Sleep’s Role in Brain Health

Summary: A new study reveals how sleep duration impacts brain health, specifically relating to stroke and dementia risks.

Analyzing brain images of nearly 40,000 middle-aged participants, the study found that both short and long sleep durations are associated with negative changes in brain structure.

These changes include higher presence and volume of white matter hyperintensities (WMH) and reduced fractional anisotropy, indicators of brain aging and dementia risk. The research underscores sleep as a key factor in maintaining brain health and highlights middle age as a critical period for sleep habit adjustments.

Key Facts:

  1. Inadequate sleep, both too little and too much, is linked to increased WMH presence, larger WMH volume, and lower fractional anisotropy.
  2. These brain changes are associated with higher risks of stroke and dementia.
  3. The study emphasizes the importance of optimal sleep (7–9 hours) for brain health in middle-aged individuals.

Source: Yale

Getting either too much or too little sleep is associated with changes in the brain that have been shown to increase the risk of stroke and dementia later in life, a recent study finds.

The research is published in the Journal of the American Heart Association.

“Conditions like stroke or dementia are the end-stage result of a long process that ends tragically,” says Santiago Clocchiatti-Tuozzo, MD, T32 postdoctoral fellow in the Falcone lab at Yale School of Medicine and first author of the study. “We want to learn how to prevent these processes before they happen.”

This shows a person sleeping.
Long sleep (averaging more than 9 hours per night) was associated with lower fractional anisotropy and with larger WMH volume, but not with risk of WMH presence. Credit: Neuroscience News

In one of the largest neuroimaging studies of its kind to date, the Yale team examined brain images of close to 40,000 healthy, middle-aged participants to evaluate how sleeping habits might impact two measures of brain health: white matter hyperintensities (WMH), which are lesions on the brain indicating brain aging, and fractional anisotropy, which measures the uniformity of water diffusion along nerve axons. More WMH, larger WMH, and lower fractional anisotropy are associated with increased risk of stroke and dementia.

Researchers found that compared with optimal sleep (7–9 hours per night), participants with short sleep had higher risk of WMH presence, larger WMH volume where WMH was present, and lower fractional anisotropy. Long sleep (averaging more than 9 hours per night) was associated with lower fractional anisotropy and with larger WMH volume, but not with risk of WMH presence.

“These findings add to the mounting evidence that sleep is a prime pillar of brain health,” says Clocchiatti-Tuozzo. “It also provides evidence toward helping us understand how sleep and sleep duration can be a modifiable risk factor for brain health later in life.”

Researchers say the study highlights middle age as an important time to adjust our sleeping habits to support brain health.

“Sleep is starting to become a trending topic,” Clocchiatti-Tuozzo says. “We hope this study and others can offer insight into how we can modify sleep in patients to improve brain health in years to come.”

Cyprien Rivier, Daniela Renedo, Victor Torres Lopez, Jacqueline Geer, Brienne Miner, Henry Yaggi, Adam de Havenon, Seyedmedhi Payabvash, Kevin Sheth, Thomas Gill and Guido Falcone were co-authors of the study.

About this sleep and neuroscience research news

Author: Santiago Clocchiatti-Tuozzo
Source: Yale
Contact: Santiago Clocchiatti-Tuozzo – Yale
Image: The image is credited to Neuroscience News

Original Research: Open access.
Suboptimal Sleep Duration Is Associated With Poorer Neuroimaging Brain Health Profiles in Middle‐Aged Individuals Without Stroke or Dementia” by Santiago Clocchiatti-Tuozzo et al. Journal of the American Heart Association


Abstract

Suboptimal Sleep Duration Is Associated With Poorer Neuroimaging Brain Health Profiles in Middle‐Aged Individuals Without Stroke or Dementia

Background

The American Heart Association’s Life’s Simple 7, a public health construct capturing key determinants of cardiovascular health, became the Life’s Essential 8 after the addition of sleep duration. The authors tested the hypothesis that suboptimal sleep duration is associated with poorer neuroimaging brain health profiles in asymptomatic middle‐aged adults.

Methods and Results

The authors conducted a prospective magnetic resonance neuroimaging study in middle‐aged individuals without stroke or dementia enrolled in the UK Biobank. Self‐reported sleep duration was categorized as short (<7 hours), optimal (7–<9 hours), or long (≥9 hours). Evaluated neuroimaging markers included the presence of white matter hyperintensities (WMHs), volume of WMH, and fractional anisotropy, with the latter evaluated as the average of 48 white matter tracts.

Multivariable logistic and linear regression models were used to test for an association between sleep duration and these neuroimaging markers. The authors evaluated 39 771 middle‐aged individuals. Of these, 28 912 (72.7%) had optimal, 8468 (21.3%) had short, and 2391 (6%) had long sleep duration. Compared with optimal sleep, short sleep was associated with higher risk of WMH presence (odds ratio, 1.11 [95% CI, 1.05–1.18]; P<0.001), larger WMH volume (beta=0.06 [95% CI, 0.04–0.08]; P<0.001), and worse fractional anisotropy profiles (beta=−0.04 [95% CI, −0.06 to −0.02]; P=0.001).

Compared with optimal sleep, long sleep duration was associated with larger WMH volume (beta=0.04 [95% CI, 0.01–0.08]; P=0.02) and worse fractional anisotropy profiles (beta=−0.06 [95% CI, −0.1 to −0.02]; P=0.002), but not with WMH presence (P=0.6).

Conclusions

Among middle‐aged adults without stroke or dementia, suboptimal sleep duration is associated with poorer neuroimaging brain health profiles. Because these neuroimaging markers precede stroke and dementia by several years, these findings are consistent with other findings evaluating early interventions to improve this modifiable risk factor.

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  1. I want to understand if this study means consistent episodes of less than and more than 7-9 hours sleep? For example, if one night of the week I had 6 hours sleep but every other night I had between 7-9 hour sleep?

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