The Role of Physical Activity and Exercise in Sleep-Disordered Breathing

Abstract

Introduction: Sleep-disordered breathing (SDB), particularly obstructive sleep apnea (OSA), is a major public health concern, affecting around one billion adults globally, with obesity as a key risk factor. Fat distribution in the neck and abdomen, in addition to physical inactivity and sedentary behavior, contribute to its severity. OSA disrupts sleep, reduces sleep quality, causes daytime sleepiness, and significantly impacts physical health and well-being. While positive airway pressure therapy is the gold-standard treatment for moderate-to-severe OSA, limited options exist for milder cases. Exercise interventions have shown promise in reducing OSA symptoms, especially in moderate-to-severe cases, while lifestyle mobile applications (apps) have been shown to promote weight loss. Objectives: The overall objectives of this doctoral thesis were: (i) To explore the differences in the role of physical activity (PA) in individuals with OSA by examining both subjectively and objectively measured PA, and to study PA as a predictor of OSA severity; and (ii) to evaluate the effects of two distinct interventions, a structured exercise program and a lifestyle app, on various SDB-related and health parameters including SDB severity, anthropometry, body composition, physical fitness, health-related quality of life (HRQoL), and sleep health in 18-50-year old individuals with mild to moderate SDB. Methods: In Paper I, 65 participants (49.2% males) were assessed to determine the relationship between OSA severity and daily PA. Participants were categorized into three OSA severity groups: no, mild, and moderate-to-severe OSA. Participants completed anthropometric measurements, body composition, apnea-hypopnea index (AHI), and a desaturation parameter (DesSev+RecSev), wore a smartwatch for one week, and completed a PA questionnaire and daily exercise logs in a sleep diary. In Papers II and III, 192 participants (52.6% male) were enrolled in a 12-week randomized controlled trial evaluating the effects of exercise and lifestyle app interventions. Participants underwent comprehensive measurements pre- and post-intervention. The measurements included AHI and snoring, anthropometry, body composition, physical fitness, HRQoL questionnaire, and sleep health (subjective and objective measurements). The exercise intervention involved supervised 60-minute circuit training and brisk walking sessions three times per week, while the lifestyle app intervention included daily tasks focused on diet, PA, stress management, and sleep. Results: Participants with moderate-to-severe OSA underestimated their sitting time compared to objectively measured PA, a discrepancy not observed in participants with no or mild OSA. PA was not a predicting factor for OSA severity, whereas age, body mass index (BMI), and body composition were significant predictors. A no-to-weak correlation was found between objective and subjective PA measures. The 12-week exercise intervention reduced AHI and increased skeletal muscle mass, physical fitness, and HRQoL in four domains. In addition to improvement in subjective sleep health, reflected in the Pittsburgh Sleep Quality Index (PSQI) global score and three PSQI subscales. The lifestyle app program reduced weight, BMI, neck circumference, body fat, visceral adiposity, and skeletal muscle mass while improving three HRQoL domains. Further, subjective sleep health was enhanced, particularly in the daytime dysfunction subscale of the PSQI, in addition to changes in objective sleep health, reflected in reduced wake after sleep onset (WASO), increased light sleep (N2), and decreased deep sleep (N3). Conclusions: The overall conclusions were: (i) Individuals with moderate-to-severe OSA tended to underestimate their sedentary time, with subjective PA assessments misaligning with objective measurements. PA was not a predictor of OSA severity after accounting for age, BMI, and body composition. (ii) Both structured exercise and lifestyle app interventions benefited but had distinct effects. The 12-week exercise program reduced AHI, increased skeletal muscle mass, and improved physical fitness, HRQoL, and subjective sleep health, without changes in anthropometry. In contrast, the lifestyle app intervention promoted improvements in anthropometry, body composition, and HRQoL and influenced both subjective and objective sleep health parameters, but did not lower AHI and led to muscle mass reduction.