N95 masks increase brain blood velocity and parasympathetic outflow, yet worsen orthostatic symptoms in a healthy cohort

PMCID: PMC12177107

PMID: 40534183

DOI: 10.14814/phy2.70402

Journal: Physiological reports

Publication Date: 2025-6-18

Authors: Pereira TJ, Edgell H

Key Points

• Mask wearing increased systolic cerebral blood flow but paradoxically worsened orthostatic intolerance symptoms
• Total Vanderbilt Orthostatic Symptom Score increased from 12 to 20 during masked trials (p=0.002)
• Psychological factors may play a more substantial role in symptom perception than physiological changes during mask wearing

Summary

This study investigated the physiological and symptomatic effects of N95 mask wearing during orthostatic stress in young, healthy participants. Researchers hypothesized that mask wearing might improve cerebral blood flow during head-up tilt, examining cardiovascular, cerebrovascular, and orthostatic intolerance (OI) responses across masked and control conditions.

Surprisingly, while mask wearing increased systolic middle cerebral artery velocity (MCAv) and decreased cerebrovascular resistance, it also exacerbated orthostatic intolerance symptoms. Participants experienced significantly higher scores for nausea, rapid heartbeat, and shortness of breath during masked trials, with the total OI symptom score increasing from 12 to 20 (p=0.002). The researchers suggest a potential psychological component to symptom experience, noting that the physiological changes were minimal and unlikely to be clinically significant.