13. Dietary strategies contributing to low energy availability in exercising women: underlying physiology and impact on the menstrual cycle

Loucks, A. B., M. Verdun, and E. M. Heath. Low energy availability, not stress of exercise, alters LH pulsatility in exercising women. J. Appl. Physiol.84(1): 37–46, 1998.—We tested two hypotheses about the disruption of luteinizing hormone (LH) pulsatility in exercising women by assaying LH in blood samples drawn at 10-min intervals over 24 h from nine young, habitually sedentary, regularly menstruating women on days 8, 9, or 10 of two menstrual cycles after 4 days of intense exercise [E = 30 kcal ⋅ kg lean body mass (LBM)−1 ⋅ day−1at 70% of aerobic capacity]. To test the hypothesis that LH pulsatility is disrupted by low energy availability, we controlled the subjects’ dietary energy intakes (I) to set their energy availabilities (A = I − E) at 45 and 10 kcal ⋅ kg LBM−1 ⋅ day−1during the two trials. To test the hypothesis that LH pulsatility is disrupted by the stress of exercise, we compared the resulting LH pulsatilities to those previously reported in women with similar controlled energy availability who had not exercised. In the exercising women, low energy availability reduced LH pulse frequency by 10% ( P < 0.01) during the waking hours and increased LH pulse amplitude by 36% ( P = 0.05) during waking and sleeping hours, but this reduction in LH pulse frequency was blunted by 60% ( P = 0.03) compared with that in the previously studied nonexercising women whose low energy availability was caused by dietary restriction. The stress of exercise neither reduced LH pulse frequency nor increased LH pulse amplitude (all P > 0.4). During exercise, the proportion of energy derived from carbohydrate oxidation was reduced from 73% while A = 45 kcal ⋅ kg LBM−1 ⋅ day−1to 49% while A = 10 kcal ⋅ kg LBM−1 ⋅day−1( P < 0.0001). These results contradict the hypothesis that LH pulsatility is disrupted by exercise stress and suggest that LH pulsatility in women depends on energy availability.

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Evidence for a Causal Role of Low Energy Availability in the Induction of Menstrual Cycle Disturbances During Strenuous Exercise Training

Obstetrical & Gynecological Survey ◽

10.1097/00006254-200207000-00017 ◽

2002 ◽

Vol 57 (7) ◽

pp. 440-442

Author(s):

Nancy I. Williams ◽

Dana L. Helmreich ◽

David B. Parfitt ◽

Anne Caston-Balderrama ◽

Judy L. Cameron

Keyword(s):

Menstrual Cycle ◽

Exercise Training ◽

Low Energy ◽

Causal Role ◽

Strenuous Exercise ◽

Energy Availability ◽

Low Energy Availability

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Clinical application of monitoring indicators of female dancer health, including application of artificial intelligence in female hormone networks

10.1101/2021.09.27.21264119 ◽

2021 ◽

Author(s):

Nicola Keay ◽

Martin Lanfear ◽

Gavin Francis

Keyword(s):

Artificial Intelligence ◽

Menstrual Cycle ◽

Clinical Application ◽

Low Energy ◽

List Type ◽

Energy Availability ◽

Clinical Tool ◽

Female Hormone ◽

Network Function ◽

Low Energy Availability

AbstractObjectivesThe purpose of this study was to assess the effectiveness of monitoring professional female dancer health with a variety of subjective and objective monitoring methods, including application of artificial intelligence (AI) techniques to modelling menstrual cycle hormones and delivering swift personalised clinical advice.MethodsFemale dancers from a ballet company completed a published online dance-specific health questionnaire. Over the study period, dancers recorded wellbeing and training metrics, with menstrual cycle tracking and blood tests. For menstrual cycle hormones AI-based techniques modelled hormone variation over a cycle, based on capillary blood samples taken at two time points. At regular, virtual, clinical interviews with each dancer, findings were discussed, and personalised advice given.Results14 female dancers (mean age 25.5 years, SD 3.7) participated in the study. 10 dancers recorded positive scores on the dance health questionnaire, suggesting a low risk of relative energy deficiency in sport (RED-S). 2 dancers were taking hormonal contraception. Apart from 1 dancer, those not on hormonal contraception reported current eumenorrhoeic status. The initiative of monitoring menstrual cycles and application of AI to model menstrual cycle hormones found that subclinical hormone disruption was occurring in 6 of the 10 dancers reporting regular cycles. 4 of the 6 dancers who received personalised advice, showed improved menstrual hormone function, including one dancer who had planned pregnancy.ConclusionsMultimodal monitoring facilitated delivery of prompt personalised clinical medical feedback specific for dance. This strategy enabled the early identification and swift management of emergent clinical issues. These innovations received positive feedback from the dancers.Summary boxesWhat are the new findings?Monitoring female dancers with a variety of interactive methods – dance specific questionnaire, online tracking and blood testing – together with individual clinical discussion, facilitates comprehensive, personalised support for dancer health.The clinical application of artificial intelligence (AI) techniques to endocrine function provides the finer detail of female hormone network function.This novel approach to monitoring dynamic hormone function enabled the detection of subtle female hormone dysfunction as a result of changes in training and nutrition patterns, which occurred before change in menstruation pattern from menstrual tracking.This multifaceted clinical approach was also effective and helpful in supporting dancers restore full hormone network function through personalised training and nutritional strategies.How might this study impact on clinical practice in the future?Personalised, dance specific health advice based on subjective and objective measures can support sustainable individual dancer health.Clinical application of artificial intelligence (AI) to menstrual cycle hormones can provide a dynamic and complete picture of hormone network function, without the need to do daily blood tests to measure all four key menstrual cycle hormones.This AI approach to modelling hormones enables early detection of subtle, subclinical endocrine dysfunction due to low energy availability in female exercisers. This clinical tool can also facilitate the close clinical monitoring of the restoration of full hormone network function in recovery from low energy availability.Using AI to model female hormones can be an important clinical tool for female athletes, including those athletes where it is difficult to distinguish between perimenopause symptoms and those associated with low energy availability.

