The pandemic aged our brains, whether we got Covid or not, study finds

NBC News

22-07-2025

Brain aging may have sped up during the pandemic, even in people who didn't get sick from Covid, a new study suggests.
Using brain scans from a very large database, British researchers determined that during the pandemic years of 2021 and 2022, people's brains showed signs of aging, including shrinkage, according to the report published in Nature Communications.
People who got infected with the virus also showed deficits in certain cognitive abilities, such as processing speed and mental flexibility.
The aging effect 'was most pronounced in males and those from more socioeconomically deprived backgrounds,' said the study's first author, Ali-Reza Mohammadi-Nejad, a neuroimaging researcher at the University of Nottingham, via email. 'It highlights that brain health is not shaped solely by illness, but also by broader life experiences.'
Overall, the researchers found a 5.5-month acceleration in aging associated with the pandemic. On average, the difference in brain aging between men and women was small, about 2.5 months.
'We don't yet know exactly why, but this fits with other research suggesting that men may be more affected by certain types of stress or health challenges,' Mohammadi-Nejad said.
Brains shrink as people age. When gray matter shrinks prematurely, it can lead to memory loss or judgment problems, although the pandemic study doesn't show whether people with structural changes will eventually develop cognitive deficits.
The study wasn't designed to pinpoint specific causes.
'But it is likely that the cumulative experience of the pandemic—including psychological stress, social isolation, disruptions in daily life, reduced activity and wellness—contributed to the observed changes,' Mohammadi-Nejad said. 'In this sense, the pandemic period itself appears to have left a mark on our brains, even in the absence of infection.'
An earlier study on how teenagers' brains were affected by the pandemic discovered a similar result. The 2024 research from the University of Washington found that boys' brains had aged the equivalent of 1.4 years extra during the pandemic, while girls aged an extra 4.2 years.
In the new study, Mohammadi-Nejad and his team turned to the UK Biobank, a massive database which launched in 2006, to determine whether the pandemic had any impact on people's brains. The database has been keeping track of anonymous health data from 500,000 volunteers who were recruited between 2006 and 2010, when the participants were between 40 to 69 years old. Thus far, the biobank has collected 100,000 whole body scans.
To develop a baseline model of normal aging, to compare with what might have occurred during the pandemic years, the researchers used imaging data from 15,334 healthy individuals that had been collected prior to the pandemic.
'We used this large dataset to teach our model what typical, healthy brain ageing looks like across the adult lifespan,' Mohammadi-Nejad explained.
Next the researchers turned to a group of 996 participants who had two scans, the second taking place on average 2.3 years after the first. Of these participants, 564 had both scans prior to the pandemic, which helped the artificial intelligence learn how the brain changes when there is no pandemic.
The other 432 had a second scan after the start of the pandemic, mostly between 2021 and 2022, allowing the researchers to investigate how the pandemic might have affected brain aging.
Although these second scans were done later in the pandemic, 'they reflect brain changes that likely happened during the height of the pandemic, when people experienced the most disruption,' Mohammadi-Nejad said.
Other research has suggested that environmental factors might cause a person's brain to age prematurely. One study conducted in the Antarctic tied living in relative isolation to brain shrinkage.
'The most intriguing finding in this study is that only those who were infected with SARS-CoV-2 showed any cognitive deficits, despite structural aging,' said Jacqueline Becker, a clinical neuropsychologist and assistant professor of medicine at the Icahn School of Medicine at Mount Sinai. 'This speaks a little to the effects of the virus itself.'
And that may eventually help explain syndromes, such as long Covid and chronic fatigue, she said.
What we don't know from this study is whether the structural brain changes observed in people who didn't get Covid will amount to any observable changes in brain function, Becker said.
Adam Brickman, a professor of neuropsychology at Columbia University Vagelos College of Physicians and Surgeons, said the study is a compelling narrative, but 'still a hypothesis.'
It doesn't show whether the accelerated aging seen in people who didn't get Covid will persist long term, said Brickman, who was not involved with the study.
If the brain indeed was changed by the pandemic in meaningful ways, then people might counter those changes by doing things that are healthy for the brain, he said.
'We know that exercise is good for the brain and keeping blood pressure at a healthy level, for example. We know that sleep and social interactions are important.'