Sleep disturbances: one of the culprits of obesity-related cardiovascular risk?

Abstract

Growing evidence suggested that Sleep Disorders (SD) could increase the risk of developing obesity and could contribute to worsen obesity-related cardiovascular risk. Further, obesity per se has been reported to blunt sleep homeostasis. This happens through several mechanisms. First of all, the excessive adipose tissue at neck and chest levels could represent a mechanical obstacle to breathe. Moreover, the visceral adipose tissue is known to release cytokines contributing to low-grade chronic inflammation that could impair the circadian rhythm. Also, nutrition plays an important role in sleep homeostasis. High fat and/or high carbohydrate diets are known to have a negative impact on both sleep quality and duration. In addition, obesity predisposes to a condition called "obstructive sleep apnea" that has a detrimental effect on sleep. SD could increase the risk and/or could contribute to worsen cardiovascular risk usually associated with obesity. The chronic low grade inflammation associated with obesity has been reported to increase the risk of developing hypertension, type 2 diabetes and dyslipidemia. In turn, improving quality of sleep has been reported to improve the management of these cardiovascular risk factors. Thus, the aim of this manuscript is to provide evidence on the association of obesity and SD and on how they could contribute to the risk of developing cardiovascular risk factors such as hypertension, dyslipidemia and type 2 diabetes in obesity.

Fig. 1. Mechanisms of the association between sleep disorders (SD) and obesity.

SD could represent a risk factor for the onset of obesity and could contribute to the development or worsening of obesity-related cardiovascular diseases. SD is associated to increased daily fatigue that consequently results in decreased physical activity. In addition, SD induces hormonal derangements mostly represented by an increase in ghrelin and a decrease in leptin levels. This hormonal change results in an increased food intake, mostly represented by fat and carbohydrates at the expense of fiber intake. All these mechanisms contribute to weight gain and thus to the development of obesity.