A good night’s sleep could offer more than just a refreshing start to the day. For millions of people living with chronic health conditions, it may also help protect the brain against changes associated with ageing and disease. New research from Karolinska Institutet in Sweden suggests that healthy sleep habits are linked to better memory, thinking abilities and brain structure among people with type 2 diabetes, heart disease or stroke, raising the possibility that improving sleep could help preserve cognitive health.
These three conditions, collectively known as cardiometabolic diseases, are already recognised as major risk factors for cognitive decline and dementia. As populations age and these illnesses become increasingly common, researchers are looking for practical ways to reduce their impact on the brain. Sleep has emerged as a potentially important factor because it influences numerous processes involved in maintaining brain health. The latest study, published in the Journal of the American Heart Association, examined whether healthier sleeping patterns might help lessen the cognitive and structural changes associated with cardiometabolic disease.
To investigate, researchers analysed information from more than 400,000 middle-aged and older adults enrolled in the UK Biobank, including over 54,000 participants with at least one cardiometabolic condition. Brain magnetic resonance imaging (MRI) scans were available for nearly 35,000 participants, allowing the researchers to examine differences in brain structure. Sleep quality was evaluated using five self-reported characteristics: sleep duration, circadian rhythm, insomnia, snoring and daytime sleepiness. Together, these measures provided a broader picture of healthy sleeping habits rather than focusing solely on the number of hours spent asleep.
The findings revealed a consistent association between better sleep and healthier brain outcomes. Among participants with cardiometabolic disease, those reporting healthier sleep patterns performed slightly better on assessments of general cognitive function, problem-solving and information-processing speed than those with poorer sleep. Brain scans also showed that better sleepers had significantly larger overall brain volumes, including greater amounts of grey matter and white matter. These structural differences are particularly relevant because changes in brain tissue can accompany ageing and neurological decline.
Interestingly, the relationship between sleep quality and brain structure was stronger among participants with type 2 diabetes, heart disease or stroke than among those without these conditions. This suggests that healthy sleep may be especially important for individuals already facing elevated risks of cognitive impairment. However, because the findings are observational, they do not establish that better sleep directly prevents brain damage or reverses existing cognitive decline. Other health and lifestyle factors may also contribute to the associations.
“Cardiometabolic diseases are very common in older adults, and they are among the most well-established risk factors for declining cognitive and brain health,” said Abigail Dove, a researcher at Karolinska Institutet’s Aging Research Center. She explained that the findings suggest healthy sleep may help offset some of the adverse effects of these conditions on the brain. Unlike many medical risk factors that can be difficult to modify, sleep habits may offer a relatively accessible opportunity for improvement. The research highlights the potential value of paying greater attention to sleep as part of maintaining long-term brain health.
More information: Yuyang Miao et al, Healthy Sleep Mitigates the Association Between Cardiometabolic Disease and Poorer Cognitive and Brain Health, Journal of the American Heart Association. DOI: 10.1161/JAHA.126.051940
Journal information: Journal of the American Heart Association Provided by Karolinska Institutet