Feeling Sluggish? It Might be Inflammation. | E-Counseling.com

Feeling Sluggish? It Might be Inflammation.

Maria Morioka, BSN, RN
November 28, 2019
brain fog

Inflammation has gotten a bad rap lately. It’s blamed for heart problems, depression, and Alzheimer’s disease. Now you can add “brain fog” to the list.

Researchers at the University of Birmingham, along with the University of Amsterdam, performed a study on 20 male volunteers to evaluate the connection between inflammation and brain activity. What they found was a link between inflammation and cognitive visual attention, or what is more commonly known as “brain fog.” 

Brain Fog and Inflammation Explained

Brain fog, or “sluggishness,” can be described as the inability to think or reason clearly due to diminished mental capacity. Brain fog is often temporary and strikes when a person feels ill, tired, or stressed.

Inflammation is a necessary biological response. It occurs as a natural immune response to an injury or outside antigen or irritant, causing redness, swelling, pain, or loss of function to an area. Inflammation helps the body by releasing substances like bradykinin and histamine. These substances cause vessels in the affected area to enlarge and increase blood flow. The enlarged area allows more blood and immune system cells to get the affected site and treat the situation.

Unfortunately, sometimes inflammation can be detrimental to the body, especially when it is prolonged or unnecessary. In the case of an autoimmune disorder, for example, the body mistakenly fights its own cells, causing inflammation where the body doesn’t require it.

How Inflammation Affects The Brain

The study, published in Neuroimage, observed volunteers after they were injected with a small amount of salmonella vaccine. The vaccine caused temporary inflammation, with no other side effects. The vaccine was necessary to examine any links between brain functioning and inflammation. On a separate day, the volunteers were administered a placebo to act as a control group for comparison.

On both days, the vaccine day and the placebo day, the participants were asked to play games and fulfill tasks on a computer while researches monitored their brain activity. Brain activity was observed using an EEG.

The participants were given tasks to complete in three areas: “alerting” “orienting” and “executive control.” Alerting tasks measured obtaining and staying at an alert state. Orienting involved filtering and selecting useful sensory information. Executive control involves filtering useful information from conflicting data.

What the researchers found was that on the days the vaccine was administered, inflammation specifically affected task-related brain activity. Inflammation did not affect decision or judgment (executive control areas of the brain), but it did affect alertness. The brain, when inflamed, showed delays in reaching and maintaining an alert state. 

Researchers and even some laypeople have long since suspected that a connection must be present between feeling ill and feeling “sluggish.” However, it has been challenging to prove any correlation between the two. The study is confirmation that the brain does temporarily become slower when inflamed.


The study adds to a growing number of research highlighting the connection between physical health and mental function. It could also guide physicians toward ways anti-inflammatory drugs can be used in cases of chronic diseases, such as Alzheimer’s or kidney disease, to help cognitive function and improve quality of life.

Much research still needs to be done to understand the full implications of inflammation on the brain. The study also suggests uses for cognitive testing as an early indicator of chronic inflammatory diseases. Further research into inflammation’s affect on the brain may even include memory and behavior. 

For individuals who may be feeling “brain fog” or “sluggishness,” it may be an indication of the need for some rest and relaxation to help any illness and injury heal. Now you know that “brain fog” is not all in your head!

Maria Morioka, BSN, RN

Maria Morioka, BSN, RN has been a Licensed Registered Nurse in the mental health field for nearly 15 years. Maria strongly believes in educating others about the importance of mental health.

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