Physiology Commons^™

The Effects Of Resistance Exercise Training On Insulin Resistance Development In Female Rodents With Type 1 Diabetes, Mitchell James Sammut

Electronic Thesis and Dissertation Repository

The etiology of insulin resistance (IR) development in type 1 diabetes mellitus (T1DM) remains unclear; however, impaired skeletal muscle metabolism may play a role. While IR development has been established in male T1DM rodents, female rodents have yet to be examined in this context. Resistance exercise training (RT) has been shown to improve IR and is associated with a lower risk of hypoglycemia onset in T1DM compared to aerobic exercise. Additionally, the molecular mechanisms mediating RT-induced improvements in insulin sensitivity remain unclear. Therefore, the purpose of this study was to investigate the effects of RT on IR development in female …

The Sympathetic Neural Control Of The Circulation At Rest And During Exercise: Effects Of Age, Biological Sex, And Sex Hormones, Andrew W. D'Souza

Electronic Thesis and Dissertation Repository

The overall objective of this dissertation was to determine the impact of age, sex, and sex hormones on the discharge behaviours of muscle sympathetic action potentials (APs) as well as the corresponding changes in peripheral vasoconstriction and blood pressure at rest and during exercise. The microneurographic technique was employed to record multi-unit muscle sympathetic nerve activity (MSNA), with a continuous wavelet transform applied post-hoc to evaluate APs within the recorded neurogram. Study One examined the impact of aging on the central and peripheral arcs of the sympathetic baroreflex under resting conditions. This study revealed that middle-aged-to-older adults demonstrated heightened sympathetic …

Does Acute Maximal Exercise Or Chronic Physical Activity Affect Circulating Angiotensin (1-9) Concentrations?, Kyle R. Weiman

Electronic Thesis and Dissertation Repository

Introduction: Epidemiological evidence suggests physical inactivity can increase the likelihood of hospitalization from the SARS-COV-2 virus. Further, some data indicate a greater ratio of angiotensin 1-9 to angiotensin I helps prevent severe outcomes during infection. Moreover, related hormones can enhance potentially both physical activity and health. The purpose of this study was to determine whether plasma concentrations of angiotensin (1-9) are modified after a single exhaustive exercise bout and whether sex or chronic physical activity is associated with greater plasma concentrations.

Methods: Participants (n=14) performed a graded exercise test on a cycle ergometer. Antecubital area venipunctures were performed before, immediately …

The Effect Of Breathing Patterns Common To Competitive Swimming On Gas Exchange And Muscle Deoxygenation During Heavy-Intensity Fartlek Exercise, Kevin J. Grossman

Electronic Thesis and Dissertation Repository

The purpose of this study was to compare the respiratory and muscle deoxygenation (HHb) responses of regulated breathing versus free-breathing, during continuous exercise (CONLD) and intermittent 5s breath holds (BH) (CONLD-BH), intermittent 5s sprint (FLK) and combined 5s BH and sprint (FLK-BH) followed by 25s of free-breathing. Oxygen uptake(V̇O₂)was unchanged between CONLD (2.12±0.35L/min) and CONLD-BH (2.15±0.42L/min; p=0.116), and FLK (2.24±0.40L/min) and FLK-BH (2.20±0.45L/min; p=0.861). Δ[Hb_tot]: CONLD (3.3±1.6µM) > CONLD-BH (-2.5±1.2µM; ∆177%; p<0.001), but unchanged between FLK (2.0±1.6µM) and FLK-BH (0.82±1.4µM; p=0.979). Δ[HHb]: CONLD (7.3±1.8µM) > CONLD-BH (7.0±2.0µM; ∆4%; p=0.011), and FLK (6.7±1.8µM) < FLK-BH (8.7±2.4µM; p<0.001). It is suggested that the unchanged V̇O₂ between CONLD and CONLD-BH was supported by increased deoxygenation, reflected by decreased ∆[Hb_tot] and blunted …

The Effect Of Sprint Interval Training And Intermittent Fasting On Cognitive Function, Dana Taghaddos

