Sleeping Late Every Night? Study Says Poor Sleep Makes Your Brain Age Faster

As you age, your cognitive functions also weaken. This ageing affects memory, focus and problem-solving skills. While this ageing happens naturally with your biological age, sometimes improper lifestyle habits make your brain age faster, raising serious concerns for brain health and the potential of developing dementia in the long run.

A study published in eBioMedicine, part of The Lancet Discovery Science, on September 30, 2025, identified poor sleep as one of the reasons for premature brain ageing.

How poor sleep harms your brain

Often, people check their phones late at night, delaying sleep, which is terrible for brain health. (Picture credit: Freepik) — Often, people check their phones late at night, delaying sleep, which is terrible for brain health.

The study revealed that sleep offers protective benefits for your brain. Those who don’t sleep well or enough may be at risk of a prematurely aged brain, faster than the rest of their bodies. Sleep disturbances set the path for neurogenerative diseases in future because of accelerated ageing.

The researchers examined over 27,000 adults and used brain scans to estimate brain age. This is a measure of how old the brain appears compared to a person’s actual age. Those who have intermediate or poor sleep patterns had a much older brain than their chronological age. People with intermediate sleep patterns had brains that were 0.6 years older, while those who slept poorly had over a year older than their biological age.

The study researchers developed a sleep score, and every drop in that score resulted in increased brain age by about a half a year.

Cause behind brain ageing

The researchers identified chronic inflammation to be one of the reasons for this premature brain age. About 10 per cent of the link between poor sleep and brain ageing comes back to chronic inflammation, which affects the brain cells, i.e., neurons. Much of sleep’s importance resides in its ability to make the body recover. Insufficient sleep causes the body’s inflammation levels to rise, and when for prolonged duration one is sleep deprived, the inflamed state of the body affects the neurons too, leading to faster brain ageing from damaged brain cells. This is why quality sleep and following a regular sleep routine help to make a big difference in keeping your brain younger.