During the past few decades sleep behavior has deteriorated very much, particularly among Americans, sleep curtailment becoming highly prevalent. A number of survey studies have been conducted on the subject in the US since 1960 that unquestionably proved the downside tendency of sleep duration.
The prevalence of obesity increased over the past 2-3 decades all over the world and continues to increase despite the fact that fighting weight gain turned into a contemporary challenge and almost became a cultural pattern. In the same time the prevalence of diabetes increased at an alarming rate, the two phenomena being connected in some way (obesity is a risk factor of type 2 diabetes, just to name one connection).
The researchers found something truly intriguing … During the past few decades sleep behavior has deteriorated very much, particularly among Americans, sleep curtailment becoming highly prevalent. A number of survey studies have been conducted on the subject in the US since 1960 that unquestionably proved the downside tendency of sleep duration. In 1960, a study led by the American Cancer Society found modal sleep duration to be 8.0 to 8.9 hours while in 1995 the National Sleep Foundation survey indicated, in its modal category, 7 hours sleep duration, which means one hour of sleep less. Later studies indicate that a great percentage of adult Americans do not sleep more than 6 hours every night! Today 30 % of adult men and women between 30 and 64 report less than 6:00 per night sleep.
The two aspects, short slip and prevalence of obesity and type 2 diabetes, have emerged in the same period of time and had a similar evolution, therefore the researchers examine the hypothesis that a connection between them exists. However, the medical world agrees that the causes of this pandemic are not completely explained by changes in traditional lifestyle factors, such as diet and physical activity ... The short sleep appears to be an alternate cause, currently under the researchers’ investigation.
But what would be the mechanisms connecting the two phenomena? Firstly, short sleep may impair glucose metabolism and increase the risk of diabetes independently of changes in body mass index (BMI), obesity being in itself a risk factor for type 2 diabetes. Secondly, short sleep may affect the energy balance of the body, thereby causing an up-regulation of appetite, more time to eat and a decrease in energy expenditure. Thirdly, significant weight gain may turn in insulin resistance, a condition that increases the risk of developing diabetes and may promote further adiposity.
Many studies conducted in the last period of time, focused on target groups from different geographical areas and having different cultures and lifestyles, have shown that there is a direct link between short sleep (or poor quality sleep), obesity and the risk of developing diabetes in particular among men. The studies also indicated that there is a direct link between short sleep and too much food ingestion, unhealthy food habits (snacks between meals, not enough vegetables and fruits and others).
However, the final, undeniable conclusions aren’t available yet given that there are too many factors that contribute to these mechanisms, which are very subtle! Still, the figures resulted from studies are undeniable and strongly sustain the connection.
More at U.S. National Library of Medicine, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1991337/