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Why Do We Get Brain Fog? · So That's Why

0:04
Jen Oliver: Welcome to the, so that's Why podcast, where we unpack the
0:07
science behind everyday questions.
0:09
I'm Jen.
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Chris Smith: I'm Chris.
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Matt Edmundson: And I'm Matt.
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Jen Oliver: So today we're talking about something most of us experience,
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but rarely discuss in depth.
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Brain fog.
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You know that feeling when you're staring at your screen, rereading the
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same sentence for the fifth time and your brain just isn't cooperating?
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Matt Edmundson: Oh, you mean like, you know, when your mind feels like
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it's wrapped in clinging film, which is, you know, most of the time,
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isn't it, when you walk into a room?
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I started doing this more and more.
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I I thought this was an age thing where you just forget the reason
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why you went into the room.
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Jen Oliver: Exactly.
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And here's what's fascinating.
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Brain fog isn't actually a medical diagnosis.
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It's an umbrella term for a whole collection of cognitive symptoms that
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signals something that's not quite right with how your brain is functioning.
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Chris Smith: It is, and the reason it's so important to talk
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about is it's incredibly common.
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And so studies have shown that over a quarter of us report experiencing
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brain fog at different times,
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Matt Edmundson: which is good news, right?
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Uh, I good news, it means I'm not alone, uh, in my brain, you know, when my brain
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occasionally decides to go on strike,
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Jen Oliver: not at all.
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And the symptoms are pretty consistent.
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Difficulty concentrating, forgetfulness, sluggish thinking, and mental fatigue.
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It's not dementia.
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More like your brain temporarily.
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Switching gears to conserve energy.
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Chris Smith: And what I want to explore today is why your brain's immune cells can
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get stuck in this kind of always on mode and why hormonal changes can fundamentally
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al alter how your brain operates.
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Matt Edmundson: So brain fog then isn't just about being tired or stressed.
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Jen Oliver: Definitely not.
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There's.
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Real biological mechanisms at play.
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First off, your brain is a huge energy consumer.
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It's about 3% of your body weight, but it uses 20 to 25% of your body's energy.
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Matt Edmundson: And when you put it like that, then Jesus, no wonder my brain
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struggles when it's under pressure, if it's using all of that energy.
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Chris Smith: Absolutely.
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And one major factor here is so-called neuroinflammation.
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That's when your brain's immune cells get activated.
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Now, normally this is a protective thing, but if it persists, it can
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slow down your cognitive function.
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Matt Edmundson: So what keeps these immune cells activated then?
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Jen Oliver: So there's lots of things, um, like infections, chronic
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stress, poor sleep, toxin exposure.
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The problem occurs when these immune cells, they're called
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microglia, stay activated long after the initial threat has gone.
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So they keep releasing inflammatory molecules called cytokines.
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Which then disrupt your normal brain signaling,
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Chris Smith: and it's a really interesting thing.
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So it's something that researchers have studied closely during COVID, and
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particularly what we know is long COVID.
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So studies have shown that using well studies, using brain
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imaging, found that patients with.
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Post COVID brain fog show widespread microglia activation, so their
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brains immune cells are basically still in this emergency mode.
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Months after the infection it was trying to get rid of already cleared,
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Matt Edmundson: which sounds pretty exhausting for the brain, right?
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Jen Oliver: It is.
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And the degree of inflammation directly correlates with symptom severity.
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So the more inflamed the brain tissue, the worse the cognitive symptoms.
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And those cytokines we mentioned before, they impair memory,
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attention, and mental clarity.
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Chris Smith: And this is also linked with what we call the blood brain barrier.
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So this is the membrane that controls what enters your brain from your bloodstream,
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but importantly, what doesn't as well.
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Matt Edmundson: So this membrane then is like a security gate, if I can put
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it in simple terms, which I need, um, protecting my brain from random stuff
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to sort of floating around in my blood
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Jen Oliver: exactly that it keeps harmful substances out while
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allowing essential nutrients through.
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Chris Smith: And this connection comes because, um, a study in 2024 found that in
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long COVID patients with brain fog, this blood-brain barrier becomes compromised.