Undergraduate Student Research Internships Conference

This study will explore how a combination of a time-restricted eating (TRE) strategy and a sprint interval training (SIT) exercise program will affect cognitive function. Both TRE and SIT are easily implemented lifestyle habits that have been shown to present significant brain challenges. Participants will be randomized into 3 groups: either SIT + TRE (Group 1), SIT alone (Group 2), or TRE alone (Group 3). We will assess acute effects (single day of TRE, followed by a single session of SIT the next day), and the effects over a 6 week period. The SIT protocol consists of four 30 second …

Examining The Feasibility Of Delivering A Multi-Component Virtual Lifestyle Medicine Program For Adults With Type 2 Diabetes, Madison S. Hiemstra

Electronic Thesis and Dissertation Repository

BACKGROUND: The virtual delivery of lifestyle medicine programs (e.g., via web-conferencing platforms) can increase program accessibility for adults living with type 2 diabetes (T2D). PURPOSE: To assess the feasibility of virtually delivering a multi-component group-based lifestyle medicine program that uses wearable technologies and exercise prescriptions in an adult population with T2D. METHODS: This was a six-week, single-cohort feasibility study. The virtual lifestyle medicine program included live-video delivery of group education classes, one-on-one exercise counselling phone calls, flash glucose monitors, wearable activity monitors, and exercise prescriptions. Several feasibility outcomes were assessed including recruitment and retention rates, acceptability (e.g., exit survey), and …

Sexual Dimorphism In Response To Repetitive Bouts Of Acute Exercise In Rodents With Type 1 Diabetes Mellitus, Jordan C. Larocque

Electronic Thesis and Dissertation Repository

The purpose of this study was to examine sex-specific differences in the blood glucose (BG) response to recurrent aerobic exercise in type 1 diabetes. Specifically, we examined the role of peak estrogen (E2) concentrations during proestrus on BG response to prolonged aerobic exercise. To do so, nineteen Sprague-Dawley rats were assigned to four exercised groups: control female (CXF; n = 5), control male (CXM; n = 5), diabetic female (DXF, n = 5) and diabetic male (DXM, n = 4). Diabetes was induced in DX groups via subcutaneous injection of low dose streptozotocin. After four days of exercise, liver glycogen …

Understanding The Effects Of Physical Activity On Executive Functioning And Psycho-Emotional Well-Being In Children With Adhd, Hannah B. Bigelow

Electronic Thesis and Dissertation Repository

A short bout of physical activity has been shown to improve executive functioning in children. However, the implications for children with Attention Deficit Hyperactivity Disorder (ADHD) has been understudied. We examined the impact of a 10min bout of physical activity on executive functioning and psycho-emotional well-being in children with ADHD. Participants engaged in two lab-based sessions separated by 1-week: a physical activity session and a control session. The physical activity session included a 10min bout of moderate-intensity biking, with a pre-post battery of cognitive and psycho-emotional assessments. The control session consisted of 10mins of silent reading. We used functional imaging …

A Four Week 30 S Weight Training Intervention Improves 2000 M Rowing Ergometer Performance Of Provincial And National Collegiate Female Rowers, Matthew Lee

Electronic Thesis and Dissertation Repository

This study compared the effects of a 4 week, 30 s weight training program (30SEC), to a low-repetition weight training program (LoRep), on rowing performance and aerobic capacity in preconditioned, provincial and national collegiate female rowers. 30SEC (n=5) performed 5 sets of dumbbell deadlifts (DL) and dumbbell bench pulls (BP), executing a maximum of 18 repetitions in 30 s, three times per week. LoRep (n=5) performed 4-5 sets of 2-6 repetitions of weight training exercises twice per week. Both regimes performed an identical high volume of predominantly aerobic rowing ergometer training. 30SEC improved 1 Minute Test (p2max, peak power output …

Menstrual Phase Differences In Muscle Deoxygenation, Respiration And Blood Lactate Concentration Do Not Influence Exercise Performance, Jordyn L. Smith

Electronic Thesis and Dissertation Repository

The purpose was to evaluate muscle deoxygenation (Δ[HHb]), oxygen uptake (VO2), ventilation (VE), and arterialized blood lactate [La-] throughout exhaustive incremental (RAMP) and severe-intensity exercise (SI) during follicular (FOL) and luteal (LUT) menstrual phases. During RAMP, Δ[HHb]/VO2 was 65% lower in LUT below gas exchange threshold (p0.05). During SI,Δ[HHb]/VO2 was 18% lower in LUT during the kinetic phase (p0.05). No FOL/LUT differences in RAMP-performance (FOL: 218 ± 35 W; LUT: 221 ± 29 W) or SI-endurance (FOL: 99 ± 20 s; LUT: 96 ± 15 s) (p>0.05) were found. These data demonstrate that physiological differences between menstrual phases exist, …

