People with type 2 diabetes, heart disease or stroke who sleep well have better cognitive function and greater brain volume than people with the same conditions who sleep poorly, according to a new study from Karolinska Institutet. The researchers believe that good sleep may help to counteract the negative effects on the brain associated with these conditions.
Type 2 diabetes, heart disease and stroke – collectively referred to as cardiometabolic diseases – are linked to an increased risk of cognitive decline and dementia. Researchers have now investigated whether healthy sleep can mitigate these associations. The results are presented in the Journal of the American Heart Association .
The study is based on data from over 400,000 middle-aged and older people in the UK Biobank, of whom just over 54,000 had at least one cardiometabolic disease. MRI (magnetic resonance imaging) scans of the brain were also available for nearly 35,000 of the study participants. Sleep was assessed based on five self-reported factors: sleep duration, circadian rhythm, insomnia, snoring and daytime sleepiness.
Performed better on tests
People with cardiometabolic disease who slept well performed slightly better on tests of general cognition, problem-solving ability and processing speed than those with the same conditions who slept poorly. They also had significantly larger total brain volume, as well as greater volumes of grey and white matter. The link between sleep and brain structure was more pronounced in people with type 2 diabetes, heart disease or stroke than in those without these conditions.
“Cardiometabolic diseases are very common in older adults, and they are among the most well-established risk factors for declining cognitive and brain health,” says Abigail Dove, researcher at the Aging Research Center, Department of Neurobiology, Care Sciences and Society at Karolinska Institutet. “Our findings suggest that healthy sleep may help offset some of the adverse consequences of cardiometabolic disease for the brain. This is meaningful because for most people, improving sleep is an accessible and achievable goal.”
The study was funded by Karolinska Institutet’s strategic research programme in diabetes, the Alzheimer’s Foundation, the Swedish Research Council for Health, Working Life and Welfare, the Swedish Society for Medical Research, and the Dementia Foundation, among others. The researchers declare no conflicts of interest.
Publication: “Healthy sleep mitigates the association between cardiometabolic disease and poorer cognitive and brain health” , Yuyang Miao, Livia Fingerson, Elise Walters, Kathryn DaSilva, Mariam Militonyan, Aleksandra Koycheva, Sakura Sakakibara, Charlotte Sørensen, Shireen Sindi, Abigail Dove, Journal of the American Heart Association, online 4 November 2026, doi: 10.1161/JAHA.126.051940.
Journal of the American Heart Association
Observational study
People
Healthy sleep mitigates the association between cardiometabolic disease and poorer cognitive and brain health
4-Nov-2026