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Dreger RW. Impact of fire protective equipment and the self-contained breathing apparatus on peak exercise in males and females. ERGONOMICS 2023; 66:1884-1891. [PMID: 36634243 DOI: 10.1080/00140139.2023.2168766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
With an increase in the number of females entering the fire service it is important to understand the potential impact of personal protective equipment (PPE) on females. This study compared selected physiological responses during two graded exercise tests (GXT) performed in a counterbalanced design: GXTPT - wearing athletic clothing while breathing through a low-resistance valve; and GXTPPE - wearing PPE and breathing from a self-contained breathing apparatus (SCBA). Sixteen males and 15 females acted as participants. V ˙ O2peak was significantly lower, by approximately 15%, during the GXTPPE compared to the GXTPT condition for both the males and females. Physiologically, the decreased oxygen consumption was strongly related to an attenuated ventilation (r = 0.75 and 0.71) and oxygen pulse (r = 0.94 and 0.93) for the males and females, respectively. The results of this investigation demonstrate that the SCBA and PPE impacts males and females to a similar relative extent and manner. Practitioner summary: Little information exists regarding the impact of the SCBA and PPE on physiological parameters for females. This investigation determined that females have reduced exercise capacities to the same extent as males, which should be considered when evaluating the aerobic demands of fire suppression work and the fitness levels of firefighters.Abbreviations: GXT: graded exercise test; SCBA: self-contained breathing apparatus; personal protective equipment; MMC: metabolic measurement cart; ANOVA: analysis of variance; RPE: rating of percieved exertion; PRD: perceptions of respiratory distress; PTD: percieved thermal distress; V ˙ O2: rate of oxygen consumption; V ˙ O2peak: rate of oxygen consumption at peak exercise; V ˙ Epeak: minute ventilation at peak exercise; V ˙ E/V ˙ CO2: ventilatory equivalent for carbon dioxide; FVC: forced vital capacity; FEV1: forced expiratory volume in one second; FEF25-75%: forced expiratory flow; PEF: peak expiratory flow rate; MVV: maximum voluntary ventilation.
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Affiliation(s)
- Randy William Dreger
- School of Health and Life Sciences, Northern Alberta Institute of Technology, Edmonton, Canada
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2
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Ehnes CM, Scarlett MP, Adams EM, Dreger RW, Petersen SR. Physiological responses to treadmill exercise in size- and fitness-matched male and female firefighter applicants. ERGONOMICS 2023; 66:1582-1593. [PMID: 36503410 DOI: 10.1080/00140139.2022.2157494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Physiological responses during a standardised treadmill test for structural firefighting employment were compared in 41 pairs of size-matched, male and female applicants. Applicants wore personal exercise clothing, running shoes, and fire protective ensemble with self-contained breathing apparatus (added mass 21.2 ± 1.0 kg). Applicants walked at 1.56 m·s-1, completing a 5-min warm-up, 8-min at 10% grade, and then, progressive 1-min stages to exhaustion. The cut-score required completion of 13-min of exercise. Up to the cut-score, no differences in heart rate, oxygen uptake or minute ventilation were detected between sexes. At time 12:30-13:00 min, V̇O2 was 45.7 ± 0.6 vs. 44.2 ± 0.5 mL·kg-1·min-1 (body mass) for males and females, respectively. Despite similar physiological responses at minute 13, females worked at higher fractions of peak than males (p < 0.05). A second analysis compared a subset of 27 fitness-matched (V̇O2peak) male-female pairs. Fitness-matching further reduced or eliminated most observed differences in physiological responses, except small differences in breathing pattern. Practitioner Summary: Physiological responses during a standardised treadmill test for firefighter applicants were investigated in male and female applicants matched on size and fitness. Absolute responses to exercise were the same for both sexes when size-matched, but relative intensity was higher for females. Fitness-matching reduced or eliminated most previously observed differences. Abbreviations: NFPA: National Fire Protection Association; V̇O2: rate of oxygen consumption; V̇O2peak: rate of oxygen consumption at peak exercise; PAR-Q+: Physical Activity Readiness Questionnaire Plus; SCBA: self-contained breathing apparatus; ANOVA: analysis of variance; V̇E: minute ventilation; V̇Epeak: minute ventilation at peak exercise; V̇E/V̇O2: ventilatory equivalent for oxygen.
