The effects of aerobic and resistance exercise training on the cardiometabolic health of ...

287 Pages·2013·21.76 MB·English

The effects of aerobic and resistance exercise training on the
cardiometabolic health of adolescents with obesity

Angela Stephanie Alberga, M.Sc.

Thesis submitted to the
Faculty of Graduate and Postdoctoral Studies
in partial fulfillment of the requirements
for the PhD degree in Human Kinetics- Exercise Physiology

School of Human Kinetics
Faculty of Health Sciences
University of Ottawa

© Angela Stephanie Alberga, Ottawa, Canada, 2013
ABSTRACT

Physical inactivity and obesity in adolescence are associated with an increased risk of
cardiovascular disease (CVD). Although exercise is recommended for the management of
obesity, we know little about which types of exercise training are the most effective in reducing
excess body fat and improving CVD risk in obese adolescents. This dissertation examined the
effects of aerobic training, resistance training and their combination on the cardiometabolic
health (body composition, CVD risk markers, resting metabolic rate (RMR), and fitness) of
obese adolescents who participated in the Healthy Eating Aerobic and Resistance Training in
Youth (HEARTY) trial. After a 4-week supervised moderate-intensity exercise run-in period,
304 overweight and obese adolescents were randomized to 4 groups for 22 weeks: Aerobic
training, Resistance training, Combined aerobic and resistance exercise training, or a non-
exercising Control. All four groups received dietary counseling designed to promote healthy
eating with a maximum daily energy deficit of 250 kcal. Participants were assessed at baseline
and after 3 and 6 months. Body composition was assessed using magnetic resonance imaging.
Blood tests for traditional and non-traditional CVD risk markers were measured after a 12-hour
fast. RMR and cardiorespiratory fitness were assessed using indirect calorimetry at rest and
during a maximal treadmill test respectively. Musculoskeletal fitness (muscular strength,
endurance, flexibility) was assessed using eight repetition maximum tests (8-RM) on the leg
press, chest press and upright row machines and using the Canadian Society for Exercise
Physiology- Canadian Physical Activity Fitness and Lifestyle Appraisal (CSEP-CPAFLA) tests
for grip strength, push-ups, sit-ups, sit and reach and vertical jump. Decreases in percent body fat
and abdominal fat were greatest in the combined training group. Although body weight, RMR
and traditional CVD risk markers did not improve following the exercise intervention, the
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combined training group showed improvements in cardiorespiratory and musculoskeletal fitness
and some non-traditional CVD risk markers. Cumulatively, combined aerobic and resistance
exercise training showed the greatest improvements in cardiometabolic health in overweight and
obese adolescents. This thesis concludes with a knowledge translation article detailing the
practical lessons learned from exercise interventions with obese youth with hopes of increasing
adherence to future exercise programs and improving the overall health of children and
adolescents with obesity.

