Memory loss, confusion, dizziness and delirium are among the effects of long-term COVID on the brain. But even people without a positive diagnosis feel the weight of the pandemic — stress hormones flood the brain, deteriorating the ability to solve problems, stay focused, and sleep.
“When we have a brief stress, if we're dealing with a deadline, for example, or planning for, say, a wedding or an event, that's okay. … The problem arises when you have very prolonged levels of stress. … Whenever we're stressed, we release a hormone … called cortisol. And that hormone … binds to receptors on brain cells, preventing them from doing their job appropriately,” explains Michael Yassa, director of UC Irvine Center for the Neurobiology of Learning and Memory. “And the longer that we're in that stress state, the longer that the brain is in this compromised or problematic state.”
He explains further that brain cells differ from the body’s other cells in that they are constantly communicating with each other, and those connections are called synapses. Neurochemicals like dopamine and adrenaline are exchanged at those interfaces.
“What happens when you have cortisol onboard is you compromise the cell's ability to effectively communicate with the next cell. … You get an isolation of brain systems where they can't really coordinate their actions, and can’t support our day to day mental functions.”
Monotony and brain fog
The lack of stimuli can be stressful too.Yassa says the traditional wisdom is that kids' brains are more resilient because of their high plasticity. That’s especially problematic when we get older.
“When you deprive individuals who may already be at risk for things like Alzheimer's/dementia from social exchanges, we can see faster deterioration. So I think the effects on older adults, for example, would be disproportionate to those who are in middle adulthood or young adulthood.”
The stress induced by monotony can worsen brain fog, disturbing a neural network he likens to to trees.
“With what we call brain fog … the connections brain cells make with each other are like trees and tree branches. If you look at trees that are adjacent to each other, and their tree branches might be interlocking with one another, that's really what that's like, because these branches, what we call dendrites, are where the connections are made. And what we see is that these branches start to now pull away from each other. … That happens throughout the brain. So you can expect a very broad level of impairments across multiple systems.”
When stress is removed, he says the brain can rebuild those connections. “We can say it's reversible, this brain fog, like it's gonna go away at some point. But I think we have to work at it. Also, we have to make sure that we're living a healthy active lifestyle.”
But that’s if the brain was healthy to begin with. When it has comorbidities — other conditions that compromise function — then people will have more difficulty recovering, or their recovery may be nearly impossible.
Kids’ brains: Strong but impressionable
Yassa says the traditional wisdom is that kids' brains are more resilient because of their high plasticity. However, new research says this is not only a time of massive growth but also vulnerability.
“Some of my colleagues here at UC Irvine, for example, have demonstrated recently that unpredictable and chaotic early life environments do lead to this rewiring of brain networks … in a way that is long-lasting and can impact the brain much later in adolescence and then adulthood, and can make it so that brains are much more vulnerable to conditions like post-traumatic stress disorder, and anxiety, anhedonia, depression, and so on.”
He notes that childhood experiences of trauma, negligence, and abuse have long-lasting effects too and are tough to undo.
“You really have to develop strategies later in life to be resilient to them and to deal with them effectively. But you have to grow new synapses. … You can’t just eliminate the impacts.”
Mitigating stress through exercise, sleep and diet
Yassa says people must create a healthier lifestyle that involves regular exercise, good quantity and quality of sleep, a regular and predictable daily schedule, mindfulness, meditation, yoga or a nature walk.
“Chief among them, I would say sleep and exercise would be the top two. If we can master those … then we're really doing like 90% of what we need to do."
He recommends 30 to 60 minutes of physical activity daily, at least at the level of walking, and seven to eight hours of sleep, though some people can function with less.
When it comes to food and drink, anything that’s bad for your heart will be bad for your brain, and caffeine and alcohol should be kept in moderation, he notes.