Award Date

August 2023

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Interdisciplinary Programs

First Committee Member

Graham McGinnis

Second Committee Member

James Navalta

Third Committee Member

John Mercer

Fourth Committee Member

Dustin Hines

Number of Pages



Circadian rhythms lie within every tissue and cell and regulate cellular and tissue processes and functions based upon the time of day. Disrupting the circadian clock results in impaired tissue and organ activity and higher risk of cardiometabolic diseases. A common form of circadian rhythm disruption is social jetlag (SJL), which represents the misalignment of sleep and wake times on free days and work days (i.e. weekend). The time of day of exercise affects the adaptations that are derived from exercise. Within the heart muscle, disparate levels of exercise-induced hypertrophy, circadian clock gene expression, and mitochondrial content were all dependent upon when exercise was performed, all without disrupting the light:dark cycle. Exercise is a potent therapeutic that improves obesity, glucose tolerance, and cardiometabolic health. When circadian rhythms were disrupted with SJL exercise caused faster resynchronization back to weekday activity. However, SJL also caused fasting blood glucose and overall glucose tolerance were impaired in both sedentary and exercising mice. While exercise prevented SJL-induced weight gain, SJL hampered exercise performance and inhibited exercise-induced mitochondrial adaptations in both the heart and skeletal muscle. The findings of this dissertation suggest that adaptation to exercise is affected by the status of the circadian rhythm, and that disrupting light:dark cycles or normal activity rhythms results in impaired adaptations in the heart and skeletal muscle.


Exercise physiology; sport science



Degree Grantor

University of Nevada, Las Vegas




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