The first PhD thesis defence within the Department of Sport Science

Katrín Ýr Friðgeirsdóttir completed her PhD thesis defence on May 12th from the Department of Sport Science. Her thesis is titled: The Role of Physical Activity and Exercise in Sleep-Disordered Breathing. This was the first PhD thesis defence within the department.

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 behaviour, contributes 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.     

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.         

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.

The Main Supervisor was Dr. Jose M. Saavedra, Department of Sport Science, Reykjavik University, Iceland. Co-Supervisor was: Dr. Erna Sif Arnardóttir, Department of Computer Science & Department of Engineering, Reykjavik University, Iceland.

Members were Dr. Anna Sigríður Islind, Department of Computer Science, Reykjavik University, Iceland. and Dr. Damir Sekulic, Faculty of Kinesiology, University of Split, Croatia.

Examiners were Dr. Sabrina Forster, Sportwissenschaftlerin, Institut für Sport und Präventivmedizin, Universität des Saarlandes, Saarbrücken, Germany. and Dr. Yves Dauvilliers, Sleep and Wake Disorders Centre, Department of Neurology, Gui de Chauliac Hospital, Montpellier, France

Master of Ceremonies was Dr. Hafrún Kristjánsdóttir, Chair of the Department of Sport Science.