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The Science of Healthy Menstruation in Exercising Women

Kinesiology Review ◽

10.1123/kr.2016-0041 ◽

2017 ◽

Vol 6 (1) ◽

pp. 78-90 ◽

Cited By ~ 1

Author(s):

Nancy I. Williams ◽

Clara V. Etter ◽

Jay L. Lieberman

Keyword(s):

Poor Performance ◽

Low Energy ◽

Energy Deficit ◽

Future Research ◽

Energy Availability ◽

Dietary Practices ◽

Exercising Women ◽

Key Factor ◽

Low Energy Availability ◽

Menstrual Disturbances

An understanding of the health consequences of abnormal menstrual function is an important consideration for all exercising women. Menstrual disturbances in exercising women are quite common and range in severity from mild to severe and are often associated with bone loss, low energy availability, stress fractures, eating disorders, and poor performance. The key factor that causes menstrual disturbances is low energy availability created by an imbalance of energy intake and energy expenditure that leads to an energy deficit and compensatory metabolic adaptations to maintain energy balance. Practical guidelines for preventing and treating amenorrhea in exercising women include evidence-based dietary practices designed to achieve optimal energy availability. Other factors such as gynecological age, genetics, and one’s susceptibility to psychological stress can modify an individual’s susceptibility to menstrual disturbances caused by low energy availability. Future research should explore the magnitude of these effects in an effort to move toward more individualized prevention and treatment approaches.

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Evidence for a Causal Role of Low Energy Availability in the Induction of Menstrual Cycle Disturbances during Strenuous Exercise Training

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.86.11.8024 ◽

2001 ◽

Vol 86 (11) ◽

pp. 5184-5193 ◽

Cited By ~ 143

Author(s):

Nancy I. Williams ◽

Dana L. Helmreich ◽

David B. Parfitt ◽

Anne Caston-Balderrama ◽

Judy L. Cameron

Keyword(s):

Menstrual Cycle ◽

Exercise Training ◽

Low Energy ◽

Causal Role ◽

Strenuous Exercise ◽

Energy Availability ◽

Low Energy Availability

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Body Composition, Dietary Intake and the Risk of Low Energy Availability in Elite-Level Competitive Rhythmic Gymnasts

Nutrients ◽

10.3390/nu13062083 ◽

2021 ◽

Vol 13 (6) ◽

pp. 2083

Author(s):

María Villa ◽

José G. Villa-Vicente ◽

Jesus Seco-Calvo ◽

Juan Mielgo-Ayuso ◽

Pilar S. Collado

Keyword(s):

Body Composition ◽

Dietary Intake ◽

Body Fat ◽

Low Energy ◽

Energy Availability ◽

Future Health ◽

Elite Level ◽

Low Energy Availability ◽

Rhythmic Gymnasts ◽

Recommended Level

The aim of this study was to analyze dietary intake and body composition in a group of elite-level competitive rhythmic gymnasts from Spain. We undertook body composition and nutritional analysis of 30 elite gymnasts, divided into two groups by age: pre-teen (9–12 years) (n = 17) and teen (13–18 years) (n = 13). Measures of height, weight, and bioimpedance were used to calculate body mass index and percent body fat. Energy and nutrient intakes were assessed based on 7-day food records. The two groups had similar percentages of total body fat (pre-teen: 13.99 ± 3.83% vs. teen: 14.33 ± 5.57%; p > 0.05). The energy availability values for pre-teens were above the recommended values (>40 kcal/FFM/day) 69.38 ± 14.47 kcal/FFM/day, while those for the teens were much lower (34.7 ± 7.5 kcal/FFM/day). The distribution of the daily energy intake across the macronutrients indicates that both groups ingested less than the recommended level of carbohydrates and more than the recommended level of fat. Very low intakes of calcium and vitamin D among other micronutrients were also noted. The main finding is that teenage gymnasts do not consume as much energy as they need each day, which explains their weight and development. Moreover, they are at a high risk of developing low energy availability that could negatively impact their performance and future health.

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