Sex Hormones, Exercise and Women: Scientific and Clinical Aspects

Description:

Now in a revised and expanded second edition including seven brand new chapters, this book compiles and synthesizes the latest research and clinical evidence regarding the intricate relationship between sex hormones and the physical activity level and overall health of the female endocrine system across the lifespan.

  Expert authors from around the world discuss in detail the impact of sex hormones on energy metabolism, cardiorespiratory system, nervous system, and musculoskeletal health, as well as environmental and psychological factors affecting exercise and sexual health. Considerations of the hormonal and physiological changes to the menstrual cycle and in menopause due to exercise receive chapters of their own. New to this edition are discussions of pregnancy, menopause, aerobic endurance training, the transgender athlete, sports performance, and the future of sports and exercise science relating to the active female.   Covering a hot topic in sports medicine and science, Sex Hormones, Exercise and Women, Second Edition will be of interest to researchers, clinicians, exercise scientists, and residents and fellows in these areas.

Preface

In the late 1970s, medical science was beginning to understand that exercise training, while normally an extremely positive physiological stimulus, could also have some drawbacks. Landmark research studies by scientists such as Dr. Barbara Drinkwater, Dr. Anne Loucks, and Dr. Michelle Warren, as well as others, demonstrated that exercise training could be a causative factor in disrupting the endocrine control of a woman’s reproductive system leading to the development of “athletic amenorrhea” (secondary amenorrhea). This medical condition is now recognized as part of the conditions associated with the Female Athlete Triad.

The basic premise of the research work on the development of athletic amenorrhea in women can be conceptualized as follows:

Exercise → Female Reproductive Hormones → Physiologic Consequences (negative)

That is, aspects of exercise and exercise training modulate the functioning of the female reproductive hormones. This modulating influence can be highly negative, leading to low estrogen and progesterone states and disruption of normal ovary function and menstruation. Contemporary research has demonstrated that the critical aspects initiating the sequence of such events are energy availability (i.e., development of a low energy availability state; recently designated as part of the Relative Energy Deficiency in Sports condition [RED-S] by an International Olympic Committee Medical Commission).

As a young professional, I found the research on athletic amenorrhea an exciting and fascinating aspect of exercise endocrinology. But my curiosity also caused me to think about the relationship in a different fashion and ask the question—if exercise affects reproductive hormones, could the reproductive hormones have physiological effects unrelated to reproduction that influences the capacity of women to exercise? This seemed a logical question to me as many hormones have more than one physiological effect/impact, and structurally many reproductive hormones have chemical structures similar to many metabolic and water balance hormones. In other words, I wondered:

Female Reproductive Hormones → Exercise → Physiologic Consequences (negative/positive?)

After studying the research literature, it was apparent that animal researchers had been asking this question and seeing that the female reproductive hormones did affect physiological systems and processes that affected exercise capacity. At that time, nearly 40 years ago, the human-based literature was extremely sparse. With that, I and a number of other researchers began to pursue the question of whether the female reproductive hormones have physiological impacts on the bodily systems that are essential to the exercise capacity of women exercisers.

In asking this question, to myself, the underlying premise was not to examine women in order to see why in some activities men are better. But, more to understanding the unique physiology of women and whether female sex hormones might account for some of the variance in physiological performance between amenorrheic and eumenorrheic women, and within women across the life span as they experience menarche to menopause. That has been my interest in pursuing this absorbing topic and why I wanted to develop this book.

This book was developed with the hope that the select group of professionals writing the various chapters could address this last question. Like nearly all written works, this one could be improved and be made better, but I am extremely proud and thankful to the international collection of authors who contributed and put forth so much hard work. Each discussed topic provides current insight into the state-of-theart research in the respective topic area. It is hoped the reader will be as excited and fascinated after reading the individual topics as the authors were in writing them. I also hope the insights provided herein will inspire new researchers to ask questions about the roles of female sex hormones in exercise and pursue investigations to seek answers to those questions.

Table of contents :

