"Exercising Metabolism in Female Athletes with Low Energy Availability" by Marissa Reshma Shahani

Award Date

12-1-2024

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Interdisciplinary Programs

First Committee Member

Thessa Hilgenkamp

Second Committee Member

Sara Rosenkranz

Third Committee Member

John Mercer

Fourth Committee Member

Samantha John

Number of Pages

97

Abstract

BACKGROUND. Low Energy Availability (LEA) is known to affect female athletes at significantly greater rates than male athletes and has unique consequences pertaining to female physiology such as the menstrual cycle, as well as deleterious effects on other organ systems. LEA has been implicated in the onset of cardiovascular diseases and increased cardiovascular risk, the presence of mental health disorders including depression and anxiety, altered energy storage, and increased rates of injury and illness. A particular age group of female athletes, young adults in college, are at an even higher risk of developing LEA compared to females of other age groups. This age (18–24 years) makes this population especially vulnerable to under-fueling, either by intentional restriction of calories or due to lack of food knowledge or access. Because this stage of life is also vital for creating a foundation of healthy habits that continue into adulthood, it is imperative to address these habits and understand the physiological and psychological effects under-fueling can have on these athletes. While many of the effects of LEA on health have been studied in detail over the last decade, some relationships are still not well understood. Studies in individuals with LEA have observed altered glycogen storage compared to those without LEA, which may alter their energy sources during exercise. Additionally, the known effects of LEA on cardiac structure and function indicate a potential effect on blood pressure which has been minimally investigated. Lastly, the relationship between LEA and depression has been observed in numerous studies. However, given the fact that college students are more likely to experience depression than other age groups warrants a deeper look into this relationship specifically within college-aged female athletes due to their elevated risk of both depression and LEA.

AIMS. The overall aim of this dissertation was to further investigate the relationship between LEA and metabolism, cardiovascular health, and mental health in NCAA Division I female athletes. The first specific aim was to determine whether substrate utilization at various exercise intensities in individuals with LEA was altered compared to those without LEA. The second specific aim was to investigate the potential relationship between LEA and blood pressure. The final aim of this dissertation was to determine the relationship between LEA and depression in this population.

METHODS. An observational study was designed to address the specific aims. NCAA Division I female athletes (ages 18–24) from numerous sports teams were recruited. They were assessed for LEA using the LEAF-Q, which has been validated to determine current energy availability status in female athletes. They then participated in the collection of resting blood pressure measurements as well as a treadmill protocol. The treadmill protocol was designed to include three three-minute intervals at 60%, 70%, and 80% of the participant's VO2peak respectively. VO2 and VCO2 were measured during the treadmill protocol and used to calculate the oxidation rates of carbohydrates and fat at the different intensities. Participants also completed a General Health Questionnaire-12 (GHQ-12), which has been validated for determining the presence of depressive symptoms.

RESULTS. No differences were observed in carbohydrate or fat oxidation rates between participants with LEA and participants without LEA. Neither a relationship between LEA and blood pressure nor a relationship between LEA and depression was supported by the findings of this dissertation.

CONCLUSIONS. In this population of NCAA Division I female athletes, there were no differences in substrate utilization, blood pressure, or GHQ-12 scores between those with LEA and those without LEA. However, these findings may be different than we hypothesized due to the specific population chosen, as the hypotheses were based on studies completed in primarily elite athletes of a broader age range.

Keywords

Blood Pressure; Female Athlete; Low Energy Availability; Mental Health; Metabolism

Disciplines

Kinesiology | Nutrition

File Format

PDF

File Size

1,094 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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Available for download on Wednesday, December 15, 2027


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