the prevalence of menstrual disorders and the perceived effect of menstrual cycles upon performance in elite athletes.

Methodology

A longitudinal survey in the form of a questionnaire was sent to female track and field athletes at British Athletics every 6 months, over a five-year period between 1st October 2014 and 1st October 2019 in the United Kingdom (UK).

Results

128 athletes completed an average of 4.2 ± 2.9 questionnaires across the study period. The mean age of menarche was 14.2 ± 1.4 years, 13.4 ± 1.3 years and 12.8 ± 1.4 years in endurance, power, and thrower athletes respectively (p < 0.05). Two-thirds (66%; n = 82) reported consistently regular cycles, 30% (n = 37) irregular at some point during the period of observation and 4% (n = 5) were amenorrhoeic. 87 athletes (68%) reported dysmenorrhoea and 40 (31%) menorrhagia. More than three quarters (76.8%; n = 96) described their cycle negatively affected performance. Amongst those who reported when the negative impact occurred (n = 91), 40% (n = 36) reported this in the late luteal phase and 35% (n = 32) during the early follicular phase. 79% (n = 100) of athletes reported at least one cyclical symptom, of which bloating, lower back and pelvic pain were most frequently experienced.

Conclusion

This data highlights the complex interrelationship between women's health and elite athletic performance. Athletes perceive a negative impact from their menstrual cycles upon performance with a desire to manage these more effectively, particularly during competition. Female reproductive health expertise in the multi-disciplinary management of elite athletes is required.

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.

Adolescence is characterized by more sedentary behaviour and less physical activity even among highly active forager-farmers

Over 80% of adolescents worldwide are insufficiently active, posing massive public health and economic challenges. Declining physical activity (PA) and sex differences in PA consistently accompany transitions from childhood to adulthood in post-industrialized populations and are attributed to psychosocial and environmental factors. An overarching evolutionary theoretical framework and data from pre-industrialized populations are lacking. This cross-sectional study tests hypotheses from life history theory, that adolescent PA is inversely related to age, but this association is mediated by Tanner stage, reflecting higher and sex-specific energetic demands for growth and reproductive maturation. Detailed measures of PA and pubertal maturation are assessed among Tsimane forager-farmers (age: 7-22 years; 50% female, n = 110). Most Tsimane sampled (71%) meet World Health Organization PA guidelines (greater than or equal to 60 min/day of moderate-to-vigorous PA). Like post-industrialized populations, sex differences and inverse age-activity associations were observed. Tanner stage significantly mediated age-activity associations. Adolescence presents difficulties to PA engagement that warrant further consideration in PA intervention approaches to improve public health.

2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs)

Relative Energy Deficiency in Sport (REDs) was first introduced in 2014 by the International Olympic Committee's expert writing panel, identifying a syndrome of deleterious health and performance outcomes experienced by female and male athletes exposed to low energy availability (LEA; inadequate energy intake in relation to exercise energy expenditure). Since the 2018 REDs consensus, there have been >170 original research publications advancing the field of REDs science, including emerging data demonstrating the growing role of low carbohydrate availability, further evidence of the interplay between mental health and REDs and more data elucidating the impact of LEA in males. Our knowledge of REDs signs and symptoms has resulted in updated Health and Performance Conceptual Models and the development of a novel Physiological Model. This Physiological Model is designed to demonstrate the complexity of either problematic or adaptable LEA exposure, coupled with individual moderating factors, leading to changes in health and performance outcomes. Guidelines for safe and effective body composition assessment to help prevent REDs are also outlined. A new REDs Clinical Assessment Tool-Version 2 is introduced to facilitate the detection and clinical diagnosis of REDs based on accumulated severity and risk stratification, with associated training and competition recommendations. Prevention and treatment principles of REDs are presented to encourage best practices for sports organisations and clinicians. Finally, methodological best practices for REDs research are outlined to stimulate future high-quality research to address important knowledge gaps.

Mapping the complexities of Relative Energy Deficiency in Sport (REDs): development of a physiological model by a subgroup of the International Olympic Committee (IOC) Consensus on REDs

The 2023 International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs) notes that exposure to low energy availability (LEA) exists on a continuum between adaptable and problematic LEA, with a range of potential effects on both health and performance. However, there is variability in the outcomes of LEA exposure between and among individuals as well as the specific manifestations of REDs. We outline a framework for a 'systems biology' examination of the effect of LEA on individual body systems, with the eventual goal of creating an integrated map of body system interactions. We provide a template that systematically identifies characteristics of LEA exposure (eg, magnitude, duration, origin) and a variety of moderating factors (eg, medical history, diet and training characteristics) that could exacerbate or attenuate the type and severity of impairments to health and performance faced by an individual athlete. The REDs Physiological Model may assist the diagnosis of underlying causes of problems associated with LEA, with a personalised and nuanced treatment plan promoting compliance and treatment efficacy. It could also be used in the strategic prevention of REDs by drawing attention to scenarios of LEA in which impairments of health and performance are most likely, based on knowledge of the characteristics of the LEA exposure or moderating factors that may increase the risk of harmful outcomes. We challenge researchers and practitioners to create a unifying and dynamic physiological model for each body system that can be continuously updated and mapped as knowledge is gained.

High-impact jumping mitigates the short-term effects of low energy availability on bone resorption but not formation in regularly menstruating females: A randomized control trial

Low energy availability (LEA) is prevalent in active individuals and negatively impacts bone turnover in young females. High-impact exercise can promote bone health in an energy efficient manner and may benefit bone during periods of LEA. Nineteen regularly menstruating females (aged 18-31 years) participated in two three-day conditions providing 15 (LEA) and 45 kcals kg fat-free mass-1  day-1 (BAL) of energy availability, each beginning 3 ± 1 days following the self-reported onset of menses. Participants either did (LEA+J, n = 10) or did not (LEA, n = 9) perform 20 high-impact jumps twice per day during LEA, with P1NP, β-CTx (circulating biomarkers of bone formation and resorption, respectively) and other markers of LEA measured pre and post in a resting and fasted state. Data are presented as estimated marginal mean ± 95% CI. P1NP was significantly reduced in LEA (71.8 ± 6.1-60.4 ± 6.2 ng mL-1 , p < 0.001, d = 2.36) and LEA+J (93.9 ± 13.4-85.2 ± 12.3 ng mL-1 , p < 0.001, d = 1.66), and these effects were not significantly different (time by condition interaction: p = 0.269). β-CTx was significantly increased in LEA (0.39 ± 0.09-0.46 ± 0.10 ng mL-1 , p = 0.002, d = 1.11) but not in LEA+J (0.65 ± 0.08-0.65 ± 0.08 ng mL-1 , p > 0.999, d = 0.19), and these effects were significantly different (time by condition interaction: p = 0.007). Morning basal bone formation rate is reduced following 3 days LEA, induced via dietary restriction, with or without high-impact jumping in regularly menstruating young females. However, high-impact jumping can prevent an increase in morning basal bone resorption rate and may benefit long-term bone health in individuals repeatedly exposed to such bouts.

