Better Me

“What Was I Saying Again?” Six Common Causes for Brain Fog

Darn it! Where did I park my car again?

Wait, what was I saying?

At some point or another, we’ve all had these thoughts. Whether you’re unsure where you parked at the grocery store or you’ve lost your train of thought during a great story, brain lapses happen to us all. It’s called brain fog, or among some parents, “mommy brain."

But why does this happen and is it something to be concerned about?

What is brain fog and what does brain fog feel like?

“‘Brain fog’ is not a medical condition, disease or disorder.  It is a set of symptoms that include a general feeling of fatigue and cognitive inefficiencies, such as reduced concentration and difficulty with memory,” said Cynthia Funes, PhD, a clinical neuropsychologist at Banner – University Medicine Neurosurgery Clinic in Phoenix, AZ. “Patients often describe that brain fog feels like having a ‘cloud inside their head’ that makes it difficult for them to focus on daily tasks.”

You’ve probably heard about brain fog more these days and maybe even experienced the symptoms on your own. Typical symptoms of brain fog include poor concentration, an extra effort to focus on a task or pay attention, trouble multitasking or managing too many tasks at once, trouble tracking what you are doing (i.e., “Why did I just walk into this room?”) and trouble retrieving a memory or information.

To better understand the causes and when you should be concerned, here’s a breakdown of things that contribute to brain fog.

6 common causes for brain fog

  1. An inflammatory response. While we mostly relate inflammation to joints, did you know your brain can become inflamed too? While it won’t hurt, it will cause you to feel foggy-headed and sluggish. This can be due to a number of factors, including obesity, chronic fatigue syndrome, multiple sclerosis, inflammatory diseases and autoimmune disorders like fibromyalgia.
  2. Asthma and allergies. Histamines are a chemical the body produces when it encounters an allergen. Those with asthma and allergies commonly report fogginess, which is in part due to a high production of histamine.
  3. Anxiety, depression and stress. Your brain is a computer, and when you have ongoing mental health issues like anxiety, depression and stress or chronic fatigue it can really bog down your system and memory. And with these stressors constantly on the brain, it may be difficult to focus on work or even household tasks.
  4. Cancer treatments. Known as “chemo brain,” it isn’t unusual during and after cancer treatment for you to feel a bit foggy. This side effect is most commonly connected with chemotherapy, but other treatments may be associated. These treatments can cause short-term, long-term and delayed mental changes or cognitive problems.
  5. Hormonal changes. “Baby or mommy brain” can be a very real thing, especially for women who are pregnant or going through menopause. In men, a lower testosterone level can also explain mental fatigue.
  6. Sleep. There’s nothing like a good night’s rest, but if you aren’t getting it, you’re likely feeling less with it. A sleep disorder or lack of sleep can disrupt your brain cells’ ability to communicate with each other, leading to a temporary brain lapse that can affect memory and visual perception.

Although the actual cause or causes are still being researched, brain fog has also been associated with long COVID, a condition where symptoms of a COVID-19 illness linger more than 30 days after the onset and recovery of the initial illness. 

What can you do to clear the fog?

Brain fog treatment will often depend on the root cause, but there are some things you can do at home to keep your mind sharp and more alert. These include:

  • Participating in activities that increase alertness, energy and brain health/power, such as regular physical activity and meditation or trying activities like crosswords and Sudoku or working on a puzzle.
  • Getting plenty of sleep.
  • Eating a healthy diet rich in fruits, vegetables and healthy fats and whole grains.
  • Managing stress by knowing your limitations. For example, completing tasks one at a time, making checklists to ensure that you are remembering to complete all aspects of a task and setting reminders for important upcoming events can help take the pressure off of your brain.

Should I get help?

If you’re feeling bit foggier these days and nothing seems to help clear your head—in fact, things seem to be getting worse—contact your doctor right away.

“Doctors can provide treatment for the conditions typically related to brain fog and can also ensure that what you are feeling is truly 'brain fog' and not the emergence of some other condition,” Dr. Funes said. “For example, sometimes we can feel foggy or have cognitive difficulties if we are deficient in some important vitamins and minerals. Sometimes cognitive symptoms can point to a larger difficulty that can be identified by a specialist who works with patients with cognitive difficulties. So, following up with your doctor is important.”

To find a Banner Health specialist near you, visit

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Content in this article was updated on March 12, 2024. 

Wellness Neurosciences Behavioral Health