A new study by researchers at Yale School of Medicine (YSM) suggests that sleeping too much or too little can lead to changes in the brain associated with an increased risk of stroke and dementia. In this large neuroimaging study involving nearly 40,000 middle-aged adults, suboptimal sleep duration, defined as less than seven hours or nine or more hours per night, was linked to silent brain injuries known to precede stroke and dementia.
The study used data from the UK Biobank, a database with over half a million participants aged 40 to 69. Participants reported their sleep duration, and nine years later, around 40,000 were selected for a brain MRI study. The researchers evaluated markers of brain health, including white matter hyperintensities and fractional anisotropy, which are associated with increased stroke and dementia risk.
The findings, published in the Journal of the American Heart Association on December 29, highlight the importance of sleep as a key factor in brain health. The relationship between suboptimal sleep and poor brain health persisted even after adjusting for other risk factors like hypertension, diabetes, and smoking.
Santiago Clocchiatti-Tuozzo, MD, a postdoctoral fellow at YSM and the study’s first author, emphasized the need to understand and prevent these processes before they lead to conditions like stroke or dementia. The study suggests that middle age is a crucial time to adjust sleep habits to protect brain health and calls for future clinical trials to explore whether modifying sleep can improve brain health in older age.