Amenorrhea and oligomenorrhea risk related to exercise training volume and intensity: Findings from 3705 participants recruited via the STRAVA™ exercise application

OBJECTIVES

To investigate associations between self-reported exercise training habits and amenorrhea/oligomenorrhea among physically active women.

DESIGN

A cross-sectional survey was completed by 3705 women (median age = 40 years [quartile 1, quartile 3: 30, 45], body mass index = 22.1 kg/m2 [20.5, 24.2]) representing multiple nationalities and sports via the STRAVA™ exercise application. Respondents selected the amount of time they participated in low intensity, moderate intensity, and high intensity exercise training per week. Amenorrhea/oligomenorrhea was defined as self-reporting ≤10 menses in the last year.

METHODS

Associations between weekly exercise volume for low intensity training, moderate intensity training, and high intensity training and amenorrhea/oligomenorrhea were modeled with univariate logistic regression models, followed by adjustment for age and body mass index.

RESULTS

Amenorrhea/oligomenorrhea prevalence was 16 % (n = 576/3705), with no difference by country of origin or most sport modes. In adjusted models, participating in low intensity training ≥7 h/week or moderate intensity training ≥6 h/week was associated with 1.43 (95 % confidence interval: 1.04-1.96) and 1.46 (1.10-1.95) greater odds of amenorrhea/oligomenorrhea compared to 2 to 3 h/week, respectively. Similarly, high intensity training ≥5 h/week was associated with 1.41 (1.03-1.92) greater odds of amenorrhea/oligomenorrhea compared to 1 to 2 h/week. Participating in low intensity training for ≤30 min/week compared to 2 to 3 h/week was associated with reduced amenorrhea/oligomenorrhea odds (0.65 [0.44-0.94]).

CONCLUSIONS

Taken together, these associations suggest greater weekly exercise volume, irrespective of intensity, may increase amenorrhea/oligomenorrhea risk among physically active women.

The Influence of Energy Balance and Availability on Resting Metabolic Rate: Implications for Assessment and Future Research Directions

Resting metabolic rate (RMR) is a significant contributor to an individual's total energy expenditure. As such, RMR plays an important role in body weight regulation across populations ranging from inactive individuals to athletes. In addition, RMR may also be used to screen for low energy availability and energy deficiency in athletes, and thus may be useful in identifying individuals at risk for the deleterious consequences of chronic energy deficiency. Given its importance in both clinical and research settings within the fields of exercise physiology, dietetics, and sports medicine, the valid assessment of RMR is critical. However, factors including varying states of energy balance (both short- and long-term energy deficit or surplus), energy availability, and prior food intake or exercise may influence resulting RMR measures, potentially introducing error into observed values. The purpose of this review is to summarize the relationships between short- and long-term changes in energetic status and resulting RMR measures, consider these findings in the context of relevant recommendations for RMR assessment, and provide suggestions for future research.

The effect of physical activity on fertility: a mini-review

Although lifestyle factors such as diet, cigarette smoking, and alcohol consumption are increasingly recognized as important contributors to the risk of subfertility, the role of exercise in fertility remains less clear. As such, it is challenging for healthcare providers to deliver clear, evidence-based recommendations to patients regarding the optimal frequency and intensity with which they should exercise to maximize their chances of conception. Therefore, this review provides a critical overview of the available research for various patient populations.

Adolescence is characterized by more sedentary behavior and less physical activity even among highly active forager-farmers

Over 80% of adolescents worldwide are insufficiently active, posing massive public health and economic challenges. Declining physical activity (PA) and sex differences in PA consistently accompany transitions from childhood to adulthood in post-industrialized populations and are attributed to psychosocial and environmental factors. An overarching evolutionary theoretical framework and data from pre-industrialized populations are lacking. In this cross-sectional study we test a hypothesis from life history theory, that adolescent PA reductions reflect an evolved strategy to conserve energy, given the increasing sex-specific energetic demands for growth and reproductive maturation. Detailed measures of PA and pubertal maturation are assessed among Tsimane forager-farmers (age: 7-22 yrs.; 50% female, n=110). We find that 71% of Tsimane sampled meet World Health Organization PA guidelines (≥60 minutes/day of moderate-to-vigorous PA). Consistent with post-industrialized populations, we observe sex differences and inverse age-activity associations mediated by Tanner stage. Physical inactivity in adolescence is distinct from other health risk behaviors and also not merely resulting from obesogenic environments.

The role of exercise in obesity-related cancers: Current evidence and biological mechanisms

Cancer ranks among the five leading causes of death in almost all countries and has important repercussions for individual and public health, the healthcare system, and society in general. Obesity increases the incidence of many types of cancer, but growing evidence suggests that physical activity may decrease risk for developing a variety of obesity-related cancer types, and, in some cases, may improve cancer prognosis and mortality rates. This review summarizes recent evidence on the effect of physical activity on obesity-related cancer prevention and survival. For some cancers, including breast, colorectal, and endometrial cancer, there is strong evidence for a preventative effect of exercise, but for many others, including gallbladder and kidney cancer, and multiple myeloma, evidence is inconsistent or largely lacking. Though many potential mechanisms have been proposed to explain the onco-protective effect of exercise, including improved insulin sensitivity, alterations in sex hormone availability, improved immune function and inflammation, myokine secretion, and modulation of intracellular signaling at the level of AMP kinase, the exact mechanism(s) of action within each cancer subtype remains poorly defined. Overall, a deeper understanding of how exercise can help against cancer and of the exercise parameters that can be altered to optimize exercise prescription is necessary and should be the subject of future investigation.

The effects of weight loss-related amenorrhea on women's health and the therapeutic approaches: a narrative review

Background and Objective

Weight loss-related amenorrhea is defined as the reversible functional inhibition of the hypothalamic-pituitary-ovarian (HPO) axis associated with weight loss or low body weight, which occurs mostly in adolescents and women of reproductive age. The specific pathological mechanisms of this disease have not yet been elucidated, and the optimal evidence-based guidelines for its clinical assessment and management are limited. This review summarizes its adverse effects on female health, and the individualized, emerging, and multidisciplinary therapeutic approaches used to treat it.

Methods

We searched the PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI) databases for Chinese and English literature on functional hypothalamic amenorrhea (FHA), and retrieved original articles (on basic and clinical research) and reviews published up to December 2022.

Key Content and Findings

We reviewed the findings on the unfavorable effects of weight loss-related amenorrhea with a focus on reproduction, the skeletal and cardiovascular system, other endocrine effects, and mental health. Lifestyle changes and hormonal replacement have been shown to alleviate the underlying causes and lead to the recovery of menstruation. However, the efficacy of treatments is affected by many factors, such as psychological stress and heterogeneity.

Conclusions

Weight loss-related amenorrhea, which is an important type of FHA, is manifested by anovulation and hypoestrogenism, and has both short- and long-term adverse effects on women's overall health. It is difficult to alleviate its underlying causes. Individualized treatments need to be optimized and emerging or multidisciplinary therapeutic approaches need to be explored that aim to recover normal menstruation and ovulation, eliminate the undesirable effects of prolonged hypoestrogenism and alleviate psychological disorders.

