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Inhalation flow rates during strenuous exercise.

Johnson AT; Koh FC; Scott WH; Mackey KM; Chen KYS; Rehak T
J Int Soc Respir Prot 2005 Oct; 22(Fall/Winter):79-96
It would be helpful if peak inhalation flow rates were characterized for respiratory design, testing, and use. However, peak flow rates depend strongly on the wearer and the type of work being performed. Instantaneous inhalation rates for subjects exercising on a treadmill have been measured for the following conditions: 1) at 80-85% VO2 max without a respirator, 2) at 80-85% VO2 max while wearing a breath-responsive PAPR (blower flow rate) and 3) at 100% VO2 max without a respirator. Instantaneous inhalation flow rates were found to vary greatly among subjects and at different times for each subject. Depending upon the time that any given flow rate can be sustained, peak flow rates can vary considerably. Instantaneous flow rates were recorded and classified according to 20 L/min ranges so that the flow rate distribution could be obtained. If flow rates in the top one percentile are defined as peak flow rates, then a peak inhalation flow rate of up to 359 L/min (BTPS) was measured for condition 1. Peak instantaneous (less than 1% of flow rates) recorded flows were even higher, up to 442 L/min (BTPS). A peak blower flow rate at up to 679 L/min (BTPS) was measured for condition 2. Flow rates recorded at 100% VO2 Max were generally higher than flow rates 80-85% VO2 max, although this varied somewhat among subjects. A linear relationship has been found between peak flow rate and average minute volume, which can then be used in a procedure to calculate peak flow rates expected at any given work rate.
Respirators; Respiratory-function-tests; Respiratory-rate; Respiratory-protective-equipment; Analytical-processes; Analytical-models; Models
Biological Resources Engineering, University of Maryland, College Park, MD 20742
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Journal of the International Society for Respiratory Protection
Page last reviewed: February 3, 2023
Content source: National Institute for Occupational Safety and Health Education and Information Division