Preface

Prologue
Contents
Contributors
1 The Hypothalamic–Pituitary–Ovarian Axis, Menstrual and Oral Contraceptive Cycles: Regulation and Function in the Context of Exercise and Sport
Introduction
Female Sex Steroids
Estrogens
Progestogen
Hypothalamic–Pituitary–Ovarian Axis
Hypothalamic Hormones
Pituitary Hormones
Ovarian Hormones
Other Key Regulators of the HPO Axis
The Menstrual Cycle
Menstrual cycle, sport and exercise
Menstrual Dysfunction
Hormonal Contraceptives
Oral Contraceptives
Estrogens
Progestins
Progestogen-Only Hormonal Contraceptives
Intrauterine Devices (IUDs)
Possible Side Effects and Adverse Effects of Hormonal Contraceptives
Non-contraceptive Benefits of HCs
Non-hormonal Contraceptive Methods
Hormonal Contraceptives and Exercise—Sport
Female Hormones in the Laboratory and on the Field
Summary and Conclusions
References
2 Sex Hormones and Substrate Metabolism During Endurance Exercise
Introduction
Sex Differences in Substrate Metabolism During Endurance Exercise
Carbohydrate Metabolism
Fat Metabolism
Estrogen-Induced Sex Differences in Substrate Metabolism
Protein Metabolism
Menstrual Cycle and Substrate Metabolism During Endurance Exercise
Fluctuations of Ovarian Hormones During the Menstrual Cycle
Natural Ovarian Hormones and Substrate Metabolism During Endurance Exercise
Oral Contraceptive Effects on Substrate Metabolism During Endurance Exercise
Oral Contraceptive Formulations
Synthetic Ovarian Hormone Affects on Substrate Metabolism During Endurance Exercise
Pregnancy
Menopause Affects on Substrate Metabolism During Endurance Exercise
Menopause
Sex Differences in Substrate Metabolism During Endurance Exercise in Older Individuals
Menopause and Substrate Metabolism During Endurance Exercise: Comparison Between Pre- and Postmenopausal Women
Menopause, Hormone Replacement Therapy, and Substrate Metabolism During Endurance Exercise
Conclusion
References
3 Effects of Sex Hormones and Exercise on Adipose Tissue
Overview of Functions of Adipose Tissue
Effects of Exercise and Estrogen on Adipocyte Lipolysis
Factors Affecting Adipose Tissue Distribution
Role of Estrogen Receptors in Adipose Tissue Metabolism
Effects of Exercise and Estrogen on Brown Adipose Tissue (BAT)
Mitochondrial Function and Browning of WAT (Can Exercise and Estrogen Make Fat Cells Fit?)
Roles Played by Exercise and Estrogen in Adiposity Reduction
Adipose Tissue as an Endocrine Organ Susceptible to Inflammation
Effects of Exercise and Estrogen on Adipose Tissue Inflammation
Role of Sex in Exercise-Mediated Adipose Tissue Responses
Summary
References
4 Sex Hormones and Their Impact on the Respiratory Responses to Exercise and the Environment
Introduction
Effect of Sex and Sex Hormones on Resting and Exercise Ventilatory Parameters
Rest and Exercise Ventilation
Ventilatory Pattern and Respiratory Mechanics
Effect of Sex
Effect of Sex Hormones
Pulmonary Gas Exchange
Effect of Sex
Effect of Sex and Sex Hormones on Ventilatory Chemoresponsiveness
Effect of Sex
Hypoxic Ventilatory Response
Effect of Sex Hormones
Effect of OC Use
Hypercapnic Ventilatory Response
Effect of Sex Hormones
Effect of OC Use
Summary
References
5 Sex Hormones and Environmental Factors Affecting Exercise
Introduction
Controlling Hormonal Effects During Human Physiological Studies
Water Regulation
Sex Hormone Effects on Fluid Regulation
Exercise Effects on Fluid Balance
Sex Differences in Thermoregulation
Sex Hormone Effects Within Women During Exercise
Effects on Fluid and Electrolyte Requirements
Temperature Regulation and Fluid Balance: Special Populations
Aging and Menopause
Polycystic Ovary Syndrome
Conclusions
References
6 Sex Hormone Effects on the Nervous System and Their Impact on Muscle Strength and Motor Performance in Women
Introduction
Sex Hormones and Their Metabolites—A Dynamic Ecosystem
Do Sex Hormones and/or the Menstrual Cycle Phases Affect the Nervous System?
General Effects on the Nervous System
Sex Hormone/Menstrual Cycle Phase Effects on Motor Control in Humans
Do Sex Hormones/Menstrual Cycle Phases Affect Muscle Strength?
Do Sex Hormones/Menstrual Cycle Phases Affect Motor Performance?
Caveats: The “Normal Menstrual Cycle” and Hormonal Contraception
Conclusions
References
7 Estrogen and Menopause: Muscle Maintenance, Repair, Function, and Health
Introduction
Muscle Damage
Muscle Inflammation
Muscle Satellite Cells and Muscle Repair
Muscle Mass and Recovery from Atrophy
Muscle Strength
