Sleeping little or too much accelerates aging: here's the ideal number of hours of sleep to live a better life

According to a new study, sleeping between 6.4 and 7.8 hours a day slows down biological aging, while both too much and too little sleep accelerate organ and brain damage.

Sleeping is not a simple interlude between two days: it's an active biological repair process that mobilizes the brain and organs. New research published in Nature, conducted by the MULTI Consortium on the basis of UK Biobank data, analyzed half a million people to understand how sleep duration influences biological aging.

Scientists used advanced tools such as MRI (magnetic resonance imaging), protein and metabolic profiles to build true "biological age clocks", capable of measuring how quickly an organ ages in relation to civilian age. The result is a complex snapshot of the human body as an interconnected system.

The key discovery: a U-shaped curve between sleep and aging

The analysis reveals a recurring U-shaped pattern: both insufficient sleep (less than 6 hours) and excessive sleep (more than 8 hours) are associated with faster aging. The optimal point is around 6.4 to 7.8 hours of rest per day.

Within this window, biological clocks indicate a "younger" organism, with benefits observed within various systems: brain, heart, lungs, metabolism and immune system. These data do not indicate a strict cause-and-effect relationship, but a strong association between sleep duration and overall physiological balance.

"Biological clocks" that measure organ age

The research group has developed 23 models of aging clocks based on medical imaging, proteomics (the large-scale study of an organism's proteins) and metabolomics. Each organ, from the liver to the brain, follows a different rhythm of deterioration, which these tools make it possible to quantify with increasing precision.

These clocks reveal that the body does not age uniformly: some tissues may "age faster", others more slowly. Sleep appears to be a transversal factor influencing this internal synchronization, acting simultaneously on several biological levels.

When sleep loses its balance: risks for the whole organism

According to the data analyzed, both too little sleep and prolonged sleep are associated with an increased risk of pathologies such as depression, anxiety, type 2 diabetes, hypertension, cardiovascular disease and respiratory disorders. The digestive system also seems to be affected.

In these two extreme cases, the risk of mortality is significantly higher than average. The researchers hypothesize that very long sleep may also be a sign of underlying disorders, while insufficient sleep may have a direct impact on biological mechanisms linked to stress and inflammation.

A dynamic balance between brain, body and biological time

The study suggests that sleep is not just a brain function, but a coordinated biological network that regulates the whole body. Differences between organs and between individuals indicate that there is no absolute universal rule, but rather an optimal window in which the system functions at its best. Factors such as gender and metabolism slightly influence the ideal duration of rest, but the general principle remains the same: the body seems to "rejuvenate" when sleep stabilizes within a specific interval.

Towards a new approach to sleep-related health

This research opens the way to a more global vision of health, in which regular sleep becomes a central indicator of longevity. It's not just a question of quantity, but of balance. The scientists' final message is clear: sleep is not wasted time, it's one of the body's main levers for controlling its own aging.

Source : Nature