CHANGES IN BODY COMPOSITION AND CARDIOMETABOLIC HEALTH OBSERVED IN NORMAL-WEIGHT COLLEGE STUDENTS ACROSS EACH COLLEGE YEAR Austin Michael Peterjohn A thesis submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Exercise and Sport Science (Exercise Physiology). Chapel Hill 2019 Approved by: Abbie Smith-Ryan Kristin Ondrak Katie Hirsch © 2019 Austin Michael Peterjohn ALL RIGHTS RESERVED ii ABSTRACT Austin Peterjohn: Changes in Body Composition and Cardiometabolic Health Observed in Normal-Weight College Students Across Each College Year (Under the direction of Abbie Smith-Ryan) The present study described changes in body composition and cardiometabolic health during one academic year in male and female college students of each academic class (n=143). Students completed body composition and cardiometabolic health analyses during a single visit on three separate occasions: early Fall semester (August-October) 2017, late spring semester (March-May) 2018, and early Fall semester (August-October) 2018. There was a main effect for time for body mass (p=0.035), BMI (p=0.025), lean mass (p=0.007), and fasting glucose (p=0.046). Females saw significant gains in body mass (p=0.015), BMI (p=0.015), and lean mass (p=0.002). Lean mass of seniors significantly increased (p=0.010) from Fall 2017 to Spring 2018, but no other differences between classes were found with respect to body composition and cardiometabolic health. The results of this study suggest minimal changes in body composition and cardiometabolic health occur during one year of college, regardless of class. iii ACKNOWLEDGEMENTS I would like to thank my committee for their contribution to this project and their guidance throughout this experience. The quality of this project stems from the contributions and advice my committee gave to me, and I can’t thank them enough. My lab team deserves a huge “thank you,” for their effort in this project. Not only were they helpful and supportive, but I also had a blast working with such amazing individuals, and I value their friendship greatly. I also have my friends and family to thank for their support over the course of this project and my time studying at UNC. It was a marathon I may not have finished without their continued support and encouragement. Lastly, I’d like to thank my advisor, Dr. Smith-Ryan, for her continued encouragement and belief in me as a student and researcher. She was always in my corner and pushed me to succeed when I needed it most. iv TABLE OF CONTENTS LIST OF TABLES .............................................................................................................. vii LIST OF FIGURES ............................................................................................................ viii LIST OF ABBREVIATIONS ............................................................................................... ix CHAPTER I: INTRODUCTION ........................................................................................... 1 Purpose .........................................................................................................................................3 Research Questions: .....................................................................................................................4 Research Hypotheses: ...................................................................................................................5 Limitations: ..................................................................................................................................5 Delimitations: ...............................................................................................................................6 Significance: .................................................................................................................................6 CHAPTER II: REVIEW OF LITERATURE ......................................................................... 7 Introduction ..................................................................................................................................7 Body Composition ..........................................................................................................................8 College Weight Gain .................................................................................................................... 11 Normal Weight Obesity ................................................................................................................ 13 Lifestyle Factors .......................................................................................................................... 15 Physical Activity ................................................................................................................................................. 16 Alcohol Consumption ......................................................................................................................................... 17 Dietary Habits .................................................................................................................................................... 17 Stress .................................................................................................................................................................. 18 Sleep ................................................................................................................................................................... 19 Questionnaires and Surveys ............................................................................................................................... 20 Conclusions ........................................................................................................................................................ 21 CHAPTER III: METHODS ................................................................................................ 23 Participants ................................................................................................................................. 23 Experimental Design ................................................................................................................... 24 Body Composition ........................................................................................................................ 24 Cardiometabolic Health ............................................................................................................... 25 v Questionnaires ............................................................................................................................ 25 Statistical analysis ........................................................................................................................ 26 CHAPTER IV: MANUSCRIPT ........................................................................................... 28 Introduction ................................................................................................................................ 28 Participants and Methods .................................................................................................................................. 30 Experimental Design ................................................................................................................... 31 Anthropometric and Body Composition Analysis .............................................................................................. 31 Cardiometabolic Health ..................................................................................................................................... 32 Lifestyle Questionnaires ..................................................................................................................................... 33 Statistical Analysis ............................................................................................................................................. 33 Results ........................................................................................................................................ 34 Anthropometrics ................................................................................................................................................. 34 Body Composition .............................................................................................................................................. 35 Cardiometabolic Health ..................................................................................................................................... 35 Males vs. Females .............................................................................................................................................. 36 Lifestyle Factors ................................................................................................................................................. 37 Discussion ................................................................................................................................... 38 Body Mass and BMI ........................................................................................................................................... 39 Body Composition .............................................................................................................................................. 40 Cardiometabolic Health ....................................................................................................................................