The purpose of this thesis project was to examine the trajectories of physical activity among newly-diagnosed Obstructive Sleep Apnea (OSA) patients within the UC+WS group of the SleepWell24 study across the first 60 days of CPAP use, alone and based on Apnea-Hypopnea Index (AHI), Body Mass Index (BMI), sex, and age. The study utilizes objective data from the SleepWell24 randomized controlled trial conducted by a collaborative research team at Arizona State University and Mayo Clinic Arizona and Rochester. Participants use wearable sensors to track activity behaviors, such as sleep, sedentary behavior, light-intensity physical activity (LPA), and moderate-vigorous physical activity (MVPA). The primary aim of the study was to examine the physical activity trajectories among newly-diagnosed OSA patients over the first 8 weeks of CPAP use, utilizing the physical activity data from wearable sensors. The secondary aim was to assess the trajectories of physical activity between categories of AHI, BMI, sex, and age. Multilevel modeling was used to account for clustering within participants considering between and within subject variations, and week was used as a level 1 predictor in the model for LPA, and MVPA, and total activity (sum of LPA and MVPA), while between subject factors of BMI, sex, age, and AHI were also included in the model. It was found that there were no statistically significant trajectories of LPA, MVPA or total activity over the first 8 weeks of CPAP use within the sample of 30 participants. However, a few notable differences in physical activity were seen between categories of age, sex, and BMI. Also, there was a significant interaction found between BMI and each week that influenced the trajectory of physical activity within obese patients, as compared to participants considered overweight or with a lower BMI. Ultimately, this study provides insight into patterns of physical activity seen in a clinical population of OSA patients over the initial period of CPAP use.