Physical and Physiological Characterization of Female Elite Warfighters

INTRODUCTION

This study characterized a sample of the first women to complete elite United States (US) military training.

METHODS

Twelve female graduates of the US Army Ranger Course and one of the first Marine Corps Infantry Officers Course graduates participated in 3 d of laboratory testing including serum endocrine profiles, aerobic capacity, standing broad jump, common soldiering tasks, Army Combat Fitness Test, and body composition (dual-energy x-ray absorptiometry, three-dimensional body surface scans, and anthropometry).

RESULTS

The women were 6 months to 4 yr postcourse graduation, 30 ± 6 yr (mean ± SD); height, 1.67 ± 0.07 m; body mass, 69.4 ± 8.2 kg; body mass index, 25.0 ± 2.3 kg·m -2 . Dual-energy x-ray absorptiometry relative fat was 20.0% ± 2.0%; fat-free mass, 53.0 ± 5.9 kg; fat-free mass index, 20.0 ± 1.7 kg·m -2 ; bone mineral content, 2.75 ± 0.28 kg; bone mineral density, 1.24 ± 0.07 g·cm -2 ; aerobic capacity, 48.2 ± 4.8 mL·kg -1 ·min -1 ; total Army Combat Fitness Test score 505 ± 27; standing broad jump 2.0 ± 0.2 m; 123 kg casualty drag 0.70 ± 0.20 m·s -1 , and 4 mile 47 kg ruck march 64 ± 6 min. All women were within normal healthy female range for circulating androgens. Physique from three-dimensional scan demonstrated greater circumferences at eight of the 11 sites compared with the standard military female.

CONCLUSIONS

These pioneering women possessed high strength and aerobic capacity, low %BF; high fat-free mass, fat-free mass index, and bone mass and density; and they were not virilized based on endocrine measures as compared with other reference groups. This group is larger in body size and leaner than the average Army woman. These elite physical performers seem most comparable to female competitive strength athletes.

Female Athlete Triad and Male Athlete Triad Syndrome Induced by Low Energy Availability: An Animal Model

Energy availability (EA) is defined the difference in energy intake and exercise energy expenditure. Reduction of EA (i.e. Low energy availability, LEA) often causes abnormalities of reproduction system and drastic bone loss in some female athletes, the phenomenon is called as female athlete triad. More than ever before, it is considered a serious problem, the reason of these are (1) the syndrome occurred in female athletes but also male athletes, (2) LEA is leads to dysfunction of various organs other than reproductive system (Relative energy deficiency in sport, RED-S). On the other hand, we have focused on this syndrome and have proposed novel insights into the physiological effects of LEA on bone and solutions through nutritional treatment by recreating it in animal models. In this review, we will summarize the epidemiological and physiological perspectives of these diseases from historical background to recent findings, and introduce the usefulness of using animal models to explore mechanisms and treatments.

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.

Dietary Iron and the Elite Dancer

Dancers are an athlete population at high risk of developing iron deficiency (ID). The aesthetic nature of the discipline means dancers potentially utilise dietary restriction to meet physique goals. In combination with high training demands, this means dancers are susceptible to problems related to low energy availability (LEA), which impacts nutrient intake. In the presence of LEA, ID is common because of a reduced mineral content within the low energy diet. Left untreated, ID becomes an issue that results in fatigue, reduced aerobic work capacity, and ultimately, iron deficient anaemia (IDA). Such progression can be detrimental to a dancer’s capacity given the physically demanding nature of training, rehearsal, and performances. Previous literature has focused on the manifestation and treatment of ID primarily in the context of endurance athletes; however, a dance-specific context addressing the interplay between dance training and performance, LEA and ID is essential for practitioners working in this space. By consolidating findings from identified studies of dancers and other relevant athlete groups, this review explores causal factors of ID and potential treatment strategies for dancers to optimise absorption from an oral iron supplementation regime to adequately support health and performance.

Impact of Low Energy Availability on Skeletal Health in Physically Active Adults

For decades researchers reported that pre-menopausal women who engage in extensive endurance exercise and have menstrual dysfunction can develop low bone mineral density (BMD) or osteoporosis. More recently, low energy availability has been recognized as the initiating factor for low BMD in these women. Furthermore, the relationship between low energy availability and poor skeletal health is not exclusive to women engaging in endurance exercise. Rather, both males and females commonly experience endocrine dysfunction resulting from low energy availability and high exercise levels that degrades skeletal health. Consequences to skeletal health can range from short-term changes in bone metabolism and increased risk of bone stress injuries to long-term consequences of low BMD, such as osteoporosis and related fragility fractures. The degree to which low energy availability degrades skeletal health may be dependent on the length and extent of the energy deficit. However, the complex relationships between under-fueling, short- and long-term skeletal consequences and the factors that mediate these relationships are not well described. In this review, we discuss the consequences of low energy availability on sex hormones and skeletal health in two highly-active populations-athletes and military trainees-and provide a summary of existing knowledge gaps for future study.

Nutrition and Physical Activity During British Army Officer Cadet Training: Part 1-Energy Balance and Energy Availability

Military training is characterized by high daily energy expenditures which are difficult to match with energy intake, potentially resulting in negative energy balance (EB) and low energy availability (EA). The aim of this study was to quantify EB and EA during British Army Officer Cadet training. Thirteen (seven women) Officer Cadets (mean ± SD: age 24 ± 3 years) volunteered to participate. EB and EA were estimated from energy intake (weighing of food and food diaries) and energy expenditure (doubly labeled water) measured in three periods of training: 9 days on-camp (CAMP), a 5-day field exercise (FEX), and a 9-day mixture of both CAMP and field-based training (MIX). Variables were compared by condition and gender with a repeated-measures analysis of variance. Negative EB was greatest during FEX (-2,197 ± 455 kcal/day) compared with CAMP (-692 ± 506 kcal/day; p < .001) and MIX (-1,280 ± 309 kcal/day; p < .001). EA was greatest in CAMP (23 ± 10 kcal·kg free-fat mass [FFM]-1·day-1) compared with FEX (1 ± 16 kcal·kg FFM-1·day-1; p = .002) and MIX (10 ± 7 kcal·kg FFM-1·day-1; p = .003), with no apparent difference between FEX and MIX (p = .071). Irrespective of condition, there were no apparent differences between gender in EB (p = .375) or EA (p = .385). These data can be used to inform evidenced-based strategies to manage EA and EB during military training, and enhance the health and performance of military personnel.

