Weight Loss and Sleep, Current Evidence in Animal Models and Humans

Abstract

Sleep is a vital process essential for survival. The trend of reduction in the time dedicated to sleep has increased in industrialized countries, together with the dramatic increase in the prevalence of obesity and diabetes. Short sleep may increase the risk of obesity, diabetes and cardiovascular disease, and on the other hand, obesity is associated with sleep disorders, such as obstructive apnea disease, insomnia and excessive daytime sleepiness. Sleep and metabolic disorders are linked; therefore, identifying the physiological and molecular pathways involved in sleep regulation and metabolic homeostasis can play a major role in ameliorating the metabolic health of the individual. Approaches aimed at reducing body weight could provide benefits for both cardiometabolic risk and sleep quality, which indirectly, in turn, may determine an amelioration of the cardiometabolic phenotype of individuals. We revised the literature on weight loss and sleep, focusing on the mechanisms and the molecules that may subtend this relationship in humans as in animal models.

Keywords: OSAS; bariatric surgery; metabolism; obesity; sleep; weight loss.

Figure 1

Correlation between sleep and obesity. HPA axis: hypothalamic–pituitary–adrenal axis.

Figure 2

Sleep alterations and body weight loss in animal studies. Studies in animals, mainly rodents, are an easy and feasible way of studying the physiology of sleep and energy homeostasis to identify therapeutic targets; however, it is important to remember that rodents are nocturnal creatures, and their sleep/wake cycle is the opposite of humans. Obese and diabetic mouse models showed alterations in sleep architecture, mainly an increase in sleep time, similar to humans. Some molecules regulating energy homeostasis can also influence sleep patterns and, at the same time, control body weight. Some approaches used to reduce body weight, such as active time-restricted feeding (ATRF), food caloric restriction or bariatric surgery, positively affect sleep patterns; however, the mechanisms underlying these effects need to be elucidated (figure created with BioRender.com, accessed on 14 December 2022). Red arrows: negative effect, green arrows: positive effect.

Figure 3

The impact of bariatric surgery on obesity and sleep. OSAS: obstructive sleep apnea syndrome. Up arrows: increase, Down arrows: decrease.