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So it's basically leaky that security gate's a little bit open, as it were,
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Jen Oliver: and that the impact of a leaky blood brain barrier, open
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security gate is pretty frightening.
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You know, it's frightening.
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The inflammatory molecules and cells that should never get into the brain
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tissue, start getting in and then that triggers more inflammation and disrupts
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the normal processes in the brain.
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Well, okay.
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Matt Edmundson: Putting this back in simple man's terms for me.
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Um, so like you say, the security gate isn't just a jar, it's actually
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letting things through some suspicious characters, uh, if you like, that
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should not actually be getting in.
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Jen Oliver: Yeah, that's actually not far off.
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And the barrier disruption.
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It was evident in these lung COVID patients with brain fog, but not in
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those without cognitive symptoms.
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So the leakiness was most notable in the temporal lobes and the
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frontal cortex regions, which are crucial for memory and attention.
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Chris Smith: And, um, another important factor with the brain
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here is cerebral blood flow.
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So your brain needs a constant delivery of oxygen and glucose through its blood.
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But that supply is reduced or disruptive even temporarily that will,
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um, affect cognitive performance, which will drop almost immediately.
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Matt Edmundson: So it's a bit then like a, a power cut affecting my computer.
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Jen Oliver: Yeah.
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Similar concept.
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So some long COVID patients with brain fog show measurably
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reduced cerebral blood flow.
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Um, and this can have an added impact to people suffering conditions like.
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Postal tachycardia syndrome where brain fog worsens when you stand upright
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Chris Smith: and moving around with the biology.
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Um, the mitochondria also come into play here.
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Now you might remember these from your secondary school
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biology, or you might not.
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Matt Edmundson: Yeah, I don't.
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Jen Oliver: I do.
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Chris Smith: So yeah, the mitochondria for mass benefit, they are basically what,
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let's call them little tiny power stations that are inside every cell in your body.
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Uh, so, but with your brain's huge energy consumption, any impairment to
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these kind of little cellular batteries massively affects cognitive performance.
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Matt Edmundson: So what causes, and thank you for, you know, simplifying
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for me, um, what causes these power stations then to malfunction.
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Jen Oliver: So multiple factors can do that.
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Things like aging, chronic stress, stress caused by pollutants in the environment.
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Nutritional deficiencies, lack of physical activity or exercise.
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Matt Edmundson: It's always in there, isn't it?
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Jen Oliver: It's always in there.
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It's always in there.
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And when the mitochondria aren't functioning properly, all the
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cellular and neural signaling, it becomes less efficient.
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It doesn't work as well.
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Chris Smith: Yeah, the worst thing is it's a massive vicious cycle, so inflammation
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damages the blood-brain barrier.
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Blood bla brain barrier damage.
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Matt Edmundson: That's not easy to say.
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Jen Oliver: No, it's a tongue twister.
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Chris Smith: The BBB damage here allows more inflammatory molecules
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in inflammation impairs mitochondrial function and this is affecting the body's
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overall ability to function efficiently and round and round and round it goes.
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Matt Edmundson: Yeah, I bb, I like that.
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So what actually triggers these changes in the first place then?
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And what would you guys say is the most important factor?
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Jen Oliver: Sleep.
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It all comes down to sleep.
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Sleep has got to be the most crucial factor, and we know that from research
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that just after one night without sleep, your reaction time slows by 50%.
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Your work in memory drops by 40% and your ability to form new memories
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decreases by nearly 40% as well.
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Chris Smith: Yeah, totally.
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So during sleep, your brain goes into this kind of maintenance mode.
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Um, but during that, that phase, it's flushing out waste.
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But that includes proteins that can contribute to diseases like
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even including Alzheimer's.
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Matt Edmundson: So pulling an all-nighter to finish a project essential essentially
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cancels the brain's rubbish collection.
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And actually this reminds me of what we talked about when
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we talked about sleep, right?
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In a previous episode.
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How the brain takes out the trash while you sleep.
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Jen Oliver: Yeah, exactly.
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And the effects persist.
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So studies show brain function doesn't normally return until about 72 hours.
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72 hours after sleep deprivation.
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And sleep plus dis disrupts communication between your cells
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and your neurons in your brain.