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Affiliation(s)
- Cameron M Ehnes
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Michael P Scarlett
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Eric M Adams
- Faculty of Law, University of Alberta, Edmonton, AB, Canada
| | - Randy W Dreger
- School of Health and Life Sciences, Northern Alberta Institute of Technology, Edmonton, AB, Canada
| | - Stewart R Petersen
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
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Li J, Wang Y, Jiang R, Li J. Quantifying self-contained breathing apparatus on physiology and psychological responses during firefighting: a systematic review and meta-analysis. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2023; 29:77-89. [PMID: 34983320 DOI: 10.1080/10803548.2021.2024020] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Objectives. There is no consensus regarding the efficacy of self-contained breathing apparatus (SCBA) on firefighters' physiological and psychological stress responses. This study synthesized and quantified the psycho-physiological demands placed on firefighters wearing SCBA compared to a control group. Methods. Five databases were searched with English-language restrictions from inception to January 2021. As dependent variables, physiological (rectal temperature [Tre], mean skin temperature [T¯sk], heart rate [HR], maximal heart rate [HRmax], maximum oxygen uptake [VO2max], total sweat rate [TSR]) and psychological (rating of perceived exertion [RPE] and thermal sensation [TS]) responses were continuously collected. This study is registered with PROSPERO (CRD42021228363). Results. Nine eligible studies with 289 participants met the inclusion criteria. The pooled estimates for VO2max statistically significantly decreased, whereas T¯sk, HR, HRmax, TSR and RPE increased significantly. Additionally, the Tre and TS parameters were elevated but not significant. Subgroup analysis revealed that, except for VO2max and TSR, the SCBA weight did not differ significantly between groups on any outcome measure. Conclusions. Our meta-analysis indicates that wearing SCBA elicits thermoregulatory, metabolic and psychological stress. However, this is not primarily explained by the weight of SCBA, highlighting the value of ergonomic design and physiological monitoring.
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Affiliation(s)
- Jian Li
- College of Fashion and Design, Donghua University, People's Republic of China
| | - Yunyi Wang
- College of Fashion and Design, Donghua University, People's Republic of China.,Ministry of Education, Donghua University, People's Republic of China
| | - Rongfan Jiang
- College of Fashion and Design, Donghua University, People's Republic of China
| | - Jun Li
- College of Fashion and Design, Donghua University, People's Republic of China.,Ministry of Education, Donghua University, People's Republic of China
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Faghy MA, Shei R, Armstrong NCD, White M, Lomax M. Physiological impact of load carriage exercise: Current understanding and future research directions. Physiol Rep 2022; 10:e15502. [PMID: 36324291 PMCID: PMC9630762 DOI: 10.14814/phy2.15502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 09/18/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Load carriage (LC) refers to the use of personal protective equipment (PPE) and/or load-bearing apparatus that is mostly worn over the thoracic cavity. A commonplace task across various physically demanding occupational groups, the mass being carried during LC duties can approach the wearer's body mass. When compared to unloaded exercise, LC imposes additional physiological stress that negatively impacts the respiratory system by restricting chest wall movement and altering ventilatory mechanics as well as circulatory responses. Consequently, LC activities accelerate the development of fatigue in the respiratory muscles and reduce exercise performance in occupational tasks. Therefore, understanding the implications of LC and the effects specific factors have on physiological capacities during LC activity are important to the implementation of effective mitigation strategies to ameliorate the detrimental effects of thoracic LC. Accordingly, this review highlights the current physiological understanding of LC activities and outlines the knowledge and efficacy of current interventions and research that have attempted to improve LC performance, whilst also highlighting pertinent knowledge gaps that must be explored via future research activities.
