Tag Archives: Proceedings of the National Academy of Sciences

Why you need at least 6 hours of sleep a night

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Chronic sleep deprivation makes us vulnerable to a host of illnesses. Sleep deprivation is defined as less than six hours of sleep per night.

Here’s why.

Nick Collins reports for The Telegraph, Feb. 25, 2013, that a new study by scientists from the UK’s Surrey University found that just one week of sleep deprivation can “switch off” hundreds of genes that play a key role in the body’s constant process of self-repair and replenishment, thereby raising the risk of a host of illnesses including obesity and heart disease.

Those reparative genes produce a constant supply of proteins which are used to replace or repair damaged tissue, but after a week of sleep deprivation some of these stopped working.

Studies have also shown a lack of sleep can lead to cognitive impairment, for example limiting our ability to drive a car safely.

Scientists from Surrey University divided 26 volunteers into two groups, one of which slept for less than six hours per night for an entire week, and one which slept for ten hours per night.

At the end of the week each group was kept awake for 40 hours and donated blood samples, which were studied to examine the effects of their sleep regimes.

The week of sleep deprivation was found to have altered the function of 711 genes, including some involved in metabolism, inflammation, immunity and stress. Inadequate sleep also interfered with genes which are designed to become more or less active at certain points in the day, by throwing off the body’s 24-hour internal clock.

Happily, a week of normal sleep restores the affected genes to their normal pattern. But prolonged periods of sleeplessness could lead to serious health problems including obesity and heart disease.

Prof Colin Smith, one of the authors of the new paper, which was published in the Proceedings of the National Academy of Sciences journal, said: “This is only a week of sleep restriction and it is only five and a half or six hours a night. Many people have that amount of sleep for weeks, months and maybe even years so we have no idea how much worse it might be. If these processes continue to be disrupted, you could see how you are going to get impairment of organs, tissues, heart disease, obesity, diabetes. If you are not able to replenish cells and tissues that are damaged then you are going to suffer permanent ill health.”

See also “Sleeping for more than nine hours may help weight loss: research,” May 1, 2012.

~Eowyn