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Chris Smith: Yeah, definitely.
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And the other thing is chronic stress.
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'cause it's a big player in brain fog.
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So, and this is mostly because of cortisol, which is your
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body's main stress hormone.
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So when cortisol stays high for too long, it can affect the hippocampus part of
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the brain, which is essential for memory.
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Matt Edmundson: Yeah.
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And it makes sense that stress ha can harm the brain, but how
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does, how does it do that exactly?
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Jen Oliver: So the hippocampus has got lots of cortisol receptors, which
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make it really sensitive and too much cortisol over time can shrink it a bit.
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And then that the effect of that is that it slows the creation of new neurons
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and it weakens the connections your brain needs to form and recall memories.
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Given that fogginess, I assume.
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Matt Edmundson: Yeah.
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Chris Smith: Yeah.
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And that shrinking real.
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So research has shown that people with chronically high cortal levels often
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have a smaller hippocampus in the brain, so that makes them perform worse
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on memory tasks often, and they might experience faster cognitive decline.
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It is so tricky though because the Hippo Compass also plays a role
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in helping to regulate stress.
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So when it's negatively impacted, it can't keep causal in check.
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This creates a chain where stress just keeps piling on.
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Jen Oliver: Mm-hmm.
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Matt Edmundson: Which is yet another vicious cycle I feel,
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uh, going on in the brain.
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It seems to be happening a lot.
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Um, so what about hormones then?
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How does that affect us?
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Chris Smith: Yeah, so hormones play really important roles in cognitive function.
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So estrogen in particular, this acts as a. A neuroprotective hormone in the brain.
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So it's supporting memory, uh, it's enhancing blood flow and
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it's protecting cells from damage
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Jen Oliver: and during perimenopause and menopause when the estrogen levels drop.
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Um, many women report experiencing brain fog for the first time, and
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studies have documented measurable cognitive changes during these, you
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know, perimenopause and menopause, including difficulties with learning,
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um, verbal memory and concentration.
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Matt Edmundson: So it's not imagining there are genuine
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physiological changes happening.
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Jen Oliver: Absolutely.
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And the brain fog tends to be more pronounced during per perimenopause
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when the hormonal fluctuations are at their greatest, you know, research shows
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and the women will love to hear this.
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Women, they're not just being emotional or stressed.
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Their brains are actually responding to dramatic shifts in.
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Hormone in a hormone that's been protecting and supporting their
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cognitive function for decades.
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Matt Edmundson: Okay.
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So, um, good news in, in some respects.
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Jen Oliver: Yeah.
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Matt Edmundson: Um, so you've mentioned estrogen.
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Um, what other hormones do we need to think about, guys?
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Chris Smith: So, thyroid hormones, uh, they're crucial.
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So these regulate the metabolic rates of every cell in your body.
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And when thyroid hormone levels are low, this is known as hyperthyroidism.
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Uh, brain cell essentially operate in slow motion.
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Matt Edmundson: So foggy thinking then is a direct result of a slowed metabolism.
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Jen Oliver: Precisely.
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Studies have shown that nearly 80% of people with hypothyroidism
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report frequent brain fog symptoms.
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It's like the classic description is sluggish thinking, poor memory, difficulty
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concentrating exactly what you'd expect when your brain's metabolism slows down.
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Mm-hmm.
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Chris Smith: Yeah.
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So.
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Back to big factors, dehydration is really important and it's
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something that people often overlook.
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'cause your brain's over 70% water.
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So even mild dehydration, like losing just one or 2% of body water can
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impair cognitive function, attention.
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Short term memory,
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Matt Edmundson: which again is no surprise, is it after?
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After we learned that in the hydration episode,
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Jen Oliver: we did indeed.
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Yeah.
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When you dehydrated your blood volume decreases.
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Which means you have reduced oxygen and nutrient delivery to your brain cells.
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Your electrolyte imbalances disrupt electrical signals in signal in between
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neurons and dehydration triggers stress hormones, which further impairs cognition.
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Chris Smith: Yeah, and brain scans of dehydrated individuals show they
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have to work much harder to achieve the same cognitive results as those
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people who are perfectly hydrated.