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Affiliation(s)
- Mark A. Faghy
- Biomedical Research Theme, School of Human SciencesUniversity of DerbyDerbyUK
| | - Ren‐Jay Shei
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Nicola C. D. Armstrong
- Defence Science and Technology LaboratorySalisburyUK
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
| | - Mark White
- Rocky Mountain University of Health ProfessionsProvoUtahUSA
| | - Mitch Lomax
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
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Mann LM, Granger EA, Chan JS, Yu A, Molgat-Seon Y, Dominelli PB. Minimizing airflow turbulence in women lowers the work of breathing to levels similar to men. J Appl Physiol (1985) 2020; 129:410-418. [PMID: 32702273 DOI: 10.1152/japplphysiol.00347.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Smaller airways increase resistance and the propensity toward turbulent airflow, both of which are thought to be mechanisms behind greater resistive and total work of breathing (Wb) in females. Previous research examining the effect of airway size on the Wb between the sexes is limited by the inability to experimentally manipulate airway size. Heliox (21% oxygen, balance helium) is less dense than room air, which reduces turbulent airflow and airway resistance. The purpose of our study was to utilize heliox inspiration in women to provide a stimulus physiologically similar to increasing airway size. We hypothesized that when breathing heliox women would have a Wb similar to men breathing room air. Eighteen healthy young subjects (n = 9 women, 9 men) completed two maximal exercise tests on a cycle ergometer over 2 days. Subjects breathed room air for one test and heliox for the other. Wb was assessed with an esophageal balloon catheter. During the room air trial, when ventilations were >65 L/min, women had a significantly greater Wb compared with men (P < 0.05). The greater Wb in women was due to greater resistance to turbulent flow. For both sexes, breathing heliox resulted in increased expiratory flow (+132 ± 18% of room air), an elimination of expiratory flow limitation, and a reduction in Wb (69 ± 12% of room air) (all P < 0.05). When the women were breathing heliox, Wb was not different from that in the men breathing room air. Our findings support the idea that the smaller conducting airways in females are responsible for a greater total and resistive Wb.NEW & NOTEWORTHY When healthy young women breathe heliox gas during exercise, their work of breathing is not different from men breathing room air. Heliox inspiration reduces airway resistance and promotes laminar flow, which is a physiologically similar effect of increasing airway size. Our findings provide experimental evidence that smaller airways in women are responsible for the greater work of breathing during exercise.
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Affiliation(s)
- Leah M Mann
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Emily A Granger
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Jason S Chan
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Annie Yu
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Yannick Molgat-Seon
- Department of Kinesiology and Applied Health, Gupta Faculty of Kinesiology and Applied Health, University of Winnipeg, Winnipeg, Manitoba, Canada.,Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Paolo B Dominelli
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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Hostler D, Pendergast DR. Respiratory Responses during Exercise in Self-contained Breathing Apparatus among Firefighters and Nonfirefighters. Saf Health Work 2018; 9:468-472. [PMID: 30559997 PMCID: PMC6284167 DOI: 10.1016/j.shaw.2018.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 09/08/2017] [Accepted: 02/09/2018] [Indexed: 11/28/2022] Open
Abstract
Background Firefighters are required to use self-contained breathing apparatus (SCBA), which impairs ventilatory mechanics. We hypothesized that firefighters have elevated arterial CO2 when using SCBA. Methods Firefighters and controls performed a maximal exercise test on a cycle ergometer and two graded exercise tests (GXTs) at 25%, 50%, and 70% of their maximal aerobic power, once with a SCBA facemask and once with protective clothing and full SCBA. Results Respiratory rate increased more in controls than firefighters. Heart rate increased as a function of oxygen consumption (V.O2) more in controls than firefighters. End-tidal CO2 (ETCO2) during the GXTs was not affected by work rate in either group for either condition but was higher in firefighters at all work rates in both GXTs. SCBA increased ETCO2 in controls but not firefighters. Conclusions The present study showed that when compared to controls, firefighters’ hypoventilate during a maximal test and GXT. The hypoventilation resulted in increased ETCO2, and presumably increased arterial CO2, during exertion. It is proposed that firefighters have altered CO2 sensitivity due to voluntary hypoventilation during training and work. Confirmation of low CO2 sensitivity and the consequence of this on performance and long-term health remain to be determined.
