23 Jun 2023 • In a new research letter in the JAMA Network Open, researchers conclude that wearing an N95 mask for a prolonged period could affect physiologic and biochemical parameters. The authors report that the effect was primarily initiated by increased respiratory resistance and subsequent decreased blood oxygen and pH, which contributed to sympathoadrenal system activation and epinephrine as well as norepinephrine secretion elevation, and a compensatory increase in heart rate and blood pressure.

The study involves 30 healthy adults wearing an N95 while awake and living in a metabolic chamber where the atmosphere, caloric intake and the physical activity levels of the participants could be controlled. Twice a day, for thirty minutes, the participants “exercised” using an arm ergometer at a “light” intensity, 40% of their maximal effort.

Compared to not wearing a mask at all,

• Wearing the N95 mask slowed respirations, decreased oxygen saturation, and increased heart rates by about 4 beats/minute.
• Exercising while wearing the N95 mask increased heart rate by an additional 8 beats/minute and raised systolic blood pressure by about 6 mm Hg and diastolic by 5mm Hg.
• These physiologic changes resulted in slightly increased fat oxidation and energy expenditure.
• There were also increases in metanephrine and normetanephrine levels

The bottom line is that masks alter our physiologic responses as we should anticipate; and our bodies automatically compensate - that is what homeostasis is about. For individuals with already compromised physiology, the elderly as a generalization, and those with pulmonary disease, more specifically, the protection from infection afforded by masks can be weighed against their discomfort, and perhaps some transient worsening of some physiologic parameters.

Source: ACSH | Read full story