PLOS: Any Deviation from Sleep Norms Increases Dementia Risk

A sleep duration of seven to eight hours per day is associated with the lowest risk of developing dementia, while both a lack and an excess of sleep increase the likelihood of the disease. This was revealed by a study published in the journal PLOS ONE.

Researchers synthesized the results of 69 scientific papers involving 4.5 million people and evaluated the impact of three lifestyle factors: sleep duration, physical activity levels, and sedentary time. The analysis showed that sleep specifically within the range of seven to eight hours is linked to the minimum risk of dementia.

Deviations from this norm increased the probability of the disease. For instance, sleeping less than seven hours was associated with an approximately 18% increase in risk, while sleeping more than eight hours was linked to a 28% increase. Scientists also note that excessive sleep may be just as unfavorable a factor as sleep deprivation.

Additionally, the study found that a sedentary lifestyle plays a significant role. People who spend more than eight hours a day in a seated position, and those who dedicate less than 150 minutes per week to physical activity, are more likely to face dementia.

The authors emphasize that the identified correlations do not prove a direct cause-and-effect relationship. For example, increased sleepiness might not be a risk factor but rather an early sign of developing neurodegenerative diseases, including Alzheimer's.

Nevertheless, the body of data points to the importance of lifestyle for brain health. Regular physical activity, limiting sedentary time, and getting quality sleep can contribute to improved blood circulation, reduced inflammation, and more effective "cleansing" of metabolic waste from the brain.

Since no effective cure for dementia currently exists, scientists view behavioral changes as one of the key methods for prevention. According to their estimates, up to half of all cases could potentially be prevented through lifestyle adjustments.

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