Hormone Replacement, Health, and Exercise in Older Women
Summary
References
8 The Effect of Sex Hormones on Ligament Structure, Joint Stability and ACL Injury Risk
Introduction
Complexity of Studying Hormone Profiles in Physically Active Females
Cycle Phase and Injury Risk
Effect of Sex Hormones on Collagen Metabolism, Tissue Remodeling, and Mechanical Properties
Effect on Collagen Metabolism
Effect on Mechanical Properties
Effect of Sex Hormones on Knee Joint Laxity
Sex Differences in Knee Laxity and ACL Injury Risk
Sex Hormone Effects on Knee Laxity
Contraceptive Hormones
Relaxin
Relaxin and Collagen Metabolism
Relaxin, Knee Laxity, and ACL Injury
Summary and Future Directions
References
9 Sex Hormones and Endurance Exercise in Women: Physiological and Psychological Factors Affecting Performance
Introduction
Female Sex Hormone Profiles
Effect of Female Sex Hormones on Endurance Exercise Events, Time Trials, and Field-Test Performances
Defining the Predictors of Endurance Exercise Performance
Peak Oxygen Uptake
Intensity Domain Thresholds
Exercise Economy
Achievement Behavior
Pain Tolerance
Effect of Female Sex Hormones on the Predictors of Endurance Exercise Performance
Peak Oxygen Uptake
Intensity Domain Thresholds
Exercise Economy
Achievement Behavior
Pain Tolerance
Effect of Female Sex Hormones on the Physiological Limiting Factors of Endurance Exercise Performance
Pulmonary Diffusion
Cardiac Output
Oxygen-Carrying Capacity
Muscle Characteristics
Effect of Female Sex Hormones on Other Factors Affecting Endurance Exercise Performance
Effect of Female Sex Hormones on Other Factors Affecting Endurance Exercise Performance
Summary
References
10 Sex Hormones, Menstrual Cycle, and Resistance Exercise
Introduction
Muscle Strength During the Menstrual Cycle
Anabolic Hormones and Resistance Exercise in Women
Hormonal Responses to Resistance Exercise During Different Menstrual Cycle Phases
Hormonal Responses to Resistance Exercise with Different Menstrual Cycle Status
Resistance Exercise-Induced Muscle Damage and Recovery During Different Menstrual Cycle Phases
Menstrual Cycle and Resistance Training Program
Conclusion
References
11 The Effect of the Menstrual Cycle on Exercise and Sports Performance
Introduction
The Menstrual Cycle
The Menstrual Cycle and Physiological Function
Mechanisms Potentially Altering Strength Performance Across the Menstrual Cycle
Measures of Strength Performance Across the Menstrual Cycle
Mechanisms Potentially Altering Endurance Performance Across the Menstrual Cycle
Endurance Performance Across the Menstrual Cycle
Overall Effect of the Menstrual Cycle on Exercise Performance
Practical Recommendations
References
12 Nutritional Strategies and Sex Hormone Interactions in Women
Introduction
Energy and Macronutrients
Habitual Diets
Nutrient Intake in the days Before Exercise
Nutrient Intake in the Hours Before Exercise
Nutrient Intake During Exercise
Fluids and Electrolytes
Thermoregulation and Body Fluids
Electrolyte Handling and Imbalances
Menopause, Aging, and Hydration
Summary
Estrogen and Antioxidants
Polyphenols
Soy and Isoflavones
(Blue-)Berries and Anthocyanins
Green Tea and Catechins
Other Polyphenol-Rich Foods and Diets
Fish Oil
Vitamin D and Calcium
Pre- and Probiotics
Branched Chain Amino Acids (BCAA)
Nutrients Versus Diet
Conclusions
References
13 Tracking Health and Fitness Variables in Females: Menstrual Cycle Considerations
Introduction
Menstrual Cycle Phase, Length, and Symptom Tracking—Why and How?
The Use of Technology for Tracking the Menstrual Cycle
Factors Influencing Cycle Characteristics
Menstrual History
Lifestyle Factors
Environmental Factors
Biological Factors
Summary
How the Menstrual Cycle May Affect Other Metrics in the Female Athlete
Potential Impact of Changes in Endogenous Hormones on Blood Biomarkers
How the Menstrual Cycle May Affect Markers of Readiness and Wellness
Other Considerations
Conclusions
References
14 Pregnancy, Sex Hormones, and Exercise
Introduction
Changes and Outcomes Associated with Pregnancy
Sex Hormones
Anatomical and Physiological
Functional Implications of Pregnancy on Exercise Performance and Capacity
Sex Hormones
Anatomical and Physiological
Practical Implications of Pregnancy on Exercise Performance and Capacity
Sex Hormones
Anatomical and Physiological
General Principles of Exercise Prescription During Pregnancy
The Fourth Trimester
Conclusions
References
15 Physiology of Menopause
