You know how people say things like “a strong mind equals a strong body”? Well, a team of researchers from the University of Michigan believes there could be a literal undertone to that quote as they suggest that lacking mental alertness could put you at high risk of viral infections.

The findings published by a team of researchers from the University of Michigan in collaboration with researchers from Duke University School of Medicine, and the University of Virginia say that when a person’s cognitive functioning isn’t sharp as a tack, they not only become likely to experience more symptoms from respiratory infections, but they tend to be more contagious too. 

It is known, mostly from experience, that when a person suffers from bouts of stress and lack of sleep the immune system becomes weak leaving you susceptible to illnesses like the common cold or the flu. With variations in brain functioning being a known trigger for stress and poor sleep, the study’s authors set out to see if it can serve as a tool for predicting just how serious infections can be. 

“This is the first exposure study in humans to show that one’s cognitive performance before exposure to a respiratory virus can predict the severity of the infection,” says Alfred Hero, Distinguished Professor of Electrical Engineering and Computer Science at the University of Michigan and co-author of the study. 

Study Methodology

To arrive at their findings, 18 healthy volunteers were recruited, all of whom participated in brain performance tests three times a day for three days using a digital self-test in their homes. The tests measured reaction time, attention, rapid switching between numbers and symbols, etc.

Afterward, each participant was deliberately infected with the human rhinovirus – the virus responsible for the common cold upon which variables including symptom severity, viral shedding, and cognitive function were collected. 

The participants recorded their symptoms in a symptom diary and rated themselves on a scale of 1-3 on eight common cold symptoms, while viral shedding, a measure of transmissibility, was determined by washing out nasal passages with saline solution and then examining the viral presence in the fluid through culturing.

Results

The results obtained, although inconclusive at first, eventually reflected a direct correlation between cognitive variability or mental alertness before exposure and infection severity. 

“In the beginning, we didn’t find that cognitive function had a significant association with susceptibility to illness because we used the raw scores. But later, when we looked at change over time, we found that variation in cognitive function is closely related to immunity and susceptibility,” says lead author Yaya Zhai, a recent Ph.D. graduate in bioinformatics at U-M.

Despite its limitations, the study’s findings suggest a useful tool in predicting susceptibility and severity of infections which if properly developed could have monumental clinical and epidemiological applications.

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