Daytime Sleepiness in Obesity: Mechanisms Beyond Obstructive Sleep Apnea—A Review

Abstract

Increasing numbers of overweight children and adults are presenting to sleep medicine clinics for evaluation and treatment of sleepiness. Sleepiness negatively affects quality of life, mental health, productivity, and safety. Thus, it is essential to comprehensively address all potential causes of sleepiness. While many obese individuals presenting with hypersomnolence will be diagnosed with obstructive sleep apnea and their sleepiness will improve with effective therapy for sleep apnea, a significant proportion of patients will continue to have hypersomnolence. Clinical studies demonstrate that obesity without sleep apnea is also associated with a higher prevalence of hypersomnolence and that bariatric surgery can markedly improve hypersomnolence before resolution of obstructive sleep apnea. High fat diet in both humans and animals is associated with hypersomnolence. This review critically examines the relationships between sleepiness, feeding, obesity, and sleep apnea and then discusses the hormonal, metabolic, and inflammatory mechanisms potentially contributing to hypersomnolence in obesity, independent of sleep apnea and other established causes of excessive daytime sleepiness.

High fat diet induces specific pathological changes in hypothalamic orexin neurons in mice

“…This fact should be taken into consideration for explaining the mechanisms of loss of orexin neurons observed in humans suffering from various types of neurological disorders including narcolepsy. Besides, HFD intake is associated with hypersomnolence (Panossian and Veasey, 2012), and has been found to alter circadian feeding pattern and cause deficits in reward system (Morales et al, 2012). Given that orexins have been shown to play important roles in regulation of arousal, food intake and rewarding system (Sakurai and Mieda, 2011), HFDinduced pathology in orexin neurons, demonstrated in the present study, may contribute to these alterations in systemic functions.…”

Effect of biliopancreatic diversion on sleep quality and daytime sleepiness in patients with obesity and type 2 diabetes

“…The complex interrelationships between circulating systemic hormones and neuronal signaling pathways in the central nervous system are involved in this process. Obesity and metabolic syndrome are related with atypically raised basal levels of sympathetic nervous system activity, which may have the potential to fragment sleep and contribute to daytime sleepiness (16).…”

Are sleep duration and sleep quality associated with diet quality, physical activity, and body weight status? A population-based study of Canadian children

“…26,27 These associations are not surprising given that snoring and daytime sleepiness are both common symptoms of obstructive sleep apnea, a sleep disorder that is more prevalent among children who are overweight or obese. 26,27 The observed independent association between snoring and weight status in this study may be explained by the higher risk for sleep disorders among overweight or obese children, where snoring is indicative of the presence of a sleep disorder. Future analysis where there is a diagnosis of a sleep disorder is needed in order to increase understanding of this relationship, however this study has helped to further clarify the magnitude of compromised sleep among Canadian children.…”