Even proper nutrition, quitting bad habits, and an active lifestyle do not always guarantee mental clarity in old age. As the study showed, people who lead a healthy lifestyle may still have an increased risk of dementia — by about 40%.
Many people, even after the age of 70, maintain high mental activity: they continue to socialize, travel, learn new skills, and easily remember information. Their brains remain 'young' and function at a level much earlier than their actual age.
Doctors traditionally recommend a balanced diet, physical activity, positive emotions, and continuous development to maintain cognitive health — all of which contribute to the formation of new neural connections. However, even such efforts may prove insufficient if a person does not get enough sleep regularly or suffers from poor sleep quality.
A study conducted by specialists from the University of California, San Francisco, in collaboration with colleagues from other research centers, showed that the risk of dementia increases if the 'biological age' of the brain exceeds the actual age of the person.
The analysis was based on brain waves — electrical signals that reflect neuronal activity. They are recorded using electroencephalography (EEG) and allow for the assessment of how synchronously different parts of the brain work.
The study utilized a machine learning model that analyzed 13 microstructural characteristics of brain activity. About 7,000 men and women aged 40 to 94, who did not have dementia at the start of the observations, participated in the study. Participants were monitored for 3.5 to 17 years, and approximately a thousand of them subsequently developed the disease.
The researchers studied brain activity during sleep, as this is when processes important for memory and recovery occur. Special attention was paid to delta waves, characteristic of deep sleep, as well as the so-called 'sleep spindles' — short bursts of activity associated with the processing and consolidation of memories.
The results showed that the characteristics of brain waves can determine the 'age' of the brain. In individuals whose brains were biologically about 10 years older, the risk of developing dementia increased by up to 40%.
According to the researchers, many underestimate the importance of sleep for brain health. It is important not only to consider the quantity but also the quality of sleep: frequent awakenings, insomnia, and morning headaches may indicate that the brain is not getting adequate rest and is aging faster.
Experts recommend focusing on prevention: controlling weight, treating sleep apnea if necessary, and monitoring blood pressure levels. These measures help improve sleep quality and contribute to the body's recovery, which directly affects the state of the brain.
