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Date of Award
Master of Science (MS)
Department of Kinesiology
Abstract Purpose: The aim of this study is to assess autonomic function by analyzing heart rate variability (HRV) at rest and during submaximal exercise in OSA patients and a non-OSA control group. Methods: Subjects were classified as OSA (n=10) or non-OSA (n=16) based on results from an at-home sleep assessment. Height, weight, waist and neck circumferences, and body composition were collected during the first visit for each subject. Physical activity during the day and nocturnal movement were assessed over a period of 4 days, including 3 weekdays and 1 weekend day, using accelerometers. HRV and blood pressure were recorded at rest (visit 2) and during a submaximal graded exercise test (visit 3). HRV variables that were not normally distributed were log transformed before statistical analysis. Independent samples t-tests were used to establish differences between groups. Pearson correlations were calculated to determine relationships between OSA and HRV in terms of age and BMI. If there was a significant correlation between variables and age and/or BMI, then a repeated measures ANCOVA was used with age or BMI as the covariate. If there was not a significant correlation, a repeated measures ANOVA was utilized. Results: At rest, the OSA group had lower SDNN, RMSSD, and Total Power (p<0.05). A higher LF-HF ratio was found in the control group than the OSA group during exercise (p<0.05). LFnu and HFnu were trending towards significance, both higher in the OSA group (p=0.066 and p=0.075, respectively) during exercise indicating that the OSA group did not experience parasympathetic withdrawal. All subjects participate in about 30 minutes of moderate physical activity daily. Discussion: Results suggest that the OSA population may have increased autonomic dysfunction during exercise due to sympathetic dominance and a blunted parasympathetic response during steady-state exercise. Potential mechanisms for autonomic imbalances include decreased chemoreceptor and baroreceptor sensitivity. Further research with a larger OSA sample group is necessary.
Sutton, Courtney, "The effects of obstructive sleep apnea on autonomic function during steady-state exercise" (2014). Masters Theses. 344.