How much truth is there to the claim that one must sleep for eight hours to stay healthy?

 How much truth is there to the claim that one must sleep for eight hours to stay healthy?

For the elderly, a lack of sleep can increase the risk of falling out of bed and suffering bone fractures. It can also make them susceptible to neurological issues, such as memory-related disorders.

How much truth is there to the claim that one must sleep for eight hours to stay healthy?

Although it is said that adults need at least seven to eight hours of sleep, doctors note that the same duration is not suitable for everyone.

Studies show that sleep requirements vary based on age, the nature of one's work, health conditions, and sleep quality; therefore, the need cannot be strictly defined by a specific figure like seven or eight hours.

Sound, deep sleep is essential for a healthy body.

How much sleep is actually needed? The answer we most often hear is, "You must sleep for at least seven to eight hours."

Consequently, we have come to associate sleep with a specific number.

We check the clock when we get into bed at night. When the alarm rings in the morning, we calculate whether we have managed to get those seven hours. This kind of mental tallying goes on constantly.

Doctors emphasize the importance of adequate sleep for adults, recommending a minimum of seven to eight hours. Global health guidelines also advise adults to get sufficient sleep regularly. As a result, the idea that one *must* get seven to eight hours of sound sleep at night has become widely accepted.

But is the calculation of sleep really that simple?

Does everyone need to sleep for exactly seven or eight hours? Does every person's body determine its sleep needs in the same way? There is no single answer regarding when people should go to sleep and wake up. Some people start their work early in the morning, while others have to work at night.

While seven hours of sleep may suffice for some, others might require eight hours or more. Factors such as age, lifestyle, the nature of work, health conditions, and personal habits influence sleep requirements.

Therefore, the question arises: how scientifically accurate is the notion that everyone must sleep exactly seven to eight hours?

A report on a new study published by the BBC examines this very aspect of sleep. Drawing on various studies regarding the relationship between sleep duration, human health, and cognitive function, the report questions whether a single, fixed sleep duration can be prescribed for everyone.

First, let us understand why sleep is necessary.

According to Prof. Dr. Saroj Prasad Ojha, a psychiatrist at the TU Teaching Hospital, sleep is a natural bodily requirement. Humans cannot remain awake continuously for 24 hours. The body and brain remain active throughout the day; energy is constantly expended while working, walking, thinking, and engaging in various activities. Eventually, the body becomes fatigued and seeks rest.

Why does weight increase with insufficient sleep?

Dr. Ojha explains that sleep is one of the natural processes through which the body rests. He notes that although the body may appear inactive from the outside during sleep, various biological processes are occurring internally. Sleep plays a role in everything from repairing body cells to organizing the information the brain has gathered throughout the day.

Adequate sleep is also linked to memory, the ability to concentrate, mood, and the body's immune system. Therefore, Dr. Ojha states that sleep is not merely a time to relieve the day's fatigue but a vital biological process necessary to revitalize the body and brain.

Sleep Needs Vary by Age

Neurologist Dr. Kishor Kumar explains that sleep requirements vary according to age. Children and adolescents need more sleep than adults. Even among adults, experiences can differ based on the nature of work, health status, physical and mental condition, and sleep quality.

Thus, he argues that limiting the concept of sleep solely to a specific number of hours is an incomplete understanding.

A study has also indicated that, regarding various markers of biological aging, the optimal sleep duration ranges between approximately 6.4 and 7.8 hours.

Seven or Eight Hours?

Seven to eight hours is the most commonly cited duration regarding sleep. The American Academy of Sleep Medicine recommends that healthy adults aged 18 to 60 get at least seven hours of sleep regularly. This does not mean that every individual must sleep exactly seven or exactly eight hours; rather, what matters is getting adequate and consistent sleep.

In other words, simply sleeping for seven hours does not guarantee the body has received sufficient rest. It is not just the duration of sleep that matters, but also the quality of that sleep.

Do Not Dismiss the Habit of Sleeping Less

One often encounters people who claim, "I feel fully rested with just four or five hours of sleep." However, chronic sleep deprivation can take a toll on the body. Psychiatrist Dr. Basudev Karki notes that a lack of sleep can lead to fatigue, irritability, difficulty concentrating, and impaired memory the following day. According to him, there are many instances where a lack of sleep has led to serious car accidents and even fatalities among adults. Similarly, in the elderly, insufficient sleep can increase the risk of falling out of bed and sustaining bone fractures. It can also make them susceptible to neurological conditions, such as memory-related disorders.

However, one should not equate a habit of sleeping less with the rare condition or necessity where an individual genuinely requires very little sleep.

Some people may naturally require less sleep than others. Yet, most people... He points out that there is a difference between trying to accustom your body to less sleep through restriction and the body actually requiring less sleep.

What happens to the body due to a lack of sleep?

Our bodies do not become completely inactive while we sleep. Instead, many vital bodily processes are active during this time. The body recovers from the day's fatigue, regulates various biological functions, and processes the information the brain gathered throughout the day.

According to Dr. Pratik Kishor, a lack of adequate sleep can increase inflammation in the body. This condition raises the risk of cardiovascular health problems.

Sleep deprivation can also affect the body's ability to regulate blood sugar levels. Prolonged issues of this nature can impact the functioning of various organs.

Previous studies have also explored the link between sleep deprivation and biological aging. One study conducted by researchers at the University of California involved 29 older adults aged between 61 and 86.

During the study, participants were subjected to varying sleep durations. On one occasion, they were allowed to sleep for only about four hours—from 3:00 AM to 7:00 AM.

Researchers collected blood samples each morning to analyze physiological changes.

Tests conducted after nights of insufficient sleep revealed cellular damage and signs associated with premature aging.

Can't sleep? Change your lifestyle instead of taking medication.

Lead researcher Dr. According to Judith Carroll, significant biological changes can occur in the bodies of older adults after just a single night of insufficient sleep. However, she notes that one cannot conclude from such studies that a person instantly ages just because they slept less for one night.

The study suggests a link between sleep and the body's biological processes.

What about sleeping too much?

Experts argue that the notion "the more you sleep, the healthier you are" is incorrect. A study published in *Nature* linked not only insufficient sleep but also sleeping more than eight hours to certain biological aging markers and disease risks. Researchers demonstrated a "U-shaped" relationship, indicating increased risks associated with both short and long sleep durations. However, caution is warranted here as well.

Observing health issues in people who sleep a lot does not necessarily mean that excessive sleep caused those problems; an individual might be sleeping more because they are already ill. Therefore, researchers conclude that one should not hastily interpret the observed link between excessive sleep and health issues as a direct cause-and-effect relationship.

So, how many hours should one sleep?

There is no single answer—such as "seven hours for everyone" or "eight hours for everyone"—that fits everyone. Instead of worrying about hitting a specific "7–8 hour" target, one should focus on whether the sleep is sufficient and of good quality, and observe how the body responds.

Do you feel refreshed upon waking up? Do you feel unusually sleepy throughout the day? Is your sleep frequently interrupted during the night? Do you experience issues like snoring or breathing pauses? These signs are also important for determining whether your sleep is sufficient.

If you can wake up easily in the morning after seven hours of sleep, do not feel sleepy during the day, can focus on your work, and do not experience physical fatigue, then that amount of sleep may be adequate for your body.

However, if you feel sleepy throughout the day, experience fatigue, struggle to concentrate, or find it very difficult to wake up in the morning despite sleeping for seven to eight hours, experts advise paying attention not only to the duration of sleep but also to its quality and your overall health condition.