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Affiliation(s)
- David Hostler
- SUNY University at Buffalo, Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments (CRESE), USA
| | - David R Pendergast
- SUNY University at Buffalo, Department of Physiology and Biophysics, USA
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Petersen SR, Anderson GS, Tipton MJ, Docherty D, Graham TE, Sharkey BJ, Taylor NA. Towards best practice in physical and physiological employment standards. Appl Physiol Nutr Metab 2016; 41:S47-62. [DOI: 10.1139/apnm-2016-0003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
While the scope of the term physical employment standards is wide, the principal focus of this paper is on standards related to physiological evaluation of readiness for work. Common applications of such employment standards for work are in public safety and emergency response occupations (e.g., police, firefighting, military), and there is an ever-present need to maximize the scientific quality of this research. Historically, most of these occupations are male-dominated, which leads to potential sex bias during physical demands analysis and determining performance thresholds. It is often assumed that older workers advance to positions with lower physical demand. However, this is not always true, which raises concerns about the long-term maintenance of physiological readiness. Traditionally, little attention has been paid to the inevitable margin of uncertainty that exists around cut-scores. Establishing confidence intervals around the cut-score can reduce for this uncertainty. It may also be necessary to consider the effects of practise and biological variability on test scores. Most tests of readiness for work are conducted under near perfect conditions, while many emergency responses take place under far more demanding and unpredictable conditions. The potential impact of protective clothing, respiratory protection, load carriage, environmental conditions, nutrition, fatigue, sensory deprivation, and stress should also be considered when evaluating readiness for work. In this paper, we seek to establish uniformity in terminology in this field, identify key areas of concern, provide recommendations to improve both scientific and professional practice, and identify priorities for future research.
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Affiliation(s)
- Stewart R. Petersen
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
| | | | - Michael J. Tipton
- Department of Sport and Exercise Sciences, University of Portsmouth, Portsmouth, Hants, PO1 2ER, UK
| | - David Docherty
- School of Exercise Science, Physical & Health Education, University of Victoria, Victoria, BC V8P 5C2, Canada
| | - Terry E. Graham
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Brian J. Sharkey
- Department of Health and Human Performance, University of Montana, Missoula, MT 59812, USA
| | - Nigel A.S. Taylor
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
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8
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McLellan TM, Havenith G. Protective clothing ensembles and physical employment standards. Appl Physiol Nutr Metab 2016; 41:S121-30. [DOI: 10.1139/apnm-2015-0474] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physical employment standards (PESs) exist for certain occupational groups that also require the use of protective clothing ensembles (PCEs) during their normal work. This review addresses whether these current PESs appropriately incorporate the physiological burden associated with wearing PCEs during respective tasks. Metabolic heat production increases because of wearing PCE; this increase is greater than that because of simply the weight of the clothing and can vary 2-fold among individuals. This variation negates a simple adjustment to the PES for the effect of the clothing on metabolic rate. As a result, PES testing that only simulates the weight of the clothing and protective equipment does not adequately accommodate this effect. The physiological heat strain associated with the use of PCEs is also not addressed with current PESs. Typically the selection tests of a PES lasts less than 20 min, whereas the requirement for use of PCE in the workplace may approach 1 h before cooling strategies can be employed. One option that might be considered is to construct a heat stress test that requires new recruits and incumbents to work for a predetermined duration while exposed to a warm environmental temperature while wearing the PCE.
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Affiliation(s)
- Tom M. McLellan
- TM McLellan Research Inc., 25 Dorman Drive, Stouffville, ON L4A 8A7, Canada
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, UK
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9
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Phillips DB, Stickland MK, Petersen SR. Ventilatory responses to prolonged exercise with heavy load carriage. Eur J Appl Physiol 2015; 116:19-27. [DOI: 10.1007/s00421-015-3240-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
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10
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Faghy MA, Brown PI. Thoracic load carriage-induced respiratory muscle fatigue. Eur J Appl Physiol 2014; 114:1085-93. [DOI: 10.1007/s00421-014-2839-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
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11
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Dominelli PB, Sheel AW, Foster GE. Effect of carrying a weighted backpack on lung mechanics during treadmill walking in healthy men. Eur J Appl Physiol 2011; 112:2001-12. [PMID: 21947409 DOI: 10.1007/s00421-011-2177-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 09/09/2011] [Indexed: 11/30/2022]
Abstract
Weighted backpacks are used extensively in recreational and occupational settings, yet their effects on lung mechanics during acute exercise is poorly understood. The purpose of this study was to determine the effects of different backpack weights on lung mechanics and breathing patterns during treadmill walking. Subjects (n = 7, age = 28 ± 6 years), completed two 2.5-min exercise stages for each backpack condition [no backpack (NP), an un-weighted backpack (NW) or a backpack weighing 15, 25 or 35 kg]. A maximal expiratory flow volume curve was generated for each backpack condition and an oesophageal balloon catheter was used to estimate pleural pressure. The 15, 25 and 35 kg backpacks caused a 3, 5 and 8% (P < 0.05) reduction in forced vital capacity compared with the NP condition, respectively. For the same exercise stage, the power of breathing (POB) requirement was higher in the 35 kg backpack compared to NP (32 ± 4.3 vs. 88 ± 9.0 J min(-1), P < 0.05; respectively). Independent of changes in minute ventilation, end-expiratory lung volume decreased as backpack weight increased. As backpack weight increased, there was a concomitant decline in calculated maximal ventilation, a rise in minute ventilation, and a resultant greater utilization of maximal available ventilation. In conclusion, wearing a weighted backpack during an acute bout of exercise altered operational lung volumes; however, adaptive changes in breathing mechanics may have minimized changes in the required POB such that at an iso-ventilation, wearing a backpack weighing up to 35 kg does not increase the POB requirement.
