Approximately two-thirds of all adults in the United States are estimated to be overweight or obese. No demographic group has been spared;increased rates of obesity have been documented in all age groups, in both sexes, and among all ethnic groups. Explanations for the dramatic increase in obesity include increasingly sedentary lifestyles, and changes in food manufacturing and marketing practices, the increased use of central heating and air conditioning, increasing gravid age, decreased smoking rates, and decreased sleep durations. Sleep loss due to voluntary curtailment of sleep is common among Americans of all ages. Numerous epidemiologic studies have revealed a dose-dependant relationship between reduced sleep duration and increased body mass index (BMI). In addition, well-controlled laboratory studies have documented that sleep loss appears to up-regulate appetite by altering the ability of metabolic hormones to accurately signal caloric need, alters glucose metabolism and increases insulin resistance, and elevates blood pressure. It has been suggested--but never tested--that extending sleep will facilitate weight loss. Therefore, the goal is of this project is to lay the groundwork for a future clinical trial testing the hypothesis that healthy obese individuals who obtain at least 7.5 hours sleep per night will loose more weight than healthy obese adults obtaining 6.5 hours sleep per night. Specifically, the goals of this project include: 1) feasibility testing of a sleep extension protocol as an adjuvant to traditional weight loss programs;2) comparing the efficacy of sleep extension in combination with caloric restriction and exercise to a traditional weight control program consisting of caloric restriction and exercise for facilitating weight loss in obese individuals;3) comparing the efficacy of a sleep extension protocol in combination with caloric restriction and exercise to a traditional weight loss program consisting of caloric restriction and exercise to a traditional weight loss program consisting of caloric restriction and exercise for normalizing glucose levels and blood pressure in healthy obese individuals;and 4) explore the effect of sleep extension on leptin and ghrelin levels. The sleep extension protocol will utilize the same principles as the behavioral modification protocol already in use at Temple University's Center for Obesity Research and Education e.g., making incremental but sustainable changes in behavior, setting weekly behavioral goals, self-monitoring of progress towards goals, identification of barriers, etc., and will be incorporated into weekly group meetings.
Approximately two-thirds of all adults in the United States are estimated to be overweight or obese. Since even moderate amounts of excess weight are associated with increased morbidity and mortality, additional strategies are needed to combat the growing obesity epidemic. This study represents a beginning step in determining if extending sleep would assist individuals in loosing weight.