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ACKNOWLEDGEMENTS

As I write this section, I am overwhelmed with emotion thinking of all the people who
uniquely contributed to this doctoral thesis and helped make this such a rewarding journey.
Throughout my undergraduate degree at Concordia University, Montreal, Dr. Joanna
Komorowski’s passionate teaching inspired me to pursue clinical research. Joanna, you quickly
became my mentor, great friend and colleague, and always provided me with inspiring wisdom
and advice in all realms of life. Thank you for always believing in me.
My aspirations to help children and youth with obesity led me to the University of
Ottawa where I had the privilege of working with my co-supervisors Drs. Glen Kenny and Denis
Prud’homme throughout both my MSc and PhD degrees. Glen, your dedication and passion for
research is enviable. You taught me to be meticulous and to strive for excellence through
perseverance and hard work. You always made time for impromptu meetings and long debates
and I am so grateful for all your support. Thank you. To the Human and Environmental
Physiology Research Unit lab mates, thank you for your ongoing advice, random office
conversations and friendly support over the years.
Denis, de par votre sagesse et votre enseignement remarquable, vous m’avez aidé à
mieux comprendre la recherche clinique, à mieux analyser et questionner les articles
scientifiques ainsi qu’à devenir une meilleure chercheure. Même en étant doyen, vous avez
toujours su avoir comme priorité vos étudiants et pour cela je vous en suis très reconnaissante. Je
vous remercie également de votre soutien et vos encouragements au cours des dernières années.
To Denis’ research team, I will greatly miss our weekly journal club meetings, engaging
scientific discussions, and conference travels.
I must thank Dr. Ron Sigal, who played a pivotal role in developing my skills as a
researcher. Ron, you taught me the true essence of critical thinking. Your attention to detail and
thinking ‘outside the box’ greatly developed my research and writing skills. Despite the long
distance, you prioritized communication with me via email and teleconferences and always
provided me with insightful feedback. I have learned so much from you. Thank you.
I want to express my sincerest thanks to Dr. Kristi Adamo who has been a wonderful role
model throughout this process. Kristi, your expertise in pediatrics (both at work as an
accomplished scientist and at home as a loving mother) is remarkable. It has been such a
pleasure chatting with you, working with you on my practical paper, and being your Master
Trainer for your preschool physical activity trial. You provided invaluable insight and advice
throughout this degree and I hope this is only the beginning of many future collaborations.
I am forever indebted to the HEARTY research team and all of our participants. Having
been involved in all facets of the HEARTY clinical trial from patient recruitment, screening,
personal training, and testing, I had the opportunity to interact with 350+ teenagers who
graciously committed their time to participate in this study. I was fortunate to work with the best
multidisciplinary team of obesity experts, endocrinologists, clinical psychologists, dieticians, and
exercise specialists, and have learned a great deal from each and every one of you. Special
thanks to Drs. Stasia Hadjiyannakis and Gary Goldfield for their encouragement, collaboration
and friendly support over the years. I am especially grateful for our wonderful research
coordinator, Ms. Penny Phillips, for her efficient communication, dedication and consistent help
throughout the years. I had so much fun working with all of you.
I would like to extend a big thanks to Dr. Bob Ross’ lab for hosting Dr. Jane Yardley and
I at Queen’s University and teaching us MRI and CT body composition analysis. A special
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thanks to Dr. Jennifer Kuk, Ms. Alison Bradshaw, Yves Martel for the analysis training sessions,
the ongoing support, advice, and communication throughout the years. Thank you to our MRI
technicians at CHEO and MRI+ and my fellow ‘slice-o team’ who helped me tremendously
throughout the analysis process.
I must also thank Dr. George Wells, Jinhui Ma, and Steve Doucette for their exceptional
statistical expertise. Special thanks to Steve Doucette for his dedication, remarkable teaching
skills and his uncanny ability to explain statistical concepts with ease and enthusiasm.
Thank you to the Canadian Institutes of Health Research for funding the HEARTY trial
and the Canadian Diabetes Association for my Doctoral Research Award. I must gratefully
acknowledge the Faculty of Health Sciences, the Faculty of Graduate and Postdoctoral Studies,
the Graduate Student Association and the Canadian Union of Public Employees at the University
of Ottawa, the Ottawa Hospital Research Institute and my supervisors for the financial support,
teaching, and research assistantships, and giving me the opportunity to present my research at
national and international conferences.
Being a volunteer for Let’s Talk Science, Science Travels and the Canadian Institutes of
Health Research-Synapse programs allowed me to bridge the gap between research and youth
education with hopes of inspiring young generations to become future scientists. Thank you for
constantly reminding me why I love science and the invaluable teaching and community
outreach experiences I had in local classrooms and in northern remote communities that truly
shaped me into who I am today. I must also sincerely thank the Canadian Obesity Network for
all the professional development and networking opportunities created for students and new
professionals to organize conferences, participate in knowledge translation events, and make
long-lasting friendships along the way.
To my fellow trainees and friends in the School of Human Kinetics at Montpetit Hall,
Lees, and CHEO, thank you for the conversations, memorable conference travels, ongoing
support, great laughs and everlasting friendship throughout the years. Graduate studies would not
have been the same without you. To the faculty and staff at the University of Ottawa, I will
greatly miss our random conversations in the offices, hallways and staircases but I look forward
to collaborating with many of you in the future. Lise O’Reilly, you helped me so much along the
way, I wish you could have been there on the 2nd floor of MNT Hall when I handed in my
doctoral thesis. Un gros merci à Marie Fortier, Marie-France Chayer, Isabelle Laforest, Bettyna
Bélizaire, Anne Millette et Catherine Cusson-Garneau pour vos sourires et votre aide constante
au cours des dernières années. Sans vous, j’aurais été complètement perdue!
To Rae, the girls, and all my closest friends in Montreal, Ottawa, and Vancouver, your
friendship knows no boundaries and I thank you for always being there for me and making me
laugh even in some of the most stressful times. You are THE BEST support network and I am so
grateful to have you all in my life.
I conclude my acknowledgements with my utmost and deepest gratitude to my family. I
am eternally thankful for my dad, mom and sister Steph for being there for me every step of the
way. Dad, you taught me the true meanings of the words ambition, diligence, perseverance and
hard work. Mom, you taught me how to teach, how to keep a smile on my face, and how
important it is to maintain a good sense of humour even when the going gets tough. Stephie, you
are the world’s best sister, my comic relief, and my younger sibling who demonstrates wisdom
beyond her years. I love you all and am so grateful to have such a loving, supportive and
generous family. I dedicate this thesis to you… so now you can really see what I have been
doing in Ottawa for the past few years!
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TABLE OF CONTENTS

