The Impact of Poor Sleep on Brain Aging

Recent research has shown that poor sleep may be linked to accelerated brain aging, raising questions about whether unhealthy sleep habits contribute to the development of dementia or are merely early symptoms of the disease. In this article, we review a new study conducted by researchers from the Karolinska Institute on this relationship and its potential causes.

A Comprehensive Study to Understand the Relationship

The study involved 27,500 middle-aged and older adults from the United Kingdom who underwent brain MRI scans. Using machine learning techniques, the researchers estimated the biological age of the brain based on over a thousand brain MRI characteristics.

The study assessed participants’ sleep quality based on five self-reported factors: sleep preference (morning or evening person), sleep duration, insomnia, snoring, and daytime sleepiness. Participants were then divided into three groups: healthy sleep, average sleep, and poor sleep.

Low-Grade Inflammation as a Mediating Factor

The study found that the gap between brain age and chronological age increased by about six months for each one-point decrease in healthy sleep score. People with poor sleep had brains that appeared on average one year older than their actual age.

To understand how poor sleep affects the brain, researchers examined levels of low-grade inflammation in the body. They discovered that inflammation could explain over ten percent of the relationship between poor sleep and brain aging.

Other Potential Mechanisms of the Relationship

The study also explored other potential mechanisms that might explain this relationship, such as the negative impact on the brain’s waste clearance system, which is primarily active during sleep, or the adverse effects of poor sleep on cardiovascular health, which can, in turn, affect the brain.

It is important to note that participants in the UK Biobank study are healthier than the general UK population, which may limit the generalizability of the results. Additionally, the findings rely on self-reported sleep data.

Conclusion

This study provides evidence that poor sleep may contribute to accelerated brain aging, highlighting inflammation as one of the key mechanisms. Since sleep can be altered and improved, it might be possible to prevent accelerated brain aging and potentially even cognitive decline by improving sleep habits. These findings underscore the need for further research to fully understand the relationship between sleep and brain health.