Bad Sleep Habits in Midlife Can Lower Brain Volume and Worsen Cognitive Health, Study Finds

Sleep deprivation is something many of us experience in our lives, with an estimated 50 to 70 million Americans dealing with the issue at any given time. This lack of sleep is especially prevalent during mid-adulthood, which may be even more concerning, in light of a new study.

Researchers at The Australian National University recently examined sleep habits and their impact on the brains of middle-aged adults. The findings, published in the journal Scientific Reports, show that even at this younger age, cognitive health and brain volume can be negatively impacted by poor sleep habits.


Lead author Dr. Tergel Namsrai says, “The mechanisms underlying the link between sleep and brain health are not well understood – there’s a lot of work to be done. But our study shows it could be an important target if we want to improve brain health into old age and delay the onset of dementia.”

The team’s research involved more than 29,000 people from the longterm UK Biobank study. The participants, with an average age of 54, had imaging visits with sleep measures and brain scans taken, with half also having cognitive health measured.

The researchers found that a variety of sleep habits were linked with poor brain health. Those who slept for fewer than six hours per day had lower brain volumes and worse memory, reaction time, and fluid intelligence. This was also true for those who slept more than nine hours. Similar results were also found for people who slept during the day. They exhibited lower brain volumes, as well as worse reaction time and fluid intelligence.


Though more research is needed, the team says their results show that getting quality sleep may be another thing we can do to protect our cognitive health, along with other established steps we can take.

Dr. Namsrai explains, “Around 20 to 40 per cent of dementia cases are attributable to modifiable, non-genetic factors. The most well-known of these include smoking, alcohol misuse and obesity. But sleep is an emerging risk factor.”

This current research mirrors the findings of other studies, including one that found getting too much or too little sleep may increase Alzheimer’s risk. For more background on sleep and dementia risk, click here.

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