Pilot Study: Heart Rate Variability Analysis And Mental Health Outcomes In University Female Hockey Players, Kaitlyn Jacobs

Electronic Thesis and Dissertation Repository

Exercise improves anxiety and depression, both of which are associated with impaired autonomic regulation of heart rate (HR). In turn, HR variability (HRV) is a reliable physiological indicator of external stressors. The following research tested the hypothesis that HRV is indicative of chronic resilience towards mental stress in female varsity hockey players. Seventeen varsity hockey players (HOCK, age 21 ± 1.5) and fifteen healthy controls (CTRL, age 21 ± 2.2) at Western University participated three times throughout a 7-month season. Participants completed questionnaires (brief resilience scale, BRS; generalized anxiety scale, GAD-7; mental health inventory, MHI; visual analog scale, VAS; short …

Power Reserve Following Ramp-Incremental Cycling To Exhaustion: Implications For Muscle Fatigue And Function, Michael D. Hodgson

Electronic Thesis and Dissertation Repository

In ramp-incremental cycling exercise, some individuals are capable of producing power output (PO) in excess of that produced at their limit of tolerance (LoT) while others cannot. This study sought to describe the: 1) prevalence of a “power reserve” within a group of young men (n=21; mean ± SD: age 25±4 years; V̇O_2max45±8 ml•kg^-1•min^-1); and 2) muscle fatigue characteristics of those with and without a power reserve. Power reserve was determined as the difference between peak PO achieved during a ramp-incremental test to exhaustion and maximal, single-leg isokinetic dynamometer power. Pre- versus post-exercise changes …

The Effects Of Moderate Intensity Strength Training Coupled With Blood Flow Restriction: A 12 Week Intervention, Kelly Barrett

Electronic Thesis and Dissertation Repository

Blood flow restriction training (BFRT) has been suggested to increase muscle size and strength in trained and untrained individuals when using light load intensities (30 percent 1-RM). However, there is little data to support its use when working with moderate load intensities, specifically, above 50 percent of an individual’s 1-RM. The purpose of this study was to evaluate the effects of moderate load intensity BFRT on muscle size and strength of the biceps brachii after a 12 week strength training intervention. Nine, previously strength trained, participants performed an elbow flexion exercise at 70 percent of their individualized 1-RM, twice per …

Physiological Resolution Of Periodic Breath Holding During Heavy Intensity Fartlek Exercise, David J. Lim

Electronic Thesis and Dissertation Repository

The purpose was to compare the physiological responses to periodic 5 s breath holds (CBH), increased power output (FLK), and both (FBH) every 30 s followed by 25 s of continuous heavy intensity cycling exercise with free-breathing (CON). Minute ventilation (V̇ E) was greater (p < 0.05) in CBH (97.58 + 16 L·min-1) and FBH (100.9 + 19 L·min-1), pulmonary oxygen uptake (V̇ O2p) was similar in CBH (2.73 + 0.14 L·min-1) and FBH (2.73 + 0.14 L·min-1) and greater in FLK (2.85 + 0.12 L·min-1), compared to CON (2.71 + 0.12 L·min-1). FBH also resulted in slower V̇ O2p kinetics (62.2 + 19 s) and greater blood lactate concentrations (11.5 + 2.7 mM), compared to CON (48.8 + 12 s; 9.0 + 2.3 mM). Together, we demonstrated that breath hold-induced hypoxemia and hypercapnia were resolved when not combined with additional work.

