Does the combination of poor sleep and hypertension negatively impact brain health?

This week, we review a retrospective cohort study recently published in the Journal of the American Heart Association by Yiallourou et al., (2024) investigating whether the combined effect of poor sleep and hypertension may negatively impact brain health.

Hypertension, also known as high blood pressure, can lead to cardiovascular diseases such as heart attacks and strokes. Hypertension has been previously shown to impact cerebral vasculature. For example, hypertension can increase the relative risk of cerebral infarcts and cerebral microbleeds.

In a retrospective cohort study recently published in the Journal of the American Heart Association by Yiallourou et al., (2024) investigated whether the combined effect of poor sleep and hypertension may negatively impact brain health. Authors included a total of 682 participants, including 237 participants with hypertension and 445 normotensive participants. Authors investigated the relationship between sleep, cognitive function and brain grey matter volumes using magnetic resonance imaging.

Authors reported that amongst individuals with hypertension, poor sleep was linked with poorer cognitive functioning impacting executive functioning. However, there was no significant association between poor sleep and other measures of cognitive functioning, including overall cognitive function or memory. Whilst a correlation was observed between sleep and executive functioning, the effect size was relatively small and is unlikely to have survived corrections for multiple comparisons. It is also surprising that authors didn’t observe a relationship between sleep and memory given the critical role of sleep in memory consolidation.

Individuals with hypertension showed a significant association between poor sleep and reduced subcortical grey matter atrophy. However, this relationship was not seen amongst individuals without hypertension. These findings suggest that the combination of hypertension and poor sleep may have a cumulative and detrimental impact on brain health. However, no association was found between poor sleep and brain volume for brain regions implicated in cognitive functioning, such as frontal cortical grey matter volume or hippocampal volume.

Since this finding is based on a correlation and no experimental manipulations were used, it is unclear whether a third unexplained factor may be responsible for this relationship, such as an undiagnosed neurological condition, for example. Further research is needed to investigate the mechanisms by which poor sleep and hypertension lead to alterations in brain structure. These findings also highlight the need for further research to investigate the protective effects of sleep on brain health.

Please click here to read the full article: https://www.ahajournals.org/doi/10.1161/JAHA.124.035132#jah310211-fig-0001