brain fog isn't a new thing

covid-19 may have popularized brain fog, but the phenomenon has many connections, including sleep deprivation, chemotherapy and autoimmune diseases.

by karen hawthorne

feb 17 2023

4 minute read

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ever wake up in the morning after a really poor sleep and find it hard to focus on getting dressed or even making coffee? what about that sluggish, confused feeling that sometime accompanies jet lag? even stress can overwhelm our brains, causing us to feel distracted, forgetful and well, foggy.

these are some of the ways to describe the effects of “ brain fog ,” a term made popular by covid-19 with so many people complaining of these symptoms after infection. in fact, it has even been referred to as “ a neurological health crisis.” but it’s not a new phenomenon.

“people who get a concussion talk about brain fog, people who have covid talk about brain fog, people who get chemotherapy talk about brain fog,” explains dr. carmela tartaglia , a cognitive neurologist at the krembil brain institute and co-director of the university health network (uhn) memory clinic at toronto western hospital. she also runs a long covid clinic.

what is brain fog?

if you have brain fog, you’re experiencing some kind of cognitive impairment , whether it has to do with memory, attention or what’s known as “executive function” which oversees tasks like organizing, planning and problem-solving. and while it is linked to sleep deprivation, stress, menopause and covid, a foggy brain can be experienced by people undergoing chemotherapy ( chemo brain ), and can also be a sign of health issues like lupus , multiple sclerosis , chronic fatigue syndrome and lyme disease .

what causes brain fog?

while scientists are unclear as to exactly what is happening in the brain to cause that cloudy-head feeling, some theories posit that inflammation develops in the brain which damages cognitive ability, or that there are misplaced cells that block blood flow to the brain, starving it of the oxygen and nutrients it needs for thinking, memory and information processing.

tartaglia is also unclear as to the exact science behind brain fog. she sees people who contracted covid as early as december 2019 and have lingering symptoms of loss of taste and loss of smell, or cognition challenges that have left them unable to return to work or function as before.

“most of my patients have made it back to work,” she says. “but there are a few stragglers who, for some reason, are quite disabled. it’s not clear why, because it’s not like we find anything.”

and it’s this absence of clues that is both baffling and worrying.

adopting lifestyle tweaks is a good first step towards bettering your cognitive function. getty

cause of brain fog remains elusive

while some viruses, like the herpes simplex virus , or serious bacterial infections like listeria, invade the brain and can be detected, covid works differently. one hypothesis is that there’s an indirect effect on the brain through inflammation where your immune system attacks your body’s own tissues and organs. this happens in lupus , for example, an autoimmune condition that’s associated with high levels of inflammatory markers and cognitive impairment.

“your body’s response to a virus is to gear up your immune system and say, ‘ok, it’s a war, and this is my army,’” tartaglia explains. “the inflammatory markers are my army and they’re going to fight this virus, but that army can cause damage, just like war causes damage. so that inflammation could also exert a negative effect and give people trouble.”

despite how little we know about brain fog specifically, we do know that there is little that doesn’t impact the brain and how it functions. tartaglia points to a long list of lifestyle habits and other factors that can take a toll on your brain, including not getting enough sleep which will slow cognitive ability as the brain copes with the deficit. pain, depression and anxiety will have a similar impact, as will a poor diet and a lack of physical activity.

“you have to realize your brain has this limited bandwidth,” she says.

help for brain fog lies in lifestyle changes

there is no quick fix for a head filled with fog, but adopting lifestyle tweaks is a good first step.

“i prescribe exercise for everybody,” tartaglia says, noting how important regular exercise is to cognition and overall health. “the way i treat my patients is to try to optimize their system. we’ll make sure your mood is well-controlled. we’ll assess your sleep to see if you have sleep apnea or some other sleep problem, we’ll make sure you start exercising. if people have mood problems, like low mood or anxiety, we suggest cognitive behavioural therapy (cbt) because it has good evidence for treating depression and anxiety.”

if cognitive dysfunction is affecting memory, concentration and completing tasks, she recommends occupational therapy to help build strategies into routines, like putting errands in an agenda and setting up alarms as reminders to take medications, for example.

avoiding alcohol and getting enough sleep can also have a beneficial impact on clarity, alertness and overall better brain health.

karen hawthorne is a toronto-based writer.

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karen hawthorne

karen hawthorne worked for six years as a digital editor for the national post, contributing articles on health, business, culture and travel for affiliated newspapers across canada. she now writes from her home office in toronto as a freelancer, and takes breaks to bounce with her son on the backyard trampoline and walk bingo, her bull terrier.

brain fog isn't a new thing