Exercise Limitation Imposed by an Approved Air Purifying Respirator (APR)
Abstract
In this IRB-approved study, 31 subjects exercised with and without an approved air purifying respirator (APR). A commonly used gas mask was used in both standard and slightly altered configurations; in Phase1 the filter was loaded for a pressure drop simulating dust loading, and in Phase 2 the inlet pathway in the mask was modified. Phase 1 exercises were short (fire hose drag) or long duration (incremental-load treadmill running, ladder climbing, and self-paced box lifting). Phase 2 exercise was incremental and endurance treadmill running. Parameters measured and calculated included breathing frequency, tidal volume, respiratory duty cycle, mask pressure, resistive effort (WOB/VT), minute ventilation (VE), peak inspiratory flow (Vi peak), rate of O2 uptake (VO2), inhaled and exhaled CO2, and heart rate. With a standard APR, breathing difficulty caused 22 of 30 subjects to stop incremental running,14 of 15 to stop endurance runs, and 1 of 15 to stop climbing (6 of 15 with the loaded filter). With the standard APR, duration of incremental treadmill running dropped 14% from that with no APR, running endurance time decreased 57%, and climbing endurance dropped by 20%. The standard APR did not affect load lift and transfer or fire hose drag performance, but the number of boxes moved decreased 8% with the loaded filter, and five subjects complained of breathing resistance during recovery from the hose drag. Without an APR, the highest sustained VE exceeded 150 L/min, and Vi was recorded at 434 L/min. With an APR, VE decreased 14% to 26% relative to that without an APR at the same workload. Peak attainable VO2 was reduced 15%, and VO2 at end running endurance decreased 15 to 18%. Because required inspiratory pressures from laminar and turbulent flow were so high at the necessary Vi, inspiratory WOB/VT was excessive.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2010
- Accession Number
- AD1000606
Entities
People
- Barbara Shykoff
- Dan Warkander
- Donika Winters
Organizations
- United States Navy Experimental Diving Unit