Human brain looks years 'older' after just one night without sleep, small study shows

According to a research, even one night without sleep can cause structural changes in the brain that are comparable to those that occur as people age.

A recent research indicates that even one night without sleep can make the brain appear older, as if it had matured one to two years over night.

After a restful night's sleep, these alterations, however, seem to vanish.

In the study, researchers used machine learning to determine the "brain age" of participants' brains using magnetic resonance imaging (MRI) images taken before and after they had a complete night of slumber. According to research findings that were released on February 20 in the Journal of Neuroscience, one night of total sleep deprivation causes brain alterations that are comparable to those that occur after one or two years of aging.

According to Judith Carroll, an assistant professor of psychiatry and biobehavioral sciences at the University of California, Los Angeles who was not engaged in the research, brain age is "a very fascinating metric in terms of looking at how that alters from the sleep loss."

A total of 134 participants were divided into four groups for the purposes of the study: total sleep deprivation (no sleep for one night), partial sleep deprivation (three hours in bed for one night), chronic sleep deprivation (five hours in bed each night for five nights), and a control group. The data were taken from five existing data sets (eight hours in bed each night). Prior to sleep restriction, each group had at least one night of baseline sleep during which they slept for eight hours; most groups also experienced a complete night of recovery sleep.

In order to evaluate how people's brains appeared before and after sleep deprivation and after a complete night of rest, each person had an MRI obtained after each night.

Using a machine-learning algorithm dubbed brainageR that was trained on data from more than 3,000 individuals, the researchers were able to calculate the apparent ages of the subjects' brains. The freely accessible program uses a person's brain MRIs to estimate their chronological age based on the tissue and fluid volume of healthy brains at various ages. Researchers discovered that brainageR could correctly estimate age within about four years in previous experiments.

In their latest study, the researchers discovered that brainageR assessed the participants in the group who slept poorly for one night to be, on average, one to two years older than initial predictions. These variations disappeared after a night of rest.

In terms of age forecasts, there were no appreciable variations between the partial and chronic sleep loss groups and the control group.

These findings are consistent with previous studies on how sleep loss affects the brain. The distribution of fluid and the amount of gray matter in the brains of sleep deprived individuals have been shown to alter, among other things.

According to study senior author Dr. David Elmenhorst, a professor in the Department of Neuroscience and Medicine at the German research center Forschungszentrum J├╝lich, this "widespread shift in brain morphology... would be caught with this technique of brain age as well." Importantly, he described the findings as changes that the machine-learning system mistook for aging rather than real aging.

Carroll said that it is difficult to interpret the study's findings because this impact was only observed in the group who had experienced complete sleep deprivation. Even the chronic condition lasts only five days, so I'm not convinced we can say anything about the long-term consequences of chronic sleep loss, she said.

The research also had a limited sample size. A bigger sample size, according to Elmenhorst, might emphasize less significant impacts in the other groups, such as a few-month increase in brain age. Carroll suggested that future studies include participants who regularly lack sleep, such as those who work shifts.

When they are awake all night, "a lot of people really battle to slumber [during the day]," she said. "I believe it could be really useful and more informative to do something that looks at this in more detail in those groups."