Date of Award

1-1-2010

Document Type

Campus Access Dissertation

Department

Exercise Science

First Advisor

Shawn D. Youngstedt

Abstract

Obstructive sleep apnea (OSA) is a prevalent and harmful sleep disorder, with numerous health consequences if left untreated. Available treatment options are either suboptimal in efficacy or undesirable due to side effects. Despite intriguing preliminary epidemiologic and experimental evidence, the efficacy of exercise training has been scarcely explored for the management of OSA. These studies were designed to establish the efficacy of exercise training on (1) OSA severity and overall sleep quality, (2) daytime functioning and neurobehavioral performance, and (3) markers of cardiovascular health risk, as assessed by cardiopulmonary exercise testing (CPET) and the inflammatory biomarker C-reactive protein (CRP). Forty-three sedentary adults aged 18-55 years with at least moderate-severity OSA (screening apnea-hypopnea index [AHI] ¡Ý 15) were randomized to an exercise training treatment (n = 27) or a low-intensity stretching control treatment (n = 16). Participants assigned to the exercise training treatment met 4 times per week for 12 weeks and performed 150 min/week of aerobic activity at 60% of heart rate reserve and 2 days/week of resistance training involving 2 sets of 10-12 repetitions for 8 exercises. Participants assigned to the stretching treatment met twice per week for 12 weeks to perform a ~30-min stretching program designed to increase whole-body flexibility. Following the intervention, in which no significant weight loss occurred, exercise training resulted in a significant reduction in AHI relative to stretching control (P < 0.01) as well as significant changes in the oxygen desaturation index (P = 0.03) and NREM stage 3 sleep (P = 0.03). Similarly, significant improvements in actigraphic and subjective sleep quality were also noted following exercise training. Moderate improvements in aspects of daytime functioning (Hedges¡¯ g > 0.50), such as sleepiness, feelings of vigor and fatigue, depressive symptoms, and quality of life were likewise found following exercise training compared to control treatment. When compared to an age- and body mass-matched group of adults without OSA (n = 9), those with OSA had a significantly blunted heart rate recovery (HRR) at baseline. Following exercise training, significant improvements were noted for HRR (P < 0.03), cardiorespiratory fitness (P = 0.04), and CRP (P < 0.05) compared to control. These data indicate that exercise training without weight loss results in significant, albeit modest, improvements in OSA severity. Furthermore, improvements in daytime functioning and markers of cardiovascular health risk following exercise training were found to be largely independent from improvements in OSA severity. Overall, these results provide additional evidence regarding the possible utility of exercise training in the management of OSA severity and its health consequences.

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