The Effect Of Insulin Treatment And Exercise Modality On Skeletal Muscle Fiber Size In Streptozotocin-Induced Type 1 Diabetic Rats, John Z. Nickels

Electronic Thesis and Dissertation Repository

Severe Type 1 Diabetes Mellitus (T1DM) is known to have several negative effects on skeletal muscle mass, a condition known as diabetic myopathy. One of these effects is the atrophy of the glycolytic muscle fibers. However, the role of intensity of insulin treatment and exercise modality in attenuating this loss in fiber cross-sectional area (CSA) specifically has yet to be determined. The purpose of this investigation was to determine the effects of 12 weeks of differing intensity of insulin therapy and exercise modality on the CSA of plantaris muscle fibers, identified by myosin heavy chain (MHC) of STZ-induced T1DM rats. …

The Long Haul: Migratory Flight Preparation And Performance In Songbirds, Morag F. Dick

Electronic Thesis and Dissertation Repository

Migration requires birds to sustain high intensity endurance exercise for periods lasting from hours to days. Similar to athletes, preparation and nutrition is key to success. Birds seasonally prepare for migration, which includes increasing the capacity to oxidize fat in the flight muscles. Beyond fuelling migration, n-3 long-chain polyunsaturated fatty acids (PUFA) are hypothesized to be natural doping agents and increase endurance and fatty acid oxidative capacity. I examined how birds prepare for and sustain migratory flight and directly tested the role of n-3 PUFA. Using yellow-rumped warblers (Setophaga coronata) as a model species, I first examined the …

The Neuroprotective Effects Of Endurance Training On The Aging Brain, Katelyn Norton

Electronic Thesis and Dissertation Repository

Dysregulation of autonomic control often develops with advancing age, favoring a chronic state of heightened sympathetic outflow with parasympathetic withdrawal. However, the mechanisms of this age-related autonomic impairment are not known and may relate to alterations in brain structure (e.g. cortical atrophy) and/or altered neural function, particularly in regions related to the cortical autonomic network, namely, the medial prefrontal cortex (MPFC), insula cortex (IC), and hippocampus (HC). Exercise exerts beneficial effects on brain structure and, in the case of cognition, neurologic function; however, how exercise affects regions of the brain related to autonomic function are not known. This thesis tested …

The Cardiovascular Benefits Of Regular Exercise In Type 1 Diabetes Mellitus And The Risk Of Exercise-Induced Hypoglycemia, Matthew W. Mcdonald

Electronic Thesis and Dissertation Repository

Type 1 diabetes mellitus (T1DM) is associated with compromised glycemic control and a heightened risk for cardiovascular disease. The common treatment of T1DM with strict glycemic control through intensive insulin therapy can be problematic (weight gain, insulin resistance, hypoglycemia). Regular exercise is known to improve cardiovascular health, yet most individuals with T1DM remain sedentary, and identify the risk of exercise-induced hypoglycemia as a significant barrier. The investigation into the use of different forms of exercise (higher intensity, resistance) for preventing exercise-induced hypoglycemia in populations with T1DM has been promising, however, little work has investigated their cardiovascular benefit or whether the …

Degrees Of Damage: Quantifying Male Vs. Female Exercise-Induced Muscle Damage Through Magnetization Transfer Ratios, Nicholai Michael Clausius Crawford

Electronic Thesis and Dissertation Repository

No direct, quantitative, and non-invasive markers presently exist to assess exercise-induced muscle damage (EIMD). However, magnetization transfer ratios (MTR), an emerging measurement quantified via magnetic resonance imagery, provide more direct indication of muscle integrity following EIMD. This study compares and correlates the temporal pattern of the MTR to alternative indirect markers of EIMD in male vs. female populations, and subsequently establishes whether there are sex differences in biochemical activity during recovery. The antioxidant properties of estrogen hypothetically minimize muscle trauma, maintain membrane stability, and limit swelling resulting in heightened tissue integrity and resilience to EIMD. Six males and three females …

Examination Of The Non-Linear V̇O2p Response To Exercise: Non-Invasive Evidence Of Linear Systems Control Using V̇O2p Kinetic Analyses, Daniel A. Keir

Electronic Thesis and Dissertation Repository

The pulmonary O₂ uptake (V̇O_2p) response to exercise has been characterized by exponential kinetics that remain constant regardless of the exercise protocol used to force the change in V̇O_2p (kinetics are invariant). A system that responds in this way is classified as “dynamically linear”, implying that a first-order rate reaction controls V̇O₂ at the muscle level (V̇O_2m). However, slowed V̇O_2p kinetics when initiating exercise from raised baseline intensities challenges this notion. The purpose of this thesis was to characterize the rate (τV̇O_2p) and magnitude (gain) of adjustment of V̇O_{2p …}

