What Causes Brain Fog — And How To Finally Clear Your Mind

Adequate sleep is key to performing our best.

What Causes Brain Fog And Why Sleep Is Important For Anxiety Relief getty

What causes brain fog and what is its connection with anxiety disorders and a lack of sleep?

A foggy brain is that feeling of your thinking and processing slowing down. You feel a bit disconnected and not completely "there" and maybe you feel a little "off" and "not sharp." Some people describe it feeling like "mental quicksand" that, for some reason, they’re simply not able to correct.

Anxiety causes physiological arousal. When anxiety kicks in, we feel motivated to take action...now. We feel energized and alert.


So what causes brain fog? And how do these two different experiences — brain fog and anxiety — become entangled? 

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Brain fog caused by anxiety may occur due to a symptom of anxiety and vice versa. The results can be an escalating, reinforcing feedback loop.


When the signs of anxiety are already present, the worry, racing thoughts and ruminating literally exhaust the mind. And this sort of exhaustion can allow the experience of brain fog to take over and decrease alertness and overall processing.

One of the prime culprits in setting the stage for an anxious and foggy brain appears to be inadequate sleep.

Sleep deprivation doesn’t just affect those of us with anxiety. A full 40 percent of Americans are chronically sleep-deprived.

Why is sleep important? How does it help with anxiety relief and a clearer brain?

Scientists have recently discovered a tiny network of fluid-filled channels that clear toxins from brain cells. The toxins are created while we’re awake and cleared out while we sleep because that’s the only time this tiny network activates. Like with other bodily functions, we need sleep to allow our brain to rejuvenate and restore itself.


Emily Underwood, a Science magazine writer, dubbed sleep as the brain’s housekeeper.

Unless we sleep, our brains cannot get cleaned. Further, if we don’t sleep long enough, our brains won’t get the deep cleaning they need to perform at their best. Without the deep cleaning, we’re at risk for brain fog.

Sleep loss also saps energy, efficiency, concentration, and emotional control. For those of us who already wrestle with anxiety, inadequate sleep can make things worse, particularly escalating anticipatory anxiety.

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A brain without sleep struggles to think clearly and manage emotional reactions. That’s because of the part of the brain associated with this function, the medial prefrontal cortex (mPFC), is impaired with inadequate sleep.


A brain with inadequate rest is also less able to notice the positive. Since noticing the positive is a critical tool in using anxiety to work for you instead of feeling at its mercy, a lack of sleep can exacerbate anxiety which can, in turn, induce brain fog.

Sleeping is critical to staving off brain fog associated with anxiety, but the fact remains that many of us with anxiety struggle with insomnia. Getting adequate sleep isn’t always easy, or seemingly possible when you struggle with anxiety.

How can you set yourself up for anxiety relief and sleeping success?

Here are 4 ways to do it.

1. Go to bed a bit earlier.

This is the best way to increase sleep.


Yet, it’s okay to start small. Aim for just 10-15 minutes more sleep every night.

2. Resist the urge to push through fatigue and do that "one more thing."

Ignoring drowsy cues is one of the ways people condition themselves to stay awake. By doing so, they create a dangerous cycle of not feeling fatigued.

If you struggle to get to sleep, be on the lookout for the first drowsy cue you feel and seize it. Get into bed. Turn out the lights. Allow yourself to drift with the drowsiness toward sleep.

3. Be particularly mindful of screens.

The blue light behind most screens is the same frequency as the blue light of dawn.

This frequency has been shown to stop the production of melatonin (the neurotransmitter associated with sleep) to prepare for waking which is the last thing anyone trying to get some shut-eye needs.


4. Practice good sleep hygiene.

Sleep hygiene includes behavioral and environmental practices to promote better quality sleep. A good night’s sleep begins with decreasing the stimulation you’re exposed to a full hour before you want to sleep.

Be mindful of stimulation levels of all sorts, visual, auditory, and tactile. Get into comfortable clothes. Turn the lights down or off and light some candles. Turn off music, the TV, your computer, and phone.

By prioritizing adequate sleep, you’ll find that your anxiety is easier to manage and use for your benefit. You will also most likely find that brain fog caused or exacerbated by anxiety falls by the wayside. Your mental processing, mood, and alertness will likely elevate as well.


Imagine, simply by allowing yourself to get more adequate rest, you could feel like a different person because your brain fog has lifted.

RELATED: If You Really Want A Good Night's Sleep, Here's Why You And Your Partner Should Start Sleeping Apart

Dr. Alicia Clark is a Licensed Clinical Psychologist. Looking for more help with anxiety? Check out her new book, Hack Your Anxiety and sign-up for book bonuses including a free mini e-course to help you understand how anxiety impacts your life and how to hack its most common challenges.

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