Sleep, I view it as one of the most desired things by my peers in college. After a long week of school work, nothing is better to be able to sleep in for an absurd amount of hours, well past the recommended 8 or so hours. However, oversleeping does not result in the effects you might think, such as feeling well rested and more awake.
According to an article posted by Wired, our internal rhythms are set by our circadian pacemaker, which is a group of cells clustered in the hypothalamus. The pacemaker is primarily triggered by light signals from our eyes and is able to send out chemical messages keeping the cells of our bodies on the same schedule. According to this published article, circadian rhythms are believed to have adapted through natural selection resulting from the Earth’s rotation around its axis. For this reason, when you oversleep you are throwing off the circadian pacemaker. Although you are waking up later, your cells have started using their energy hours before.
Okay, so you oversleep a few times, not a big deal. If you oversleep (9-11 hours) on a regular basis however, you may develop memory problems. Other studies have concluded that oversleeping can put you at a greater risk of developing heart disease, diabetes, obesity and possibly even cause an early death.
A studies results posted in the Journal of the American Geriatrics Society came to the conclusion that extreme sleep durations over time appear to be associated with poor cognition in older women. They concluded this study based on a study of female nurses (N=15,385) aged 70 and older. They attempted to control some confounding variables such as stroke and depression by making sure they had no history of either at the initial cognitive assignment. The study however only looks at older women, and concludes data only on “extreme sleep durations” which includes oversleeping and under sleeping. The study also fails to control many confounding variables such as head injury (potentially concussions), as well as the usage of alcohol and drugs, that could potentially effect the results. Despite these things, the results of the study had a p-value of less than .001, and the differences in cognition were said to be nearly equivalent to a two-year age difference.
In another study, based on the surveillance of over 50,000 adults over the age of 45, they were able to conclude that long sleepers (4.1% of participants) were significantly associated with obesity, FMD, CHD, stroke and diabetes. The study suggests however that the mental disorders also may mediate the relationships between sleep duration and chronic diseases. The study also concluded the need for more studies to be done to determine how sleep duration is associated with chronic diseases and obesity.
Overall, there appears to be evidence that provides a correlation between over sleeping and many negative effects such as obesity and memory loss. However, without further studies done, it is hard to conclude it being an exact causation. With the inability to control all confounding variables and the difficulty of making this type of research experimental instead of observational, a definite answer is going to be hard to come by.
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