Why Do We Feel Sluggish When We’re Ill? Scientists Believe It’s Due to Inflammation


Nov 28, 2019


When we’re ill, we often feel sluggish — that is, as if there’s a fog that’s spread over our brain, making us unable to think, understand, remember or pay attention to what’s happening around us. Scientists believe this brain fog could be linked to the inflammation that occurs in our bodies when we’re ill. Published in Neuroimage, their research states inflammation is linked to the brain’s inability to reach and maintain alertness when ill.

Brain fog is often the symptom of various types of illnesses and conditions like fibromyalgia, chronic fatigue syndrome, sleep apnea, multiple sclerosis, even stress, pregnancy, and unhealthy diets, according to Medical News Today.

“Scientists have long suspected a link between inflammation and cognition, but it is very difficult to be clear about the cause and effect. For example, people living with a medical condition or being very overweight might complain of cognitive impairment, but it’s hard to tell if that’s due to the inflammation associated with these conditions or if there are other reasons,” Ali Mazaheri, co-author and associate professor at the University of Birmingham, said in a statement

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Researchers injected twenty young male volunteers with a salmonella typhoid vaccine (that causes temporary inflammation and no other side effects). Each volunteer’s inflammation was measured by analyzing their blood. Then, they were tested for their cognition and ability to remain alert, stay oriented and pay attention via responses to simple images on a computer screen.

On a different day, they were injected with placebo (water) and then given cognition and attention tests to perform again. Results showed that inflammation specifically affected brain activity related to staying alert.

“Getting a better understanding of the relationships between inflammation and brain function will help us investigate other ways to treat some of these conditions. For example, further research might show that patients with conditions associated with chronic inflammation, such as obesity, kidney disease or Alzheimer’s, could benefit from taking anti-inflammatory drugs to help preserve or improve cognitive function,” Leonie Balter, co-author of the study, said in a statement.

Balter added, “Furthermore, subtle changes in brain function may be used as an early marker cognitive deterioration in patients with inflammatory diseases.”


Written By Aditi Murti

Aditi Murti is a culture writer at The Swaddle. Previously, she worked as a freelance journalist focused on gender and cities. Find her on social media @aditimurti.


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