Research from Stockholm University (Sweden), published in the scientific journal ‘Proceedings of the Royal Society B’, has revealed that being sleepy can make a person feel ten years older, which is why the authors recommend protecting sleep to feel younger.

In this sense, experts assure that feeling young is not just a matter of perception, it is actually related to objective health results. Previous studies have shown that feeling younger than your actual age is associated with a longer, healthier life. Subjective age has even been shown to predict actual brain age, with those who feel younger having younger brains.

“Since sleep is essential for brain function and general well-being, we decided to see if sleep holds any secrets to preserving the feeling of youth,” said Leonie Balter, a researcher at the Department of Psychology at Stockholm University.

In the first study, 429 people aged 18 to 70 were asked how old they felt, how many days in the previous month they had not gotten enough sleep, and how sleepy they were. It turned out that for every night of insufficient sleep in the last month, participants felt on average 0.23 years older.

In a second study, researchers tested whether lack of sleep was indeed the cause of participants feeling older. To do this, they carried out an experimental sleep restriction study in which 186 people between 18 and 46 years old participated. The participants restricted their sleep for two nights—just four hours in bed each night—and on another occasion got enough sleep for two nights, with nine hours in bed each night.

After sleep restriction, participants felt on average 4.4 years older than when they had had sufficient sleep. The effects of sleep on subjective age seemed to be related to how sleepy they felt. Feeling extremely alert was related to feeling 4 years younger than your actual age, while extreme sleepiness was related to feeling 6 years older than your actual age.

“This means that going from feeling alert to sleepy added an astonishing 10 years to how old you felt,” says Leonie Balter, stating that the implications for daily life are clear.

“Protecting our sleep is crucial to maintaining a feeling of youth. This, in turn, can promote a more active lifestyle and encourage health-promoting behaviors, as both feeling young and alert are important to our motivation to be active.” “concludes the researcher.