If you've struggled to think clearly during the coronavirus pandemic, you could be experiencing "brain fog" – and one neuroscientist has explained how to beat it.
"Brain fog is a collection of symptoms which give rise to loss of mental clarity or foggy thinking," Sabina Brennan wrote in her recently published book "Beating brain fog."
While there are no statistics on the prevalence of brain fog specifically, Brennan highlighted that around 600 million people worldwide suffer from cognitive dysfunction, which she said is a clinical description of this issue.
Difficulty thinking clearly has also been noted as one of the debilitating symptoms of "long Covid." But even if you haven't had the coronavirus this past year, Brennan told CNBC you might still have experienced brain fog and outlined some ways to overcome it.
According to Brennan, one of the main reasons people experience brain fog is because of a lack of routine.
Prior to the pandemic, Brennan said that around 40% of our behaviors were habitual, and this is "essential in order for our brain to function effectively."
This is because the brain relies on patterns.
Speaking to CNBC via video call, Brennan explained that the brain is a high-energy organ, using around a quarter of the nutrients we consume. The cerebral cortex, known as the "thinking part of the brain," is biggest consumer of energy.
In order to process this energy efficiently, the brain is constantly scanning for patterns.
This is so it can carry out "automated behavior using far less resources," she said. The thinking part of the brain is really only engaged at the beginning and end of an activity, "like a bookend," with the emotional, or limbic, section of the brain taking care of the rest.
"By definition, it's effortless, it's autopilot. You hear a lot about people saying we spend too much time on autopilot — that may be true — but we must spend some time on autopilot, otherwise our brain is overwhelmed completely," Brennan said.
Much of our morning routine prior to the pandemic was habitual, Brennan said. So you might not have your "first conscious engagement stress on your brain until maybe 9:30 a.m.," when you arrived at the office.
The spread of Covid and subsequent lockdowns disturbed much of that routine, she said, as most people started to work from home. This presented a number of challenges, such as finding somewhere suitable to work, motivating yourself to get dressed and going to bed at a reasonable time.
As such, Brennan said it was common for behavior to became quite "erratic" during this time, making it hard for the brain to identify a pattern.
"Your brain is really overwhelmed by that, so there's very little left to do the really cognitive stuff," she said.
A key first step to overcoming brain fog is to reintroduce routine, Brennan said, suggesting that people even create a "fake commute" like a walk around the block to "bookend the day."
Brennan stressed that brain fog was not a "diagnosis, disease or a disorder," but instead a sign of something underlying such a health problem or the consequence of lifestyle choices — such as lack of sleep.
In fact, she said getting enough sleep was crucial in combatting brain fog, as it allows time for the brain to clean out toxins.
She said that it's comparable to "having the streets cleaned at nighttime when there's no traffic on them."
"That's essentially what the brain really needs, is you not to be engaged in cognitive activity so that it can do a really deep clean and clear out those toxins," she added.
One simple way to tell if you're not getting enough sleep, Brennan said, is if you wake up feeling groggy. This is sign that the sleep chemical adenosine, which makes us drowsy, has not fully cleared out of the body and that you're in "sleep debt," she explained.
In addition, Brennan said that exercise was crucial to dealing with brain fog, as it releases a protein called brain-derived neurotrophic factor. It acts like a "fertilizer," which makes it easier for brain cells and connections to grow.