Poor sleep quality accelerates brain aging

While the link It has long been known that there is a link between poor sleep and dementia, and it has not been clear whether poor sleep habits can cause dementia or whether poor sleep is an early symptom of dementia. but, New search And I revealed it He sleeps Quality may have a direct impact on the rate at which Brain age.

“Our findings provide evidence that poor sleep may contribute to accelerated brain aging.” He explains Abigail Dove, a neuroepidemiologist at the Karolinska Institute in Sweden, “points to inflammation as one of the underlying mechanisms.”

High correlation with night owl lifestyle and snoring

The researchers assessed their sleep quality across five dimensions in 27,500 middle-aged and older people (mean age 54.7 years) enrolled in the UK Biobank (a research institute that conducts long-term follow-up studies of the effects of genetic predisposition and lifestyle on disease). About nine years later, they scanned the participants’ brains with MRIs and used machine learning models to estimate their biological brain age.

The researchers measured sleep quality based on chronotype (morning or evening), sleep duration, presence or absence of insomnia, presence or absence of snoring, and daytime sleepiness. Using this data, they classified participants into three sleep styles, finding that 41.2% had healthy sleep, 3.3% had poor sleep, and 55.6% fell into the intermediate group.

The analysis showed that for every decrease in healthy sleep score, the difference between brain age and chronological age increased by about six months. The group with the lowest sleep quality showed that their brains were about one year older than their chronological age. This suggests that differences in sleep duration and sleep habits can significantly affect the rate at which the brain ages.

Researchers have found that a nocturnal lifestyle, unhealthy sleep duration (more than 7-8 hours), and snoring habits are particularly strongly associated with brain aging. They also found that the five factors that determine sleep quality interact with each other. For example, insomnia can lead to excessive daytime sleepiness, and a nocturnal lifestyle can lead to shorter sleep periods.

Lack of sleep leads to chronic inflammation in the body

To understand the mechanism by which lack of sleep affects the brain, the research team also measured the level of low-grade inflammation in the body. Specifically, they used a set of biomarkers, such as C-reactive protein levels, white blood cell and platelet counts, and the ratio of granulocytes to lymphocytes (a type of white blood cell), to analyze the role of inflammation in the relationship between sleep patterns and brain aging.

The results confirmed that high levels of inflammation in the body tend to increase the age of the brain. Mediation analysis (a method of analyzing the effect of mediating variables in a causal relationship between two variables) found that inflammation explains nearly 7 percent of the association between average sleep patterns and brain aging, and more than 10 percent of the association with poor sleep patterns. In other words, poor sleep quality is very likely to facilitate chronic inflammation in the body, which in turn accelerates brain aging.

In addition to inflammation, there are several other ways that lack of sleep can negatively affect the brain. One is through its negative effect on the glymphatic system, which primarily removes waste from the brain during sleep. If toxic substances in the brain are not removed efficiently during sleep, this can impair the function of neurons in the long term. The researchers also noted that lack of sleep can worsen cardiovascular health, indirectly harming blood flow and tissue in the brain.

This story originally appeared on WIRED Japan and was translated from Japanese.