Does exercise affect bone mineral density and content when added to a calorie-restricted diet? A systematic review and meta-analysis of controlled clinical trials

The effects of exercise in conjunction with weight-loss diets on bone health are mixed. Our objective was to systematically review and meta-analyze controlled clinical trials in adults investigating the addition of exercise to a weight-loss diet compared with a calorie-matched weight-loss diet without exercise on bone measures. Online databases including PubMed/MEDLINE, EMBASE, ISI (Web of Science), Scopus, and Google Scholar were searched up to April 2021 with no restriction. A random effects model was used to calculate the overall estimates. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Fourteen eligible controlled clinical trials were included in the systematic review. The meta-analysis revealed that, compared to weight-loss diets alone, the addition of exercise did not improve total body bone mineral density (BMD) [weighted mean difference (WMD) = 0.002 g/cm², P = 0.62, n = 8], lumbar BMD (WMD = 0.007 g/cm², P = 0.44, n = 9), total hip BMD (WMD = 0.015 g/cm², P = 0.14, n = 4) and total bone mineral content (BMC) (WMD =  - 11.97 g, P = 0.29, n = 7). Subgroup analysis revealed that resistance exercise in conjunction with hypocaloric diets positively affects total BMD compared to an energy restrictive diet alone (WMD = 0.01 g/cm², P = 0.003, n = 3). Overall, it appears that only resistance exercise beneficially affects total BMD during a calorie-restricted diet in adults. Further well-controlled and long-term clinical trials are still needed to confirm these results. PROSPERO registration number: CRD42020173434.

The female athlete triad: review of current literature

PURPOSE OF REVIEW

Adolescence and young adulthood are a critical period in the life of women for optimizing long-term bone health. Young athletes lead a demanding lifestyle with increased dietary requirements to meet the robust demands of energy expenditure to maintain a state of energy balance. During a time of fast paced changes and unpredictable societal demands on young athletes, it is important to review the severe consequences of energy deficiency and options for adequate management.

RECENT FINDINGS

This review focuses on hormonal adaptations that occur in energy deficient female athletes that lead to menstrual irregularities and impaired bone health, increasing the risk for stress and other fractures. We also describe management strategies to mitigate the consequences of limited energy availability on bone and other outcomes.

SUMMARY

These strategies should help guide the management of young female athletes to prevent irreversible changes to their bone health. Identifying current knowledge should help increase awareness among medical providers, which can then be communicated to the sports community, parents, and athletes.

The female athlete triad

The female athlete triad represents the 3 interrelated components: of energy availability (EA), menstrual function and bone health. Each component exists on a spectrum ranging from optimal health to dysfunction. Screening for the triad during the annual wellness exam, the preparticipation physical evaluation (PPE) or when the athlete presents with any single component can help identify athletes at risk. A multidisciplinary team is helpful in managing the treatment of the Triad which relies on improving EA. Screening, early recognition and aggressive treatment is important, especially in adolescent athletes to optimize bone health.

The Path Towards Progress: A Critical Review to Advance the Science of the Female and Male Athlete Triad and Relative Energy Deficiency in Sport

Energy status plays a key role in the health of athletes and exercising individuals. Energy deficiency/low energy availability (EA), referring to a state in which insufficient energy intake and/or excessive exercise energy expenditure has resulted in compensatory metabolic adaptations to conserve fuel, can affect numerous physiological systems in women and men. The Female Athlete Triad, Male Athlete Triad, and Relative Energy Deficiency in Sport (RED-S) models conceptualize the effects of energy deficiency in athletes, and each model has strengths and limitations. For instance, the Female Athlete Triad model depicts relationships between low EA, reproductive, and bone health, underpinning decades of experimental evidence, but may be perceived as limited in scope, while the more recent RED-S model proposes a wider range of potential health effects of low EA, though many model components require more robust scientific justification. This critical review summarizes current evidence regarding the effects of energy deficiency on athlete health by addressing the quality of the underlying science, the strengths and limitations of each model, and highlighting areas where future research is needed to advance the field. With the health and wellness of athletes and exercising individuals as the overarching priority, we conclude with specific steps that will help focus future research on the Female and Male Athlete Triad and RED-S, and encourage all researchers, clinicians, and practitioners to collaborate to support the common goal of promoting the highest quality science and evidence-based medicine in pursuit of the advancement of athletes' health, well-being, and performance.

Relationship between weight management and menstrual status in female athletes: a cross-sectional survey

The aim of this study was to investigate the effects of weight management on menstrual status in female athletes. A total of 225 collegiate athletes and 27 para-athletes who belonged to teams affiliated with the Japanese Paralympic Committee were included in this cross-sectional survey. A self-reported questionnaire (containing information on the demographic characteristics, medical history, lifestyle habits, weight management, menstruation status, physical symptoms related to menstrual cycle, and the influence of physical symptoms experienced during the luteal phase of menstruation during training or competition.) was used to assess the results. In the collegiate athletes, the rate of regular menstrual cycle was significantly lower in those with weight loss than in those without (56.7% vs. 75.0%, P < .05). Furthermore, stress fractures were found significantly more often in those with weight loss than those without (36.1% vs. 20.3%, P < .05). In the para-athletes, 46.2% of experience in weight loss had irregular menstruations (P < .01), and all of them had physical symptoms that negatively affected their training or competition (P < .05). To prevent menstrual dysfunction related to energy deficiency in female athletes with weight management, menstrual status must be considered.

Has Menstruation Disappeared? Functional Hypothalamic Amenorrhea-What Is This Story about?

Functional hypothalamic amenorrhea (FHA) is a very common condition affecting women of procreative age. There are many reasons for this disorder, including a low availability of energy in the diet, low micro- and macronutrient intake, overly intensive physical activity, disturbed regeneration processes, sleep disorders, stress, and psychological disorders. The main determinant is long-term stress and an inability to handle the effects of that stress. FHA is a very complex disorder and often goes undiagnosed. Moreover, therapeutic interventions do not address all the causes of the disorder, which could have implications for women’s health. As shown by scientific reports, this condition can be reversed by modifying its causes. This review of the literature aims to update the current knowledge of functional hypothalamic amenorrhea and underscores the complexity of the disorder, with particular emphasis on the nutritional aspects and potential interventions for restoring balance.

Randomised controlled trial of the effects of increased energy intake on menstrual recovery in exercising women with menstrual disturbances: the 'REFUEL' study

STUDY QUESTION

Does increased daily energy intake lead to menstrual recovery in exercising women with oligomenorrhoea (Oligo) or amenorrhoea (Amen)?

SUMMARY ANSWER

A modest increase in daily energy intake (330 ± 65 kcal/day; 18 ± 4%) is sufficient to induce menstrual recovery in exercising women with Oligo/Amen.

WHAT IS KNOWN ALREADY

Optimal energy availability is critical for normal reproductive function, but the magnitude of increased energy intake necessary for menstrual recovery in exercising women, along with the associated metabolic changes, is not known.

STUDY DESIGN, SIZE, DURATION

The REFUEL study (trial # NCT00392873) is the first randomised controlled trial to assess the effectiveness of 12 months of increased energy intake on menstrual function in 76 exercising women with menstrual disturbances. Participants were randomised (block method) to increase energy intake 20-40% above baseline energy needs (Oligo/Amen + Cal, n = 40) or maintain energy intake (Oligo/Amen Control, n = 36). The study was performed from 2006 to 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were Amen and Oligo exercising women (age = 21.0 ± 0.3 years, BMI = 20.8 ± 0.2 kg/m2, body fat = 24.7 ± 0.6%) recruited from two universities. Detailed assessment of menstrual function was performed using logs and measures of daily urinary ovarian steroids. Body composition and metabolic outcomes were assessed every 3 months.

