Health, Lifestyle

Fragmented sleep

If, after four hours of sleep, you wake up in the middle of the night, do not worry. Find a book to read or think of another activity to do because it is very likely that a couple of hours later you will fall back to sleep for another four hours.


Juliett Morales García

Our prevailing mindset that it is good to sleep for a solid eight-hour block could be unnatural and could be the cause of some sleep disorders.

For experts such as Thomas Wehr, who have investigated sleep for decades, it is normal for sleep to be fragmented because the body tends to maintain a pattern of rest and wakefulness.

He explains that it is natural to sleep for four hours, then be awake for one or two hours before going back to sleep again for about another four hours.

Fragmented sleep is nothing new, as the historian Roger Ekirch, from Virginia Tech, wrote in his book At day’s close: night in the past, published in 2001.

His book collates 16 years of research that revives more than 500 references about the custom of sleeping in two slots.

An example of this habit can be found in El ingenioso Hidalgo Don Quijote de La Mancha by Miguel de Cervantes y Saavedra.

“Don Quijote complied with nature, sleeping a first sleep, but without giving way to a second, the opposite of Sancho, who never had a second, because his sleep lasted from night until morning, when he surfaced with a fine complexion and without a care, ” said the expert.

A long time earlier, the poet Homer referred to divided sleep in the Odyssey. Charles Dickens also mentioned it in his work Barnaby Rudge, he said.


In times gone by, everyone used the two usual waking hours to do whatever they wished.

In those times, some would visit neighbours, smoke, go to the bathroom, write, pray or enjoy the pleasures of the flesh; it was said that it was better to conceive in the early hours rather than late at night.

When this became an opportune time to carry out various activities, night-life began to become popular.

With public lighting in the form of candle wax in glass lamps and the proliferation of cafes, night-time took on a certain status and it was considered a waste of time to stay in bed.

Proof of this can be found in a medical journal that advised parents to get their children used to not sleeping beyond their first sleep. “Except in the case of illness or accident, they do not need more rest than is offered by the first sleep and they should get used to it ending naturally at the normal hour.

Then, if they try to go back to sleep, you must teach them that that is a bad habit that will be of no benefit to them,” the old medical guide noted.

Changing patterns

In the late 17th century, references to the first and second sleep started to disappear and by the second decade of the 20th century the concept vanished completely.

Nowadays, people have adapted to sleeping eight hours continuously, but Ekirch believes that many sleep disorders could be explained by the tendency of the body to fragment sleep, and because of the existence of artificial light.

According to the historian, this could be the cause of so-called sleep maintenance insomnia, a problem that sees those affected have difficulties in getting back to sleep after waking up in the middle of the night.

The first references to this problem started to appear in the late 19th century, when the habit of fragmented sleep was going out of fashion.

Russell Foster, a professor at Oxford University, also believes that the belief of sleeping eight hours continuously is harmful.

It is thought that fragmented sleep creates a natural mechanism of regulating stress.

Because of that, if you open your eyes spontaneously in the middle of the night, do not worry, simply relax, because after two hours Morpheus should return and you will sleep peacefully in his arms.

(Translated by Victoria Nicholls)

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