Here’s How Many Hours of Sleep Per Night You Actually Need According to Scientists!

Here’s How Many Hours of Sleep Per Night You Actually Need According to Scientists!

According to new research, it is possible that you might be sleeping for too long at night and that is actually not good for you!

Of course, sleep is very important for a multitude of reasons and getting enough of it is crucial.

However, not getting enough sleep and sleeping for too many hours appears to be similarly damaging to your brain functions.

That’s right! Experts have been warning people that sleeping for too many hours can be bad for you so what’s the ideal amount of sleep adults actually need to be well functioning and rested during the day?

Well, according to official NHS guidance, most adult-aged people need at least 6 hours of sleep and at most – 9!

Newer studies, however, have shown that this may actually not be the case, with some people only needing as little as 4 hours of sleep per night in order to wake up all refreshed and ready to take on the day.

Washington experts have found that the opposite of not getting enough sleep could interfere with people’s cognitive function.

More precisely, the researchers proved that adults who sleep less than 4.5 hours per night as well as those who tend to sleep more than 6.5 hours each night have pretty equal risks of cognitive decline over time.

It’s important to note the participants in the study all struggled with poor quality of sleep.

Another thing they learned was that the impact of sleep duration on one’s brain has a similar effect to aging – one of the biggest risk factors for developing cognitive illnesses such as Alzheimer’s.

With that being said, the scientists concluded that sleeping between 4.5 and 6.5 hours per night is the perfect amount for adults.

Senior lecturer in psychology, Greg Elder, wrote in The Conversation that researchers are not clear on the reason why lack of sleep is linked to cognitive decline.

“One theory’s that sleep helps the brain flush out any harmful proteins that can build up during the day. So interfering with our sleep might interfere with our brain’s ability to get rid of them. Experimental evidence supports this – showing that just one night of sleep deprivation increases beta-amyloid levels in the brain of healthy people, temporarily,” he stated.

He went on to also say that the Washington study’s findings are rather surprising as most authorities on health, including the Centre for Disease Control and the NHS agree that adult people should be sleeping at least 6 hours per night.

 More precisely, he explained that: “The study showed sleeping longer than 6.5 hours was associated with cognitive decline in time – this is low if we consider older adults are recommended to get between 7 and 8 hours of sleep every night. It could be the case that it is not necessarily the length of the sleep that really matters, but the quality of the sleep when it comes to the risk of developing dementia.”

On the other hand, he said that it is important to note that all 100 participants in the study who slept for longer than 6 hours might have also been suffering from other issues not mentioned in the tests.

The research team made sure to adjust their findings for dementia-related factors but Elder stressed that those who have longer sleep hours might also suffer from pre-existing conditions which can contribute to their cognitive decline as well.

This possibility, however, was apparently not taken into account by the Washington researchers.

Elder says that “For example, this may include poor health, socioeconomic status and physical activity levels. All of these factors may explain why longer amounts of sleep were linked to cognitive decline.”

Furthermore, another study previously published in San Francisco, concluded that your ideal amount of sleep per night depends a lot on your genetics.

Louis Ptacek, a neurologist and the lead author of the study said that “There is a dogma in the field that everybody needs 8 hours of sleep, but our work confirms that the amount of sleep people need is different based on their genetics. Think of it as analogous to one’s height; there is no perfect amount of height, each person is just different. We have shown that the case’s similar for sleep.”

This team of researchers has been looking into sleep patterns for more than a decade and they studied people with FNSS (Familial Natural Short Sleep), which is the ability to function at one’s best capacity, finding that all of them have a preference for sleeping between 4 and 6 hours every night.

However, they also made sure to mention that studying the genes linked to sleep would actually be a lot like a “thousand piece jigsaw puzzle.”

They explained that “Sleep problems are common in all diseases of the brain. This makes sense as sleep is a complex activity. Many parts of your brain need to work together for you to fall asleep and then wake up. When these parts of your brain are damaged, it makes it much harder to sleep or get quality sleep.”


Katherine is just getting her start as a journalist. She attended a technical school while still in high school where she learned a variety of skills, from photography to nutrition. Her enthusiasm for both natural and human sciences is real so she particularly enjoys covering topics on medicine and the environment.

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