MAIN RESULTS AND THE ROLE OF CHANCE

Using an intent-to-treat analysis, the Oligo/Amen + Cal group was more likely to experience menses during the intervention than the Oligo/Amen Control group (P = 0.002; hazard ratio [CI] = 1.91 [1.27, 2.89]). In the intent-to-treat analysis, the Oligo/Amen + Cal group demonstrated a greater increase in energy intake, body weight, percent body fat and total triiodothyronine (TT3) compared to the Oligo/Amen Control group (P < 0.05). In a subgroup analysis where n = 22 participants were excluded (ambiguous baseline menstrual cycle, insufficient time in intervention for menstrual recovery classification), 64% of the Oligo/Amen + Cal group exhibited improved menstrual function compared with 19% in the Oligo/Amen Control group (χ2, P = 0.001).

LIMITATIONS, REASONS FOR CAUTION

While we had a greater than expected dropout rate for the 12-month intervention, it was comparable to other shorter interventions of 3-6 months in duration. Menstrual recovery defined herein does not account for quality of recovery.

WIDER IMPLICATIONS OF THE FINDINGS

Expanding upon findings in shorter, non-randomised studies, a modest increase in daily energy intake (330 ± 65 kcal/day; 18 ± 4%) is sufficient to induce menstrual recovery in exercising women with Oligo/Amen. Improved metabolism, as demonstrated by a modest increase in body weight (4.9%), percent body fat (13%) and TT3 (16%), was associated with menstrual recovery.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the U.S. Department of Defense: U.S. Army Medical Research and Material Command (Grant PR054531). Additional research assistance provided by the Penn State Clinical Research Center was supported by the National Center for Advancing Translation Sciences, National Institutes of Health, through Grant UL1 TR002014. M.P.O. was supported in part by the Loretta Anne Rogers Chair in Eating Disorders at University of Toronto and University Health Network. All authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

NCT00392873.

TRIAL REGISTRATION DATE

October 2006.

DATE OF FIRST PATIENT’S ENROLMENT

September 2006.

The development and initial validation of the Health and Reproductive Survey (HeRS)

Background:

Due to the diversity in profiles associated with the female reproductive cycle and their potential physiological and psychological effects, monitoring the reproductive status of exercising females is important from a practical and research perspective. Moreover, as physical activity can influence menstrual function, the effects of physical activity energy expenditure on reproductive function should also be considered.

Aim:

The aim of this study was to develop and establish initial face and content validity of the Health and Reproductive Survey (HeRS) for physically active females, which is a retrospective assessment of menstrual function from menarche (first menstruation) to menopause (cessation of menstruation).

Methods:

Face validity was evaluated qualitatively, and the initial content validity was established through a principal component analysis. The face validity process was completed by 26 females aged 19–67 years and the content validity was established through a survey sent to a convenience sample of 392 females, of which 230 females (57.9% and aged 18–49 years) completed the survey.

Results:

The revisions made following the face validation improved the understanding, flow, and coherence of the survey. The principal component analysis indicated that, at a minimum, the survey measures these constructs: menstrual cessation and associated moderators, athletic participation and performance levels (as associated with menstruation change and the menstrual cycle), age and menstrual cessation, hormonal contraception (“birth control”), and menarche and associated moderators.

Conclusion:

The Health and Reproductive Survey (HeRS) is a partially validated tool that can be used by researchers to characterize the menstrual status of physically active females relative to their physical activity status.

Reproductive and metabolic adaptation to multistressor training in women

Hypothalamic-pituitary-gonadal (HPG) axis suppression in exercising women can be caused by low energy availability (EA), but the impact of a real-world, multistressor training environment on reproductive and metabolic function is unknown. This study aimed to characterize reproductive and metabolic adaptation in women undertaking basic military training. A prospective cohort study in women undertaking 11-month initial military training (n = 47) was carried out. Dynamic low-dose 1-h gonadotrophin-releasing hormone (GnRH) tests were completed after 0 and 7 mo of training. Urine progesterone was sampled weekly throughout. Body composition (dual X-ray absorptiometry), fasting insulin resistance (homeostatic modeling assessment 2, HOMA2), leptin, sex steroids, anti-Müllerian hormone (AMH), and inhibin B were measured after 0, 7, and 11 mo with an additional assessment of body composition at 3 mo. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) responses were suppressed after 7 mo (both P < 0.001). Among noncontraceptive users (n = 20), 65% had regular (23-35 days) cycles preenrollment, falling to 24% by 7 mo of training. Of women in whom urine progesterone was measured (n = 24), 87% of cycles showed no evidence of ovulation. There was little change in AMH, LH, and estradiol, although inhibin B and FSH increased (P < 0.05). Fat mass fluctuated during training but at month 11 was unchanged from baseline. Fat-free mass did not change. Visceral adiposity, HOMA2, and leptin increased (all P < 0.001). HPG axis suppression with anovulation occurred in response to training without evidence of low EA. Increased insulin resistance may have contributed to the observed pituitary and ovarian dysfunction. Our findings are likely to represent an adaptive response of reproductive function to the multistressor nature of military training.NEW & NOTEWORTHY We characterized reproductive endocrine adaptation to prolonged arduous multistressor training in women. We identified marked suppression of hypothalamic-pituitary-gonadal (HPG) axis function during training but found no evidence of low energy availability despite high energy requirements. Our findings suggest a complex interplay of psychological and environmental stressors with suppression of the HPG axis via activation of the hypothalamic-pituitary adrenal (HPA) axis. The neuroendocrine impact of nonexercise stressors on the HPG axis during arduous training should be considered.

The Male Athlete Triad-A Consensus Statement From the Female and Male Athlete Triad Coalition Part 1: Definition and Scientific Basis

ABSTRACT

The Male Athlete Triad is a syndrome of 3 interrelated conditions most common in adolescent and young adult male endurance and weight-class athletes and includes the clinically relevant outcomes of (1) energy deficiency/low energy availability (EA) with or without disordered eating/eating disorders, (2) functional hypothalamic hypogonadism, and (3) osteoporosis or low bone mineral density with or without bone stress injury (BSI). The causal role of low EA in the modulation of reproductive function and skeletal health in the male athlete reinforces the notion that skeletal health and reproductive outcomes are the primary clinical concerns. At present, the specific intermediate subclinical outcomes are less clearly defined in male athletes than those in female athletes and are represented as subtle alterations in the hypothalamic-pituitary-gonadal axis and increased risk for BSI. The degree of energy deficiency/low EA associated with such alterations remains unclear. However, available data suggest a more severe energy deficiency/low EA state is needed to affect reproductive and skeletal health in the Male Athlete Triad than in the Female Athlete Triad. Additional research is needed to further clarify and quantify this association. The Female and Male Athlete Triad Coalition Consensus Statements include evidence statements developed after a roundtable of experts held in conjunction with the American College of Sports Medicine 64th Annual Meeting in Denver, Colorado, in 2017 and are in 2 parts-Part I: Definition and Scientific Basis and Part 2: The Male Athlete Triad: Diagnosis, Treatment, and Return-to-Play. In this first article, we discuss the scientific evidence to support the Male Athlete Triad model.

Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): Shared Pathways, Symptoms and Complexities

The symptom similarities between training-overload (with or without an Overtraining Syndrome (OTS) diagnosis) and Relative Energy Deficiency in Sport (RED-S) are significant, with both initiating from a hypothalamic-pituitary origin, that can be influenced by low carbohydrate (CHO) and energy availability (EA). In this narrative review we wish to showcase that many of the negative outcomes of training-overload (with, or without an OTS diagnosis) may be primarily due to misdiagnosed under-fueling, or RED-S, via low EA and/or low CHO availability. Accordingly, we undertook an analysis of training-overload/OTS type studies that have also collected and analyzed for energy intake (EI), CHO, exercise energy expenditure (EEE) and/or EA. Eighteen of the 21 studies (86%) that met our criteria showed indications of an EA decrease or difference between two cohorts within a given study (n = 14 studies) or CHO availability decrease (n = 4 studies) during the training-overload/OTS period, resulting in both training-overload/OTS and RED-S symptom outcomes compared to control conditions. Furthermore, we demonstrate significantly similar symptom overlaps across much of the OTS (n = 57 studies) and RED-S/Female Athlete Triad (n = 88 studies) literature. It is important to note that the prevention of under-recovery is multi-factorial, but many aspects are based around EA and CHO availability. Herein we have demonstrated that OTS and RED-S have many shared pathways, symptoms, and diagnostic complexities. Substantial attention is required to increase the knowledge and awareness of RED-S, and to enhance the diagnostic accuracy of both OTS and RED-S, to allow clinicians to more accurately exclude LEA/RED-S from OTS diagnoses.

Long-Term Weight Loss Strategies for Obesity

CONTEXT

Obesity is a chronic disease that is difficult to manage without holistic therapy. The therapeutic armamentarium for obesity primarily consists of 4 forms of therapy: lifestyle modification (ie, diet and exercise), cognitive behavioral therapy, pharmacotherapy, and bariatric surgery.

EVIDENCE ACQUISITION

Evidence was consolidated from randomized controlled trials, observational studies, and meta-analyses.

EVIDENCE SYNTHESIS

After 2 years, lifestyle interventions can facilitate weight loss that equates to ~5%. Even though lifestyle interventions are plagued by weight regain, they can have substantial effects on type 2 diabetes and cardiovascular disease risk. Although 10-year percentage excess weight loss can surpass 50% after bariatric surgery, weight regain is likely. To mitigate weight regain, instituting a multifactorial maintenance program is imperative. Such a program can integrate diet, exercise, and pharmacotherapy. Moreover, behavioral therapy can complement a maintenance program well.

CONCLUSIONS

Obesity is best managed by a multidisciplinary clinical team that integrates diet, exercise, and pharmacotherapy. Bariatric surgery is needed to manage type 2 diabetes and obesity in select patients.

Prospective associations between physical activity and BMI with irregular periods and heavy menstrual bleeding in a large cohort of Australian women

STUDY QUESTION

Are physical activity (PA) and body mass index (BMI) associated with irregular periods and heavy menstrual bleeding (HMB) in Australian women?

SUMMARY ANSWER

Overweight and obese women have higher odds of both irregular periods and HMB than underweight/normal-weight women, but high levels of PA reduce the odds of HMB.

WHAT IS KNOWN ALREADY

Most studies on relationships between PA and menstrual problems have focused on female athletes, but there have been few population-based studies.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study, 10618 participants in the Australian Longitudinal Study of Women's Health (ALSWH) who completed mailed surveys in 1996, with follow-ups in 2000, 2003, 2006, 2009, 2012, and 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were aged 22 to 27 in 2000. They were asked to report their PA levels and the frequency of irregular periods and HMB in each survey. BMI was calculated at every survey from self-reported weight and height. Generalised estimating equation population-averaged model analyses were conducted to calculate odds ratios (OR) and 95% confidence intervals (95% CIs).

MAIN RESULTS AND THE ROLE OF CHANCE

At age 22 to 27 years, the prevalence of irregular periods was 19.4%. This remained stable over 15 years. There were no associations between PA and irregular periods. Overweight and obese women had higher odds of irregular periods [overweight: OR 1.08, (95% CI 1.00-1.17); obese: OR 1.29, (95%CI 1.18-1.41)] than women who were underweight/normal weight.The prevalence of HMB at age 22-27 years was 15.9%; this doubled over 15 years. Women who were highly active had 10% lower odds of HMB than women who reported no PA [OR 0.90, (95%CI 0.82-0.98)]. Overweight and obese women had higher odds of HMB [overweight: OR 1.15, (95%CI 1.07-1.23); obese: OR 1.37, (95%CI 1.26-1.49)] than women who were underweight/normal weight. Among obese women, high levels of PA were associated with 19% [OR 0.81, (95%CI 0.68-0.97)] reduction in the odds of HMB.

LIMITATIONS, REASONS FOR CAUTION

Data collected in the ALSWH are self-reported, which may be subject to recall bias. Reverse causation, due to menstrual problems impacting PA, is possible although sensitivity analyses suggest this is unlikely to have affected the results. Other conditions, e.g., polycystic ovary syndrome, for which no or incomplete data were available, could have affected the results.

WIDER IMPLICATIONS OF THE FINDINGS

Intervention studies are needed to assess the effect of increasing PA in women with HMB, but these preliminary findings suggest that promoting PA could be an affordable and feasible strategy for reducing HMB in young adult women.

STUDY FUNDING/COMPETING INTEREST(S)

The ALSWH is funded by the Australian Government. Funding for these analyses was provided by a University of Queensland (UQ) International Postgraduate Research Scholarship and a UQ International Development Fellowship. The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Low energy availability in female athletes: From the lab to the field

Decades of laboratory research have shown impairments to several body systems after only 4-5 days of strictly controlled consistent low energy availability (LEA); where energy availability (EA) = Energy Intake (EI) - Exercise Energy Expenditure (EEE)/Fat-Free Mass. Meanwhile, cross-sectional reports exist on the interrelatedness of LEA, menstrual dysfunction and impaired bone health in females (the Female Athlete Triad). These findings have demonstrated that LEA is the key underpinning factor behind a broader set of health and performance outcomes, recently termed as Relative Energy Deficiency in Sport (RED-S). There is utmost importance of early screening and diagnosis of RED-S to avoid the development of severe negative health and performance outcomes. However, a significant gap exists between short-term laboratory studies and cross-sectional reports, or clinically field-based situations, of long-term/chronic LEA and no definitive, validated diagnostic tests for RED-S exist. This review aims to highlight methodological challenges related to the assessment of the components of EA equation in the field (e.g. challenges with EI and EEE measures). Due to the uncertainty of these parameters, we propose the use of more chronic "objective" markers of LEA (i.e. blood markers). However, we note that direct extrapolations of laboratory-based outcomes into the field are likely to be problematic due to potentially poor ecological validity and the extreme variability in most athlete's daily EI and EEE. Therefore, we provide a critical appraisal of the scientific literature, highlighting research gaps, and a potential set of leading objective RED-S markers while working in the field.HIGHILIGHTS Direct application of short-term laboratory-based findings in the field is problematic.Calculation of energy availability (EA) in the field is methodologically challenging and prone to errors.The use of several biomarkers may allow the detection of early exposure to low EA in the female athlete.