Stages of Normal Reproductive Aging in Women
Physiological Changes Through Menopause
Metabolic and Cardiovascular Changes
Metabolic Alterations
Cardiometabolic and Cardiovascular Changes
Skeletal System Changes
Body Composition Changes
Functional and Quality of Life Changes
Racial/Ethnic Considerations
Summary
References
16 Can Exercise Improve Symptoms in Menopausal Women?
Introduction
The Benefits of Exercise
Exercise During Menopause
Vasomotor Symptoms
No Effects of Exercise on Vasomotor Symptoms
Exercise Decreases Hot Flushes
Exercise Improves Sleep Disturbances
Effects of Physical Activity on Vasomotor Symptoms and Metabolic Measures
Psychological Symptoms
Somatic Symptoms
Exercise Improves Somatic Symptoms in Menopausal Women
Sexual Symptoms
Expert Opinion
Inflammatory Markers and Menopause Symptoms
Exercise Improves Cardiometabolic Disease in Postmenopausal Women
Concluding Remarks
References
17 The Transgender Woman and Sport Performance
Introduction
Background—Transgender Individuals
Gender-Affirming Hormonal Therapy of Transgender Women
Transgender Women Affirming Surgery
Athletic Performance in the Transgender Athlete
Gaps of Knowledge on Sports Performance in Transgender Women
Athletic Performance in Transgender Women
Athletic Performance in Untrained Transgender Women
Athletic Performance in Trained Transgender Women
The Current Stands of Sport Organizations
Possible Solutions Proposed for Sports
Summary and Conclusions
References
18 Stress Reactivity and Exercise in Women
Introduction
Stress Reactivity and Health
Methods for Testing Stress Reactivity
Are There Sex Differences in Stress Reactivity?
Effects of Estrogen on Stress Reactivity
Menstrual Cycle Phases
Oral Contraceptives
Effects of Aging on Stress Reactivity in Women
Effects of Exercise on Stress Reactivity in Women
Acute Exercise
Regular Exercise
Conclusions and Future Directions
References
19 Exercise, Depression–Anxiety Disorders, and Sex Hormones
Introduction
Women’s Reproductive-Related Mood Disorders
Menstrually Related Mood Disorders (MRMDs)
Perinatal Depression
Depression During the Menopause Transition (Perimenopausal Depression)
Physical Activity and Women’s Reproductive-Related Mood Disorders
Relationships BetweenPhysical Activity and Menstrually Related Mood Disorders
Relationships Between Physical Activity and Perinatal Depression
Relationships Between Physical Activity and Affective Disorders During the Menopause Transition
Summary
References
20 Sex Hormones and Physical Activity in Women: An Evolutionary Framework
Introduction
Life History Theory: An Evolutionary Framework for Understanding Sex Hormones and Exercise in Women
Reproductive Ecology, Sex Hormones, and Exercise in Women
The Increasingly Important Focus on Obesity in Sex Hormones and Exercise
Conclusions
References
21 The Effects of Acute Exercise on Physiological Sexual Arousal in Women
Introduction
Physiological Sexual Arousal in Women
Effect of Acute Exercise on Physiological Sexual Response
Mechanism of Action for the Facilitation of Physiological Sexual Arousal with Exercise
Clinical Implication
Exercise and Sexual Arousal in Women with a History of Childhood Sexual Abuse
Exercise and Sexual Arousal in Women Who Have Undergone Hysterectomy
Exercise and Sexual Arousal in Women Who Are Cancer Survivors
Exercise and Sexual Arousal in Women Experiencing Antidepressant-Induced Sexual Dysfunction
Exercise and Sexual Arousal in Women with Multiple Sclerosis
Summary and Conclusions
References
22 Sex Hormones, Cancer, and Exercise Training in Women
Introduction
Epidemiology of Physical Activity and Sex Hormone-Related Cancer Risk
Proposed Mechanisms for Sex Hormone-Related Cancer Risk Reduction Due to Exercise
Exercise Effect: Pre-puberty
Exercise Effect: Puberty to Menopause
Effect of Exercise: After Menopause
Exercise Effect: High-Risk Groups
Future Directions
Summary
References
23 The Future of Sport and Exercise Science Research in the Female Athlete
Introduction
State of the Science
Methodology Considerations
Advances in Best Practices
Obstacles: Funding, Time, Recruitment, Validity
Future Work
Designing the Research Agenda
Areas for Future Work
Conclusion
References
24 Epilogue: “How We Arrived at This Point in Time”
Introduction
Historical Perspective and Comments
Personal Journey: A Few Reflections and Comments as an Athlete and Physician to Athletes
The Future and Questions Remaining
References
Index