Southwest Center for Occupational and Environmental Health

Health Symposium Recap: Physiological and psychological impacts of fabric face masks in the occupational environment with Mark Wilson, MSPH, PhD, CIH, Tulane University

The 2nd Annual Southwest Centers Occupational Health Research Symposium was held on June 10, 2022. The virtual event, a collaboration between the Southwest Center for Occupational and Environmental Health (SWCOEH) and the Southwest Center for Agricultural Health, Injury Prevention and Education (SW Ag Center). This series will highlight presentations made by awardees of the Pilot Projects Research Training Program who were selected and awarded by the SWCOEH. This program is now in its 22nd year.

In Part V of our series, we discuss “Physiological and psychological impacts of fabric face masks in the occupational environment: an assessment of real perceived heat stress, cardiovascular load, and work rate.” The study was led by with Mark Wilson, MSPH, PhD, CIH, at Tulane University School of Public Health and Tropical Medicine.

“The COVID-19 pandemic brought into light many practices that weren’t considered parts of daily routine,” said Jenil Patel, PhD, the Director of the Pilot Projects Research Training Program at the SWCOEH. “One of these was wearing face masks. A variety of masks emerged in such a short timeframe, with variations in the type of fabric and differing effectiveness. There was a need to study how wearing these in workplaces with challenging conditions changed perceptions among workers. Dr. Wilson’s pilot project brought important findings that demonstrate the challenges that came with wearing fabric masks among workers in hot climates, especially in hotter states like Louisiana.”

SWCOEH.org: What were your main takeaways from the study?

Dr. Wilson: “Fabric face coverings don’t impact heat-stress related physiological endpoints or work rate for short term tasks. Participants reported higher perceived difficulty while wearing fabric face coverings when completing exercise tasks in both elevated and normal temperature conditions.” 

SWCOEH.org: Were you surprised by the study finding that “there was no significant difference in mask use and strain index”? 

Dr. Wilson: “Honestly, for changes in core temperature, no I did not anticipate seeing changes in the different experimental conditions. Considering the short time scale for the exercise tasks and the comparably normal temperature (it is routinely above 85° F here in Louisiana) in the study, I didn’t think that we would see differences in core temperature readings. I was, however, surprised that the integrated strain index, which benchmarks off initial heart rate and core temp, did not show a detectable difference with and without fabric face masks. I really thought, based on my experience exercising while wearing a face covering, that the strain index (which integrates both heart rate and core temperature) would show that the use of face coverings was associated with increased strain. That perception of increased effort was confirmed by the study subjects, but there were no physiological or work rate differences based on mask use during short-term tasks. 

SWCOEH.org: While people felt they were working harder when wearing masks (perceived effort), they in fact were not. Are there other examples of this “placebo-type” effect in your heat stress research? 

Dr. Wilson: Yes, this is the basis of the CAF (clothing adjustment factor) that is part of the ACGIH® TLV® for heat stress evaluation. We know that what people are (or aren’t) wearing can impact their thermoregulatory capacity.

SWCOEH.org: If you had the time and funding for further study in this area, what would you focus on? 

Dr. Wilson: I’d focus on longer study periods, those that reflect real-world working conditions in real-world settings. That way the data would be representative of what kind of conditions people experience during their normal workdays.

The SWCOEH provides a variety of graduate-level training opportunities for occupational and environmental health professionals through our industrial hygiene, occupational and environmental medicine, occupational epidemiology, and Total Worker Health®.