Low energy availability: history, definition and evidence of its endocrine, metabolic and physiological effects in prospective studies in females and males

Energy availability (EA) is defined as the amount of dietary energy available to sustain physiological function after subtracting the energetic cost of exercise. Insufficient EA due to increased exercise, reduced energy intake, or a combination of both, is a potent disruptor of the endocrine milieu. As such, EA is conceived as a key etiological factor underlying a plethora of physiological dysregulations described in the female athlete triad, its male counterpart and the Relative Energy Deficiency in Sport models. Originally developed upon female-specific physiological responses, this concept has recently been extended to males, where experimental evidence is limited. The majority of data for all these models are from cross-sectional or observational studies where hypothesized chronic low energy availability (LEA) is linked to physiological maladaptation. However, the body of evidence determining causal effects of LEA on endocrine, and physiological function through prospective studies manipulating EA is comparatively small, with interventions typically lasting ≤ 5 days. Extending laboratory-based findings to the field requires recognition of the strengths and limitations of current knowledge. To aid this, this review will: (1) provide a brief historical overview of the origin of the concept in mammalian ecology through its evolution of algebraic calculations used in humans today, (2) Outline key differences from the ‘energy balance’ concept, (3) summarise and critically evaluate the effects of LEA on tissues/systems for which we now have evidence, namely: hormonal milieu, reproductive system endocrinology, bone metabolism and skeletal muscle; and finally (4) provide perspectives and suggestions for research upon identified knowledge gaps.

Recovery of menses after functional hypothalamic amenorrhoea: if, when and why

BACKGROUND

Prolonged amenorrhoea occurs as a consequence of functional hypothalamic amenorrhoea (FHA) which is most often induced by weight loss, vigorous exercise or emotional stress. Unfortunately, removal of these triggers does not always result in the return of menses. The prevalence and conditions underlying the timing of return of menses vary strongly and some women report amenorrhoea several years after having achieved and maintained normal weight and/or energy balance. A better understanding of these factors would also allow improved counselling in the context of infertility. Although BMI, percentage body fat and hormonal parameters are known to be involved in the initiation of the menstrual cycle, their role in the physiology of return of menses is currently poorly understood. We summarise here the current knowledge on the epidemiology and physiology of return of menses.

OBJECTIVE AND RATIONALE

The aim of this review was to provide an overview of (i) factors determining the recovery of menses and its timing, (ii) how such factors may exert their physiological effects and (iii) whether there are useful therapeutic options to induce recovery.

SEARCH METHODS

We searched articles published in English, French or German language containing keywords related to return of menses after FHA published in PubMed between 1966 and February 2020. Manuscripts reporting data on either the epidemiology or the physiology of recovery of menses were included and bibliographies were reviewed for further relevant literature. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria served to assess quality of observational studies.

OUTCOMES

Few studies investigate return of menses and most of them have serious qualitative and methodological limitations. These include (i) the lack of precise definitions for FHA or resumption of menses, (ii) the use of short observation periods with unsatisfactory descriptions and (iii) the inclusion of poorly characterised small study groups. The comparison of studies is further hampered by very inhomogeneous study designs. Consequently, the exact prevalence of resumption of menses after FHA is unknown. Also, the timepoint of return of menses varies strongly and reliable prediction models are lacking. While weight, body fat and energy availability are associated with the return of menses, psychological factors also have a strong impact on the menstrual cycle and on behaviour known to increase the risk of FHA. Drug therapies with metreleptin or naltrexone might represent further opportunities to increase the chances of return of menses, but these require further evaluation.

WIDER IMPLICATIONS

Although knowledge on the physiology of return of menses is presently rudimentary, the available data indicate the importance of BMI/weight (gain), energy balance and mental health. The physiological processes and genetics underlying the impact of these factors on the return of menses require further research. Larger prospective studies are necessary to identify clinical parameters for accurate prediction of return of menses as well as reliable therapeutic options.

Eating behaviours related to psychological stress are associated with functional hypothalamic amenorrhoea in exercising women

Functional hypothalamic amenorrhoea (FHA) can occur due to the independent or combined effects of psychogenic and energetic stressors. In exercising women, research has primarily focused on energy deficiency as the cause of FHA while psychological stressors have been ignored. To assess both psychological and metabolic factors associated with FHA in exercising women, we performed across-sectional comparison of 61 exercising women (≥2 hours/week, age 18-35 years, BMI 16-25kg/m²), who were eumenorrheic or amenorrhoeic confirmed by daily urine samples assayed for reproductive hormone metabolites. Psychological factors and eating behaviours were assessed by self-report questionnaires. Exercising women with FHA had lower resting metabolic rate (p=0.023), T3 (p<0.001), T4 (p=0.013), leptin (p=0.002), higher peptide YY (p<0.001), greater drive for thinness (p=0.017), greater dietary cognitive restraint (p<0.001), and displayed dysfunctional attitudes, i.e., need for social approval (p=0.047) compared to eumenorrheic women. Amenorrhoeic women displayed asignificant positive correlation between the need for social approval and drive for thinness with indicators of stress, depression, and mood, which was not apparent in eumenorrheic women. In exercising women with FHA, eating behaviours are positively related to indicators of psychological stress and depression.

The effect of physical activity on reproductive health outcomes in young women: a systematic review and meta-analysis

BACKGROUND

In the context of increasing rates of overweight and obesity in young adult women, and the increasing numbers of women seeking help for fertility problems, it is important to understand whether physical activity (PA) could help with management of reproductive health problems, with or without weight loss.

OBJECTIVE AND RATIONALE

The primary aim of this systematic review and meta-analysis was to assess the effects of PA on selected reproductive health outcomes in young adult women, in order to inform best practice advice for women in terms of promoting fertility and reproductive health in young adulthood.

SEARCH METHODS

An electronic search of PubMed, EMBASE, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, Web of Science, SportDiscus, and Cochrane was performed for studies published between January 2000 and May 2018. Keywords and Medical Subject Headings terms related to PA, reproductive health, and weight gain were used. Studies were selected if they were intervention studies, if PA was delivered as part of an intervention to pre-menopausal women, and if any reproductive health outcome was reported. Quality analysis was performed using the Tool for the assEssment of Study qualiTy and reporting in EXercise.

