In answer to my questions, Sexton elaborated on some of her latest scientific findings, shared her thoughts on the next frontier for sleep and brain studies and offered some tips on how to improve the quality of our sleep.
Describe your research on poor sleep and declining brain volume.
Poor sleep quality, which can include difficulties falling asleep, waking up during the night or waking up too early, has previously been linked to reduced brain volume by clinical studies of insomnia. In a study published in the journal Neurology, we used magnetic resonance imaging (MRI) to examine if sleep problems were linked to declining brain volume in a sample of 147 community-dwelling adults aged between 20 and 84 years. We found that poor sleep quality was associated with an increased rate of decline in brain volume over three to five years.
What impact does lack of sleep have on an aging brain, and how early can the effects be seen?
Sleep problems affect up to half of older adults and are associated with an increased risk for dementia. We found that the links between sleep problems and decline in brain volume were particularly strong in adults over the age of 60 years.
We are just beginning to discover the vast implications poor sleep has on the brain. What are the trends in research right now? What are scientists most eager to learn more about?
A key outstanding question regards whether poor sleep quality is a cause or an effect of changes in brain structure, or if the relationship is bidirectional. On the one hand, it has been proposed that sleep is the brain’s “housekeeper,” serving to restore and repair the brain. It follows that if sleep is disrupted, then processes that help restore and repair the brain are interrupted and may be less effective, leading to greater rates of decline in brain volume. On the other hand, it may be that greater rates of decline in brain volume make it more difficult for a person to get a good night’s sleep.
There are a number of studies that could be performed to help us understand whether poor sleep quality is a cause or a consequence of changes in brain structure. For example, in future studies we would like to investigate whether improving sleep — for example, through cognitive behavioral therapy — can help slow decline in brain volume. If improving sleep is shown to slow the rate of decline in brain volume, this would indicate that sleep is directly beneficial to the brain and potentially an important way to improve brain health.
How do you advise people to improve their sleep?
Commonly advocated tips for good sleep hygiene include avoiding caffeine and alcohol close to bedtime, exercising during the day and establishing a regular nighttime routine. If sleep problems persist, I would advise people to visit their doctor, who may recommend a course of cognitive behavioral therapy for insomnia or a pharmacological treatment.