start sleeping 8 hours every day

Almost all of us know that sleeping poorly takes its toll on us the next day, where thinking becomes a task that it’s not easy at allin addition to having fewer reflexes or simply being much more tired. However, what happens inside the body when we alter our hours of sleep goes far beyond simple fatigue and contributes (a lot) to our aging. This is what a monumental study has pointed out, putting figures on this phenomenon.

The essay. A recent investigation published in the prestigious magazine Nature has analyzed approximately 500,000 adults to find out how sleep duration affects our “biological age.” And the verdict, after measuring the state of almost all our systems, draws a very clear U-shaped curve: the sweet spot is between 6 and 8 hours a day.

The biological clock. What makes this study a milestone is not only its gigantic sample size, which gives it enviable statistical power, but its approach. And normally aging studies are based on very general blood markers, but now science has opted to cross-reference data from genomics, proteomics, metabolomics and medical images.

With all this information, what they have done is nothing more than create 23 different “aging clocks” that represent the state of 17 organs of the human body. This has allowed them to map in a coordinated way the relationship between the brain, which is affected by this lack of sleep, and the rest of the body.

A curve. The main finding of this article focuses on the fact that the relationship between sleep and the level of aging does not follow a straight line, but rather has a ‘U’ shape. This means that people who systematically sleep between 6 and 8 hours have a lower “biological age” compared to their chronological age, in addition to having better general health.

But at the extremes, both sleeping less than six hours and sleeping more than eight hours are associated with accelerated aging in most of the organs that have been analyzed.

Because? There are reasons for both excess sleep and not enough sleep that justify this accelerated aging. If we focus on people who sleep little, we must take into account that during sleep the brain expands its channels to “clean” the accumulated metabolic waste, which interrupting it can cause accelerated brain aging.

But in addition, lack of sleep increases the levels of pro-inflammatory molecules and we already know that inflammation sustained over time can cause irreversible damage to organs.

Also in excess. We may think that sleeping a lot is the best thing there is, but the reality is quite different, as this study points out. The reasons for this are that spending 10 hours in bed does not mean sleeping well for 10 hours, since people who sleep ‘a lot’ tend to have fragmented, superficial sleep with micro-awakenings. This means that they spend more time in light phases and less in the restorative sleep that we value so much.

But we must also keep in mind that sleeping for a long time can be a symptom of an underlying disease such as depressionsleep apnea or chronic inflammation that is not the cause of aging as such, but does cause great damage to the body.

There are nuances. Although the data on the table are quite robust, the study itself points out a crucial limitation that is often the Achilles heel of epidemiology: the association does not prove chance. This means that we don’t know if we age faster because we sleep too little or if we sleep too little because our body is aging due to an underlying disease.

As epidemiologists who have reviewed this type of literature point out, forcing a person to sleep 7 hours does not guarantee that their biological clock will suddenly turn back. Furthermore, the researchers themselves clarify that the interval of 6 to 8 hours is a population association. That is, it is what works on average for the human species, but it does not imply that this range is the strict and optimal dogma for the biological needs of each individual.

Images | gpointstudio in Magnific

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