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But fortunately, mild dehydration effects reverse quickly as soon as you rehydrate.
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Matt Edmundson: Very good.
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And you can check out quick plug the, uh, hydration episode.
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It's a good one to check out if you've not heard it already.
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Yeah.
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So what about then, um, the gut connection.
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I've heard a lot about this recently.
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Jen Oliver: Now this is fascinating because the brain and the gut
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communicate bidirectionally.
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That means they communicate both ways through what's called the gut brain axis.
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And this involves neural pathways, clever immune signaling and
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neurotransmitter production.
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Up to 95% of serotonin.
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That's the, the feel good hormone that's crucial for mood and cognition
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is actually produced in your digestive system, not your brain.
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Chris Smith: Yeah.
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And the connections rightly getting a lot of, uh, research focus at the moment.
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So studies have shown that patients with.
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Irritable bowel syndrome or IBS often experience brain fog and some
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of the treatments for IBS that help rebalance gut microbiome can produce
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inflammatory responses, but also improve cognitive symptoms as well.
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Matt Edmundson: Yeah, that's cool man.
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And, and so I guess then when people say trust your gut, there's,
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there's something to that, right?
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Um, like we're relying on a healthy, uh, gut to help us reduce brain fog, which is.
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I guess it's either brilliant or it's slightly terrifying, maybe.
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Or, or, or, or, I dunno.
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Jen Oliver: Or possibly humbling.
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Matt Edmundson: Yeah.
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Yeah, possibly.
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Yeah.
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Yeah, yeah.
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Jen Oliver: But you know, nutritional deficiencies are unsurprisingly really
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important, but often they're overlooked.
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You know, vitamin B twelves really important.
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It's essential for the nerve health, for production of your red blood
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cells that carry oxygen to the brain.
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Chris Smith: Yeah, I mean iron too.
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So when iron levels are low, less oxygen reaches the brain, as you say.
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It leaves you a bit sluggish mentally.
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And don't get me started on vitamin D deficiency or Omega-3 deficiency.
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'cause it will be here all day.
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Matt Edmundson: Yeah, yeah, yeah.
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Your favorite topic, right?
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Favorite topic.
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So, it's fair to say though that the nutrient deficiency has a huge impact.
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So what can you know we, what can people actually do, uh,
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about brain fog apart from.
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Taking more vitamins.
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Jen Oliver: Okay, so start with the fundamentals.
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Sleep, like we've mentioned, is non-negotiable.
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Most adults need seven to nine hours.
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Your brain, it needs that time to go into maintenance mode, to clear
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waste, to consolidate your memories, and to just restore all the chemical
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levels ready for the next day.
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Chris Smith: Yeah, and hydration's key, so keep water available throughout the day.
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If your urine's dark yellow, you need more fluids.
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Uh, for nutrition, do focus on those brain healthy foods.
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So Omega-3 fatty acids, B vitamins, vitamin D, three natural antioxidants,
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and just try to limit those processed foods that could trigger inflammation.
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Matt Edmundson: Okay, that's helpful.
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Now what about stress management then?
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Jen Oliver: Critical, but we all know it's a challenging thing to,
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uh, to manage so chronic stress.
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It, it does physically damage your hippocampus and it's about finding
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out what works for you, whether that's mindfulness, meditation, breathing
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exercises, taking time out to walk outside in nature, the goal is to break that
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cortisol cycle before it becomes chronic
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Chris Smith: and being captain obvious as always, physical exercise.
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It's, it helps enormously.
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Matt Edmundson: It's there.
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Chris Smith: So we know physical activity increases cerebral blood flow.
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That's the blood flow in the brain, but it supports that mitochondrial function.
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You know, those little power stations that I mentioned
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earlier in all of our skin cells.
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Um, but exercise helps to reduce inflammation.
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It regulates stress hormones as well.
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So it's so important, but does make measurable differences.
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Mm-hmm.
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Matt Edmundson: Yeah.
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Ex I mean, exercise is one of those things that you, you always,
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I always feel better after it.
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Yeah.
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Um, I never feel better before it, but I always feel better after it.
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Um, so what about then hormone related brain fog?
