Effect of respirator resistance on tolerant capacity during graded load exercise

Abstract

Respirator breathing resistance impacts performance of wearers during constant work load. However, it is less clear as to how breathing resistance affects the tolerant capacity of users during graded work load. The present study investigated the tolerant capacity of 8 individuals during incremental work load. The 8 subjects were required to wear two matched respirators (respirators I and II which were designed to have different breathing resistances and the same dead space) respectively on separate days and then work to end points. Minute ventilation (V_E), breathing frequency (BF), oxygen consumption (VO₂) and heart rate (HR) were recorded during exercise, while tolerant time, response time and breathing discomfort were measured at the end of each test trial. The test variables were compared between the two respirators by using matched-pairs t-test. The results showed that the tolerant time was significantly reduced for the respirator I with higher level of breathing resistance when compared with its counterpart with lower breathing resistance (respirator II) (P<0.05). The same changes occurred for response time. Results also showed a significant increase in V_E and BF for respirator I wearers when the work load was above 125 W. The O₂ consumption was similar under the two breathing resistance conditions. These findings suggested that the respiratory resistance caused by self-contained breathing apparatus (SCBA) has an impact on the tolerant capacity of users.

References

[1] JohnsonA.T., ScottW.H., LaustedC.G., et al.. Effect of respirator inspiratory resistance level on constant load treadmill work performance. Am Ind Hyg Assoc J, 1999, 60(4): 474-479

[2] CarettiD.M., ScottW.H., JohnsonA.T., et al.. Work performance when breathing through different respirator exhalation resistances. Am Ind Hyg Assoc J, 2001, 62(4): 411-415

[3] PeterB.R., AnnT.D., ThomasO.D.. The physiological consequences of wearing industrial respirators: A review. Am Ind Hyg Assoc J, 1979, 40(6): 517-534

[4] DugganA.. Energy cost of stepping protective clothing ensembles. Ergonomics, 1988, 31(1): 3-11

[5] SeligaR., BhattacharyaA., SuccopP., et al.. Effect of work load and respirator wear on postural stability, heart rate, and perceived exertion. Am Ind Hyg Assoc J, 1991, 52(10): 417-422

[6] WilliamE.N., JoeS., FredricL.G., et al.. Physiological responses during graded treadmill exercise in chemical-resistant personal protective equipment. Preh Emer Care, 2007, 11(4): 394-396

[7] ArthurT.J., CathrynR.D., CharlesO.D.. Respirator mask effects on exercise metabolic measures. Am Ind Hyg Assoc J, 1995, 56(5): 467-473

[8] LouhevaaraV., SmolanderJ., KorhoenO., et al.. Effects of industrial respirators on breathing pattern at different work levels. Eur J Appl Physiol, 1986, 55(2): 142-146

[9] CarettiD.M., CoyneK.M., JohnsonA., et al.. Performance when breathing through different respirator inhalation and exhalation resistances during hard work. J Occup Env Hyg, 2006, 3(4): 214-224

[10] JetteM., ThodenJ., LivingstoneS.. Physiological effects of inspiratory resistance on progressive aerobic work. Eur J Appl, 1990, 60(1): 65-70

[11] LafertyA.E., MckayR.T.. Physiologic effects and measurement of carbon dioxide and oxygen levels during qualitative respirator fit testing. J Chem Health Safety, 2006, 13(5): 22-28

[12] CatettiD.M., WhitleyJ.A.. Exercise performance during inspiratory resistance breathing under exhaustive constant load work. Ergonomics, 1998, 41(4): 501-511

[13] BerndtssonG.. Peak inhalation air flow and minute volumes measured in a bicycle ergometer test. J Int Soc Respir Prot, 2004, 21(5): 21-29

[14] JohnsonA.T., DoolyC.R., CoyneK.M., et al.. Work performance when breathing through very high exhalation resistance. J Int Soc Respir Prot, 1997, 15(2): 25-29

[15] JohnsonA.T., WeissR., GroveC.. Respirator performance rating tables for mask design. Am Ind Hyg Assoc J, 1992, 53(3): 193-202

[16] HarberP., TamimieJ., EmoryJ., et al.. Effects of exercise using industrial respirators. Am Ind Hyg Assoc J, 1984, 45(9): 603-609

[17] HarberP., TamimieJ.M., BhattacharyaA., et al.. Physiologic effect of respirator dead space and resisitance loading. J Occu Med, 1982, 24(9): 681-684

[18] JohnsonA.T., ScottW.H., LaustedC.G., et al.. Effect of external dead volume on performance while wearing a respirator. Am Ind Hyg Assoc J, 2000, 61(5): 678-684

[19] LouhevaaraV., ToumiT., KorhonenO., et al.. Cardiorespiratory effects of respiratory protective devices during exercise in well-trained men. Eur J Appl Physiol, 1984, 52(3): 340-345

[20] YanS., JasonH.T.. Breathing responses to small inspiratory threshold loads in humans. J Appl Physiol, 1999, 86(3): 874-880

[21] MorganW.P.. Psychological problems associated with the wearing of industrial respirators: A review. Am Ind Hyg Assoc J, 1983, 44(9): 671-676

[22] QiuM., LiuB.L., LiuZ.Q.. Effect of SCBA on wearer. CPPE (Chinese), 2008, 89(4): 19-22

[23] DuBoisA.B., HarbZ.F., FoxS.H.. Thermal discomfort of respiratory protective devices. Am Ind Hyg Assoc J, 1990, 51(10): 550-554

[24] JonesJ.G.. The physiological cost of wearing a disposable respirator. Am Ind Hyg Assoc J, 1991, 52(6): 219-225

[25] CarettiD.M.. Cognitive performance and mood during respirator wear and exercise. Am Ind Hyg Assoc J, 1999, 60(2): 213-218

[26] ZimmermanN.J., EbertsC., SalvendyG., et al.. Effects of respirators on performance of physical, psychomotor and cognitive tasks. Ergonomics, 1991, 34(3): 321-334

[27] LairdI.S., GoldsmithR., PackR.J., et al.. The effect on heart rate and facial skin temperature of wearing respiratory protection at work. Annual Occu Hyg, 2002, 46(2): 143-148

[28] JohnsonA.T., DoolyC.R., DotsonC.O.. Respirator mask effects on exercise metabolic measure. Am Ind Hyg Assoc J, 1995, 56(5): 467-473

[29] JohnsonA.T., DoolyC.R., BlanchardC.A., et al.. Influence of anxiety level on work performance with and without a respirator mask. Am Ind Hyg Assoc J, 1995, 56(9): 858-865

[30] QiuM., WangS., LiuT.M.. Analysis on the problems of protective respirators based on ergonomics. China Safety Sci J, 2007, 17(2): 139-143