Despite the recent advances made in the arena of obesity and its links to sleep deprivation, significant knowledge gaps remain in place and continue to hinder the application of public health’s understanding of this issue to real-world problems. While there is not a single study in the literature in which the authors have examined the relationship between sleep deprivation and obesity and failed to report a significant association, there is significant confusion as to the direction (or even as to the existence) of causality between the independent and dependant variables.
One study’s authors report that “there was a dose dependent decrease in the proportion of overweight and obese children by duration of sleep” (von Kries, Toschke, Wurmser, Sauerwald, & Koletzko, 2002, p.714). Dose-response mechanisms are one of the primary qualities for which one should look when determining the level of causality according to the Bradford Hill criteria (Friedman, 2005). However, the same study later reveals that “reduced sleep might at least possibly be rather a consequence of overweight and obesity than its cause,” noting as a potential reason the fact that “exercise may account for better and longer sleep;” a problematic interaction in terms of determining causality because exercise is also known to be independently associated with weight loss (von Kries et al., 2002, p.714).
This same uncertainty is echoed in nearly every article in the literature. Another study’s authors conclude a discussion of the effects of changes in ghrelin and leptin levels on BMI by writing that “these changes can be hypothesized to play a contributory rather than compensatory, role in the development of overweight and obesity with sleep restriction” (Taheri, Lin, Austin, Young, & Mignot, 2004, p.214). Two additional studies strongly suggest the need for additional research into the relationship between the independent variable and the dependent variables (Vorona, Winn, Babineau, Eng, Feldman, & Ware, 2005; Spiegel, Tasali, Penev & Van Cauter, 2004).
Jennifer Altman concludes her summary of a conference in Neuroendocrinology with the assertion that “As ghrelin and leptin have such a broad palette of actions, it is not surprising that so many conundrums and paradoxes remain in this young field”
(2002, p.135). Now that we have a rudimentary understanding of the interaction between sleep deprivation, leptin, ghrelin, and BMI, the field is ready for a more rigorous study of the phenomenon at hand.
Public health and the associated medical fields have only recently begun to examine the relationship between sleep deprivation and overweight and obesity. Because the prevalence of overweight and obesity has increased so dramatically in the past 15 years (Bass & Turek, 2005), and because the consequences of this epidemic are so severe, including complications such as “insulin resistance and type 2 diabetes mellitus, hyperlipidemia, cardiovascular disease, hypertension, stroke, cancer, and arthritis” (Bass & Turek, 2005, p.15), much focus has been placed on overweight and obesity in the scientific literature. However, before the year 2000, most of this research examined sleep deprivation as a potential confounder or mediating variable in other relationships (such as between sedentary behavior and obesity).
Recent journal articles have noted that that the upward trend of obesity mirrors the increasingly severe trend of sleeplessness, especially among working class, where “49% of shift workers stated that, while working, they slept 6.5 hours or less… compared to estimates that the average American slept about 9 hours per night a century ago” (Vorona et al., 2005, p.25). This casually noticed, parallel trend has led to more rigorous investigation of the relationship between the two variables in the recent past, and several studies are still being processed. Only in 2004 did the Journal of the American Medical Association (JAMA) acknowledge the parallel trend between self-reported hours of sleep and obesity as a potential area of study, noting that “sleep deprivation and sleep disorders are comorbid or causative factors of diabetes and obesity” (Lamberg, 2004, p.2517).
What does this mean for the "average" person? If you are concerned about your weight and you have an irregular or short sleep schedule, it is entirely possible that your activities directed toward weight loss should include regulating your sleep schedule and ensuring that it lasts about nine hours.
very good atricle. see the link
I am convinced that you need to do a lot more reading on breakthrough research that has been PUBLISHED in main MEDICAL JOURNALS, endorsed by scientists and top Universities that have been involved in ascertaining the OBVIOUS and undisputed link between sleep deprivation and obesity. Have you not heard of 2 hormones named LEPTIN and Ghrelin???
Leptin is a protein hormone that controls weight gain by decreasing appetite and regulating the energy burning process of the body.
Ghrelin on the other hand is a hormone made by cells in the stomach and is the ONLY known hormone that stimulates hunger.
Lack of sleep increases the ghrelin hormone while leptin experiences an increase.......
This study was supported by the Division of Sleep Medicine of the Department of Internal Medicine and the Department of Family Practice of Eastern Virginia Medical School and by the office of Dr. Feldman.
Also, many different international studies were published since the past 2 years and are available by visiting www.archinternmed.com . The university of YALE - bulleting & calendar - April 22, 2005 - volume 33 number 27 - has published an important article called " Link between stress, insomnia and obesity shown."
New research from the University of Wisconsin-Madison, Stanford University and the University of Chicago are boosting earlier findings of a relationship between sleep and weight: The less sleep a person gets, the more weight is gain.
Two new studies suggest that what's not happening in the bedroom may be a key factor into why so many of us are gaining weight.
The studies published in the Annals of Internal Medicine found a link between sleep deprivation and obesity. They show that when we're sleep deprived, a chain reaction begins in our hormone levels that appear to lead to bigger appetites and increased levels of body fat.
That's what researchers at the University of Chicago found after testing 12 men who were allowed just four hours of sleep for two nights in a row. They discovered a drop in leptin, a hormone that makes you feel full, and a sharp rise in ghrelin, a hormone that stimulates appetite.
"The study is important it shows a link between not sleeping enough and perhaps overeating," says study leader Dr. Eve Van Cauter, a professor of medicine at the University of Chicago. "And this is a major problem in this country particularly because we have an epidemic of obesity."
There are many more referenced studies that are available. Many new companies are basing their marketing strategies around products that work synergistaically to provide better health and added safe sleep WITHOUT chemical compounds, all natural botanicals. One such company is Our World Network based in Vancouver, Canada. They are the only company that I know of, that has addressed the link between sleep and obesity by specifically designing 2 natural products named SKINNEES and SLEEPEES. They are establishing an impressive presence in a very short time because their products work!
This is a very important subject. It affects the vast majority of young people that represent our future. We need to be better informed of ways to curb and control these very unhealthy tendencies we have indulged in .
I believe that many of the issues with which I would take with your comment are self-evident, but one is not:
There is a difference between a correlation and a causative relationship. I assume that you are familiar with the "Bradford Hill" criteria of causation established in the mid 1960s, a document that has since become the standard for scientific studies attempting to prove a causal link between two variables. My point was that, while there is certainly a correlation between sleep deprivation and obesity (involving ghrelin and leptin, which I noted in my article as being mediating biological variables), very few, if any of the studies in the literature have established a concrete causal link.
In the 4th paragraph from the top please correct to read: "Lack of sleep increases the ghrelin hormone while leptin experiences a decrease...
thank you Genevieve Ward
In the 4th paragraph from the top please correct to read: "Lack of sleep increases the ghrelin hormone while leptin experiences a decrease...
thank you Genevieve Ward
that's interesting.
it's weird cause i get like 5 hours of sleep a night and i'm thin.