The Effect Of A Multiple Modality Mind-Motor Exercise Intervention On Single And Dual-Task Gait, Balance, And Executive Function, In Community Dwelling Older Adults With A Subjective Cognitive Complaint: A Randomized Controlled Trial., John P. Bocti

Electronic Thesis and Dissertation Repository

Cognitive decline disorders are becoming increasingly prevalent, with older adults at increased risk. Combined exercise has been recently explored as an intervention to help to prevent the decline, however cognitive activation in combination with physical activity has yet to be explored. Therefore, the purpose of the study is to determine the effects of multiple modality exercise programs in combination with a mind-motor task and their effects on mobility and cognitive variables. A total of (n=89) older adults (55+ yrs), with subjective cognitive complaints participated in a multiple modality exercise class, three days a week over six months, with the intervention …

Biosteel High Performance Sports Drink Improves Exercise Performance Following A Simulated Hockey Game, Kolten C. Abbott

Electronic Thesis and Dissertation Repository

INTRODUCTION: BioSteel High Performance Sports Drink (BioSteel) is one of the most popular sports supplements consumed by professional and amateur athletes. BioSteel Inc^® claims that consumption of BioSteel before and during exercise will result in “enhanced energy while delaying the onset of muscular and mental fatigue”. PURPOSE: Assess the efficacy of BioSteel supplementation on anaerobic and aerobic exercise performance as well as sport-specific cognition throughout exercise. METHODS: Eleven exercise-trained men completed a simulated hockey game on a cycle ergometer under two experimental conditions: BioSteel and isoenergetic placebo. Measures of exercise performance and cognition were assessed before, throughout and after …

Quantifying The Effect Of Age And Contraction Mode On The Force-Velocity-Power Relationship In The Knee Extensors, Justin R. Paturel

Electronic Thesis and Dissertation Repository

PURPOSE: To assess and compare the force-velocity-power relationship (F-V-P) using isotonic and isokinetic knee extensions in 11 younger (19-30y) and 11 older (69-81y) men. METHODS: The construction of the F-V-P curves were attained with each participant performing maximal, explosive knee extensions at 8 different loads (isotonic) and 8 different velocities (isokinetic) on a Cybex HUMAC NORM dynamometer. Maximal voluntary contraction (MVC or P_o), maximal shortening velocity (V_max), maximum power, optimal torque (P_opt) and velocity (V_opt) were assessed and compared. RESULTS: The older men were 43% weaker, 18% slower and ~54% less powerful …

Functional Anatomy Of The Anconeus: Muscle Architecture And Motor Unit Number Estimation, Daniel E. Stevens

Electronic Thesis and Dissertation Repository

Exploring muscle architecture in vivo and estimating the number of MUs in the human anconeus muscle have important implications related to the neuromuscular function of this muscle as a model for study in health and disease. The two studies presented in this thesis investigate the functional anatomy of the anconeus in 10 healthy young men (25±3y).

Ultrasound imaging has facilitated the measure of the architectural variables, fascicle length (L_F) and pennation angle (PA), in many human skeletal muscles in vivo. However, the functional anatomy of the anconeus has been investigated mainly from cadavers exclusively. Thus, the purpose …

The Effect Of Testosterone On The Spring Migratory Phenotype Of A North American Songbird (Zonotrichia Albicollis), Caitlin L. Vandermeer

Electronic Thesis and Dissertation Repository

In passerines, the endocrine modulators responsible for seasonal changes in migratory behaviour and physiology are unclear. Spring photoperiods alter androgen levels, influencing muscle mass and fat deposition rates to power migration, as well as enhance nocturnal migratory restlessness activity (Zugunruhe). My study compared physiological indicators and migratory restlessness in castrated and intact white-throated sparrows (Zonotrichia albicollis) following photoperiod and hormone manipulation. Nocturnal restlessness activity was highest in migratory intact males or migratory castrated males that received testosterone replacement. Liver mass decreased in all photostimulated migratory groups regardless of testosterone treatment. Likewise, oxidative enzyme activity was unrelated to testosterone, …

Role Of Adenylyl Cyclase S674 In Central And Forearm Vasomotor Control, James Corkal