ABSTRACT ................................................................................................................................... ii
ACKNOWLEDGEMENTS ........................................................................................................ iv
LIST OF ABBREVIATIONS ................................................................................................... viii
CHAPTER I: INTRODUCTION ................................................................................................ 1
General introduction .................................................................................................................... 2
Objectives .................................................................................................................................... 4
Hypotheses .................................................................................................................................. 4
Structure of the thesis .................................................................................................................. 5
CHAPTER II: LITERATURE REVIEW .................................................................................. 6
MANUSCRIPT 1: Overweight and Obese Teenagers: Why is Adolescence a Critical Period? 7
MANUSCRIPT 2: A Review of Aerobic Exercise Training in Obese Adolescents ................ 21
MANUSCRIPT 3: A Review of Resistance Exercise Training in Obese Adolescents ............ 36
CHAPTER III: METHODS ...................................................................................................... 51
MANUSCRIPT 4: Healthy Eating, Aerobic and Resistance Training in Youth (HEARTY):
Study Rationale, Design and Methods ...................................................................................... 52
CHAPTER IV: RESULTS ......................................................................................................... 62
MANUSCRIPT 5: Effects of aerobic training, resistance training, or both on percent body fat
and cardiometabolic risk markers in obese adolescents: the HEARTY trial ............................ 64
MANUSCRIPT 6: Effects of aerobic training, resistance training or both on abdominal fat
distribution, apolipoproteins and high-sensitivity C-reactive protein in obese adolescents: the
HEARTY trial ......................................................................................................................... 116
MANUSCRIPT 7: Exercise training and resting metabolic rate in obese adolescents: the
HEARTY trial ......................................................................................................................... 147
MANUSCRIPT 8: Effects of aerobic training, resistance training or both on cardiorespiratory
and musculoskeletal fitness in obese adolescents: the HEARTY trial.................................... 185
CHAPTER V: FINAL DISCUSSION ..................................................................................... 217
Final discussion ....................................................................................................................... 218
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MANUSCRIPT 9: Top 10 practical lessons learned from physical activity interventions in
overweight and obese children and adolescents ...................................................................... 227
Conclusion ............................................................................................................................... 238
REFERENCES .......................................................................................................................... 239
APPENDIX ................................................................................................................................ 245
Ethical Approvals .................................................................................................................... 246
Consent Form & Information Sheet ........................................................................................ 249
Magnetic Resonance Imaging (MRI) Analysis ....................................................................... 255
Data Collection Sheets ............................................................................................................ 260
Knowledge Translation Invitation ........................................................................................... 264
Journal Reprint Permissions .................................................................................................... 268

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LIST OF ABBREVIATIONS

Aerobic Aerobic exercise training group
ApoA-1 Apolipoprotein A-1
ApoB Apolipoprotein B
BMI Body mass index
Combined Combined aerobic and resistance exercise training group
CPAFLA Canadian Physical Activity Fitness and Lifestyle Appraisal
CRF Cardiorespiratory fitness
CSEP Canadian Society for Exercise Physiology
CVD Cardiovascular disease
deepSAT Deep layer of abdominal subcutaneous adipose tissue
HbA1c Hemoglobin A1c
HDL High-density lipoprotein cholesterol
HEARTY Healthy Eating Aerobic and Resistance Training in Youth
HSCRP High-sensitivity C-reactive protein
kcal kilocalories
LDL Low-density lipoprotein cholesterol
ITT Intention-to-treat analysis (includes entire sample, even dropouts)
MRI Magnetic resonance imaging
PA Physical activity
PP Per-protocol analysis (includes only participants with ≥70% adherence)
Resistance Resistance exercise training group
RMR Resting metabolic rate
RM Repetition maximum
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SAT Subcutaneous adipose tissue or subcutaneous fat
Superficial SAT Superficial layer of abdominal subcutaneous adipose tissue
VAT Visceral adipose tissue or visceral fat
VO Peak oxygen consumption
2peak
%BF Percent body fat

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CHAPTER I: INTRODUCTION

1