As individuals with sleep-related breathing disorders develop more severe symptoms, they also appear to burn more calories when resting, according to an article released on December 15, 2008 in Archives of Otolaryngology – Head & Neck Surgery, one of the JAMA/Archives journals.
Snoring, and sleep apnea are both examples of sleep-related breathing disorders, in which the patient’s airways are either partially or completely obstructed during sleep. There are several risk factors for these disorders, including obesity: “Obesity is a major risk factor for the development of sleep-disordered breathing, and changes in body weight are associated with changes in sleep-disordered breathing severity,” write the authors. However, they also note that the causality of this relationship is not known: “It is unclear whether weight gain is simply a cause of sleep-disordered breathing or whether sleep-disordered breathing may be associated with alterations in energy metabolism that, in turn, lead to weight gain and complicate the treatment of these two disorders that often coexist.” Notably, the resting energy expenditure, the portion of calories that are burned while one is resting, can affect the balance of energy intake and expenditure, perhaps influencing one’s body weight.
To investigate the resting energy expenditure in patients with sleep-related breathing disorders, Eric J. Kezirian, M.D., M.P.H., of the University of California, San Francisco, and colleagues conducted examinations of 212 adults with signs or symptoms of sleep-related breathing disorders. A medical history was taken for each patient followed by a physical exam, a period of sleep monitoring using polysomnography, and the determination of resting energy expenditure using an indirect calorimeter.
Of the total cohort, the average resting energy expenditure was 1,763 calories per day, and several effects related to sleep-disordered breathing were associated with increased expenditures, even after correcting for body mass index, which can also affect expenditure. Specifically, higher scores of apnea and hypopnea increased the expenditure.
The authors hypothesize that the resting energy exposure may be influenced by the previously studied natural responses of the nervous system to sleep-related breathing disorder symptoms. “This study advances our knowledge concerning sleep-disordered breathing and metabolic rates, but it does not define the connection between sleep-disordered breathing and body weight,” they write. “Body weight is determined by the balance between energy intake and expenditure. Although the findings of this study suggest that sleep-disordered breathing increases energy expenditure, it ignored two important aspects of this balance.”
They continue, noting the implications in other ares of health. “First, sleep-disordered breathing often results in fatigue and other decrements in daytime functioning that can limit physical activity. Second, this work does not specifically incorporate the emerging evidence that suggests that sleep-disordered breathing may alter energy intake, whether through hormonal or other mechanisms. Future research considering the effect of sleep-disordered breathing on body weight can include the effects on energy intake and expenditure.”
Resting Energy Expenditure in Adults With Sleep Disordered Breathing
Eric J. Kezirian; Ceyda E. Kirisoglu; Robert W. Riley; Edward Chang; Christian Guilleminault; Nelson B. Powell
Arch Otolaryngol Head Neck Surg. 2008;134(12):1270-1275.
Written by Anna Sophia McKenney