Electronic Thesis and Dissertation Repository

This study examined the cardiac and vasomotor responses to submaximal handgrip exercise and beta-adrenergic control in carriers (n = 6) and non-carriers (n = 4) of a genetic variant of adenylyl cyclase 6 (AC S674). Rhythmic handgrip contractions (1 minute bout; 2 second contraction-relaxation period) were performed at three different intensities (20, 40, and 60% of maximal voluntary contraction force) to test the vasodilatory response to exercise. Additionally, two 5 minute infusions of isoproterenol (0.01 and 0.02 µg·kg^-1·min^-1 diluted in 5% dextrose) and one 10 minute infusion of propranolol (0.1 mg·kg^-1 diluted in 0.9% saline) were …

The Effect Of Aerobic Exercise Training On Cerebrovascular Hsp70, Hsp90, Inos And Enos Expression In Type 1 Diabetes, Adwitia Dey

Electronic Thesis and Dissertation Repository

The purpose of this study was to determine the effect of exercise training alone and in a model of Type 1 Diabetes Mellitus (T1DM), on Heat Shock Protein (HSP) and Nitric Oxide Synthase (NOS) expression in entorhinal adjacent large and small cerebral vessels. Thirty-two rats were randomly allocated to four groups: control sedentary (C), control exercised (CX), diabetic sedentary (D) and diabetic exercised (DX). Exercise training incorporated 5 days/week on a motorized treadmill (27m/min; 6 degree incline; 1 hour) for 10 weeks. Exercise trained groups had significantly greater Hsp70 expression than their respective non-trained groups (p<0.05) and this response was not blunted in T1DM animals. The inducible NOS (iNOS) expression was greater in diabetic sedentary when compared to all other groups (p<0.001). Co-localization of protein with smooth muscle cells illustrates that all HSP and NOS signal content is localized to the smooth muscle area (SMA).

The Cost Of Ethanol Synthesis During Recovery From Exhaustive Exercise In Grass Carp (Ctenopharyngodon Idella), Simon A. Bradford

Electronic Thesis and Dissertation Repository

Grass carp (Ctenopharyngodon idella) reduce white muscle glycogen (~14 µmol glucosyl units/g wet tissue) in response to exhaustive exercise. This reduction results in a small increase in muscle lactate (~9 µmol/g wet tissue) and a larger increase in muscle ethanol (~30 µmol/g wet tissue). Tissue-specific and whole-body measures of glycogen, ethanol and lactate confirm that ethanol is the major “anaerobic” glycolytic end-product. Additionally, while peak muscle and blood ethanol levels occur immediately post-exercise, the excretion of ethanol to the environment is delayed, occurring over a 30-minute period beginning ~105 minutes following exercise. As the total amount of ethanol …

Neuromuscular Function Following Lengthening Contractions, Geoffrey A. Power

Electronic Thesis and Dissertation Repository

Unaccustomed lengthening contractions have been shown to impair muscle function - however little is known regarding this impairment on muscle power - specifically, the velocity component of power during voluntary contractions in humans. The four studies presented in my thesis investigated power-loss following lengthening contractions in healthy young and old women and young men.

The purpose of Study 1 was to determine reliability of velocity-dependent power of the dorsiflexors using the isotonic mode of the Biodex Dynamometer. I determined the isotonic mode is reliable and can be used to track changes in velocity and power following fatigue and lengthening contractions. …

Neuroprotective Effects Of Long-Term Endurance Training On The Cortical Autonomic Network In The Aging Brain, Torri A. Luchyshyn

Electronic Thesis and Dissertation Repository

This study tested whether long-term endurance training in older adults (ET; n = 15, 55 ± 4 years, relative VO₂max = 50 ± 8 ml/kg/min) would alter cardiovagal control and preserve the cortical autonomic network compared to age-matched controls (CON; n = 15, 56 ± 4 years, relative VO₂max = 37 ± 9 ml/kg/min). The hypothesis predicts 1) altered deactivation patterns of the ventral medial prefrontal cortex (vMPFC) in response to isometric hand grip (IHG) and 2) greater indices of cardiovagal control; a) increased baroreflex sensitivity at rest, b) greater heart rate change (ΔHR) and c) …