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Jen Oliver: So if brain fog coincides with being a certain age of perimenopause
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or menopause, it's worth talking to your doctor because there are
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hormone therapies that can help.
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Um, but you know, it's a, an individual decision and understanding that the
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cognitive changes, they're real and biological, you're not imagining them.
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That is actually can be quite validating.
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Chris Smith: Yeah.
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And for thyroid related brain fog, thyroid hormone replacement is essential.
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You must talk to your doctor about that.
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Matt Edmundson: Yeah, it's great.
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I I When should we, I, it's a big question.
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Is it when should we actually then seek medical help?
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You've both mentioned it,
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Jen Oliver: so I guess when you've done those lifestyle
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changes and they're not enough.
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Or your brain fog is persistent or severe, you know, it could signal
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thyroid dysfunction, hormone imbalance, or autoimmune conditions that actually
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need, you know, specialized treatment.
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Chris Smith: Yeah.
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I think the key is that regular brain fog is an indicator that something
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isn't quite right and needs attention.
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So whether that's sleep or stress or hydration, nutrition, as you mentioned,
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or there could be an underlying condition that needs medical attention.
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So do keep an eye on it.
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It is important.
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Matt Edmundson: Yeah.
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What strikes me, I guess, listening to you guys talk about this is how everything
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is connected and we talk, we've talked about this before in the show, isn't it?
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So poor sleep, stress, gut health, hormones, they're all sort of interlinked.
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Right?
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Jen Oliver: Exactly.
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Sleep is always the answer.
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Matt Edmundson: And earlier when you said sleep, seven to nine hours,
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in my head I heard sleep 79 hours.
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I'm like, that's a good target right there.
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Jen Oliver: Yeah, even seven to nine hours is a good target, but we all
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know that poor sleep increases stress or your ability to handle things.
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Your chronic stress then damages gut health, and then when your gut health
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is damaged, that causes inflammation.
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Then the inflammation affects sleep and the hormonal changes.
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Just amplify all of it.
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Everything is interconnected.
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Chris Smith: I mean, it really is interconnected and it explains why brain
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fog appears across so many conditions.
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So long COVID, as we discussed, it could be chronic fatigue
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syndrome, menopause, thyroid disorders, and auto immune diseases.
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It's just so widespread.
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Mm-hmm.
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Matt Edmundson: Yeah.
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So I guess brain fog then is a bit like, you know, the warning, like you get
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on the dashboard in the car, it's like your brain's warning light going off.
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Jen Oliver: Yeah, precisely.
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But the encouraging news is that for most people.
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It's treatable.
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It's not permanent cognitive decline.
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It's a reversible state that it improves when you address the underlying causes.
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Matt Edmundson: Wonderful.
18:58
So let's recap.
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Why do we get brain fog?
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Chris Smith: So we get brain fog because our brain is an extraordinarily
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demanding organ, requiring optimal conditions to function.
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And when those conditions are met, whether it's through inadequate
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sleep, chronic stress, inflammation.
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Hormonal shifts, uh, nutritional deficiencies or just reduced blood flow.
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Cognitive performance suffers immeasurable and noticeable ways.
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Matt Edmundson: Fair enough.
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So, unlike my laptop, then when it's frozen, I can't just, you
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know, force restart it and quit it.
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I actually have to maintain the system properly.
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Jen Oliver: Exactly.
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Brain fog's telling you that something needs attention.
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But your brain is incredibly resilient.
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And so if you address the underlying cause, give it the support.
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A bit of love and care.
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You know, your cognitive, yeah, your cognitive function typically does.
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It does improve,
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Matt Edmundson: which is good news, right?
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So that's why we experience brain fog and why it's worth taking brain fog
19:59
seriously, rather than just pushing through it and hoping it goes away.
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Jen Oliver: So that's it for this week.
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If this has changed, how you think about those foggy moments,
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hit that subscribe button.
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We're unpacking the science behind everyday questions each week.
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Tell us in the comments what you'd like us to cover.
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Thanks for geeking out with us, but for now, that's it from me.
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Matt Edmundson: That's it from me,
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Chris Smith: and that's it from me
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Jen Oliver: bye for now.