OUTCOMES

Eighteen studies, with a mix of four types of study design (4 randomized controlled trials (RCTs), 11 randomized comparison trials, 2 non-randomized comparison trials, and 1 single-arm clinical trial), were identified. Comparisons included fertility treatment (four studies) and common treatments for women with polycystic ovary syndrome (PCOS) symptoms (nine studies). Pooled analysis of data from three of the four studies with a control group showed higher pregnancy [risk ratio (RR) 2.10, 95% CI (1.32, 3.35); three studies] and live birth [RR 2.11, 95% CI (1.02, 4.39); two studies] rates in the intervention groups compared with non-therapy controls. Aggregated data from the fertility treatment comparative studies (i.e. those that compared PA with standard fertility treatment such as clomiphene, gonadotrophins, and/or IVF) showed no significant intervention differences: RR 1.46, 95% CI (0.87, 2.45) for clinical pregnancy (four studies) and RR 1.09, 95% CI (0.56, 2.12) for live births (two studies). Pooled analysis from the comparison trials that used pharmaceutical or dietary treatment for PCOS as comparison showed higher pregnancy rates [RR 1.59, 95% CI (1.06, 2.38); five studies] and live birth rates [RR 2.45, 95% CI (1.24, 4.83); two observations] in the PA intervention groups than in the comparison groups. Analysis of other outcomes, such as ovulation rates, menstrual regularity, and conception rates, showed no differences between the PA intervention and comparison groups.

WIDER IMPLICATIONS

There is emerging evidence from RCT that PA may improve pregnancy rates in women with reproductive health problems. Comparative studies indicate that PA intervention may be as effective as other commonly used clinical intervention strategies for improving reproductive health outcomes. While the type, intensity, frequency, and duration of optimal PA intervention, and the role of PA independent of weight loss, remain unclear, these preliminary findings suggest that PA may be an affordable and feasible alternative or complementary therapy to fertility treatments.

Low Energy Availability in Athletes 2020: An Updated Narrative Review of Prevalence, Risk, Within-Day Energy Balance, Knowledge, and Impact on Sports Performance

Low energy availability (EA) underpins the female and male athlete triad and relative energy deficiency in sport (RED-S). The condition arises when insufficient calories are consumed to support exercise energy expenditure, resulting in compromised physiological processes, such as menstrual irregularities in active females. The health concerns associated with longstanding low EA include menstrual/libido, gastrointestinal and cardiovascular dysfunction and compromised bone health, all of which can contribute to impaired sporting performance. This narrative review provides an update of our previous review on the prevalence and risk of low EA, within-day energy deficiency, and the potential impact of low EA on performance. The methods to assess EA remain a challenge and contribute to the methodological difficulties in identifying “true” low EA. Screening female athletic groups using a validated screening tool such as the Low Energy Availability in Females Questionnaire (LEAF-Q) has shown promise in identifying endurance athletes at risk of low EA. Knowledge of RED-S and its potential implications for performance is low among coaches and athletes alike. Development of sport and gender-specific screening tools to identify adolescent and senior athletes in different sports at risk of RED-S is warranted. Education initiatives are required to raise awareness among coaches and athletes of the importance of appropriate dietary strategies to ensure that sufficient calories are consumed to support training.

Energy Availability Is Associated With Luteinizing Hormone Pulse Frequency and Induction of Luteal Phase Defects

OBJECTIVE

Determine the interrelations between reductions in energy availability (EA), luteinizing hormone (LH) pulse frequency, and the induction of menstrual disturbances in previously sedentary, ovulatory women.

METHODS

Secondary analysis of a randomized controlled trial consisting of a 3-month controlled diet and supervised exercise program. EA was calculated daily by measured energy intake (kcal) and exercise energy expenditure (kcal) normalized to fat-free mass (kg) and averaged during baseline and each of 3 intervention menstrual cycles. Blood samples were obtained every 10 minutes for 24 hours in the early follicular phase before the intervention and after 3 months of diet and exercise (n = 14). LH pulse dynamics were assessed by Cluster. Linear mixed models determined whether EA predicts LH pulse frequency and LH pulse frequency predicts luteal phase defects (LPDs).

RESULTS

Subjects were 20 ± 1 years old, 165.1 ± 1.4 cm tall, and weighed 58.9 ± 1.5 kg. LH pulse frequency decreased from 0.82 ± 0.06 pulses/h to 0.63 ± 0.09 pulses/h (P = 0.048) as a result of the intervention which produced modest (-3.2 ± 0.6 kg) weight loss. EA, averaged across a menstrual cycle, predicted LH pulse frequency (P = 0.003) such that a single-unit decrease in EA was associated with a 0.017 pulses/h decrease in LH pulse frequency. LH pulse frequency in cycles with LPDs was 49% of that observed in cycles with no menstrual disturbances and for every 0.1-unit decrease in LH pulse frequency, the odds of having an LPD were 22× greater than having an optimal ovulatory cycle (P = 0.01).

CONCLUSIONS

Modest reductions in EA over a prolonged period are associated with decreased LH pulse frequency and the induction of menstrual disturbances.

Indices of Resting Metabolic Rate Accurately Reflect Energy Deficiency in Exercising Women

Energy deficiency in exercising women can lead to physiological consequences. No gold standard exists to accurately estimate energy deficiency, but measured-to-predicted resting metabolic rate (RMR) ratio has been used to categorize women as energy deficient. The purpose of the study was to (a) evaluate the accuracy of RMR prediction methods, (b) determine the relationships with physiological consequences of energy deficiency, and (c) evaluate ratio thresholds in a cross-sectional comparison of ovulatory, amenorrheic, or subclinical menstrual disturbances in exercising women (n = 217). Dual-energy X-ray absorptiometry (DXA) and indirect calorimetry provided data on anthropometrics and energy expenditure. Harris–Benedict, DXA, and Cunningham (1980 and 1991) equations were used to estimate RMR and RMR ratio. Group differences were assessed (analysis of variance and Kruskal–Wallis tests); logistic regression and Spearman correlations related ratios with consequences of energy deficiency (i.e., low total triiodothyronine; TT3). Sensitivity and specificity calculations evaluated ratio thresholds. Amenorrheic women had lower RMR (p < .05), DXA ratio (p < .01), Cunningham1980 (p < .05) and Cunningham1991 (p < .05) ratio, and TT3 (p < .01) compared with the ovulatory group. Each prediction equation overestimated measured RMR (p < .001), but predicted (p < .001) and positively correlated with TT3 (r = .329–.453). A 0.90 ratio threshold yielded highest sensitivity for Cunningham1980 (0.90) and Harris–Benedict (0.87) methods, but a higher ratio threshold was best for DXA (0.94) and Cunningham1991 (0.92) methods to yield a sensitivity of 0.80. In conclusion, each ratio predicted and correlated with TT3, supporting the use of RMR ratio as an alternative assessment of energetic status in exercising women. However, a 0.90 ratio cutoff is not universal across RMR estimation methods.