As society has evolved during the past decade, there have been significant increases in body weight in the United States, along with other developed countries. The National Health and Nutrition Examination Survey shows that 127 million people are overweight, which is described as having a body mass index (BMI) between 25 kg/m2 to 30 kg/m2, 60 million individuals are obese (BMI > 30 kg/m2), and 10 million people are morbidly obese (BMI > 40 kg/m2). About 325,000 people die annually due to obesity related disorders, such as cardiovascular disease (CVD). Body weight is increasing due to many factors, particularly a lack of physical activity and unhealthy diets, which are producing increased incidence of Metabolic Syndrome, insulin resistance, diabetes and CVD (Esposito et al., 2006). Abdominal obesity can cause increases in cytokine release by fat tissue, leading to the previously mentioned disorders. Not only are adults suffering from obesity, but obesity in children is trending in the same direction. This has become quite a public health problem not only in the United States, but also in most European countries, with 20% of Southern, Central and Eastern European adults being obese. The Middle East has remarkably high obesity rates and is also the region, with the highest national prevalence of insulin resistance and type II diabetes in the world. Asian and African populations have also shown dramatic reductions in physical activity levels, as well as alterations in dietary intake adding to the already increasing obesity prevalence in developed countries (James, 2008).
Sleep loss and restriction have been associated with changes in energy balance and can result in overall weight gain, as well as the development of obstructive sleep apnea syndrome (OSAS). OSAS is a disorder defined as a repeated collapse of the upper airway, resulting in cessation of breathing even though respiratory effort continues. OSAS is also characterized by an apnea hypopnea index (AHI) of greater than 5, representing the average amount of times an individuals breathing ceases in an hour of sleep. This leads to arousal from sleep resulting in sleep fragmentation, and sleep deprivation (Keller at al., 2007). Sleep deprivation may cause changes in appetite regulation due to disturbances in glucose etabolism, as well as reducing motivation to exercise and increase dietary intake due to elevated leptin levels (Knutson et al., 2007). Van Cauter and associates (2007) found that healthy young subjects who are sleep deprived, have alterations in their neuroendocrine control of appetite. This then can lead to increased hunger and changes in glucose tolerance that result in an increased risk for the development of diabetes.
Obesity is one of the strongest risk factors for OSAS, which includes an increase in body weight traits such as body mass index (BMI), waist/hip ratio, neck circumference, percent body fat, and skin fold thickness (Sharma et al., 2006). These characteristics have been studied in the middle-aged male population, with little attention being concentrated on younger adults. Weight loss is recommended for those who are overweight with OSAS to help improve CVD risk (Esposito et al., 2006). However, the relationship between obesity and OSAS is still unclear; this may be attributed to the complexity of feeding regulations that are controlled by the central nervous system (Cherinack, 2005).