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Affiliation(s)
- Paolo B Dominelli
- School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada.
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12
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Cheung SS, Petersen SR, McLellan TM. Physiological strain and countermeasures with firefighting. Scand J Med Sci Sports 2010; 20 Suppl 3:103-16. [DOI: 10.1111/j.1600-0838.2010.01215.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Kellawan JM, Stuart-Hill LA, Petersen SR. The effects of caffeine during exercise in fire protective ensemble. ERGONOMICS 2009; 52:1445-1454. [PMID: 19851910 DOI: 10.1080/00140130903197453] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
To examine the effects of caffeine during exercise in fire protective ensemble (FPE), 10 healthy males completed 3 x 10 min bouts of treadmill exercise on two separate days. Sixty minutes prior to exercise either 6 mg/kg of caffeine (CAFF) or dextrose placebo (PLA) capsules were ingested (randomly assigned, double blind). End-exercise gastrointestinal temperature (T(gi)) was higher in CAFF compared to PLA (38.80 +/- 0.08 degrees C vs. 38.43 +/- 0.11 degrees C, p < or = 0.01). Ventilation (V(E)) and tidal volume (V(t)) were also significantly higher in CAFF, which resulted in higher consumption of air from the self-contained breathing apparatus. While perceived exertion in the caffeine condition was decreased (p < or = 0.05) compared to placebo, the higher T(gi) values increased calculated physiological strain index in CAFF (p < or = 0.01). Caffeine appears to alter the physiological and psycho-physical responses to exercise in FPE and may influence factors related to work tolerance in firefighting. These findings are relevant to occupations such as firefighting where workers are encapsulated during exposure to heavy physical work and/or environmental heat. The results indicate that workers may be more susceptible to heat-related fatigue, illness or injury with ingestion of significant amounts of caffeine. To the authors' knowledge this is the first study involving humans and exercise to detect an increase in body temperature with caffeine ingestion.
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Mayne JR, Haykowsky MJ, Nelson MD, Hartley TC, Butcher SJ, Jones RL, Petersen SR. Effects of the self-contained breathing apparatus on left-ventricular function at rest and during graded exercise. Appl Physiol Nutr Metab 2009; 34:625-31. [DOI: 10.1139/h09-029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to examine the effects of the self-contained breathing apparatus (SCBA) on left-ventricular (LV) function at rest and during mild- to moderate-intensity exercise, using 2-dimensional echocardiography. Twenty-three healthy male volunteers exercised on a stair-climber at work rates equivalent to 50%, 60%, 70%, and 80% of peak oxygen consumption. Esophageal pressure LV diastolic and systolic cavity areas, and myocardial areas were acquired during the final minute of each stage of exercise. As expected, the esophageal pressure response during SCBA breathing revealed significantly lower (more negative) inspiratory pressures and higher (more positive) expiratory pressures and, consequently, higher pressure swings, than free breathing (FB). End-diastolic cavity area (EDCA) and end-systolic cavity area (ESCA) were lower with the SCBA than with FB. LV contractility was higher (p < 0.05) with the SCBA, which can partially be explained by decreases in end-systolic wall stress. Therefore, the SCBA was found to decrease LV preload during moderate-intensity exercise, but did not negatively affect stroke area because of a similar reduction in ESCA.
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Affiliation(s)
- Jonathan R. Mayne
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
| | - Mark J. Haykowsky
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
| | - Michael D. Nelson
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
| | - Timothy C. Hartley
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
| | - Scott J. Butcher
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
| | - Richard L. Jones
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
| | - Stewart R. Petersen
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK S7N 0W3, Canada
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15
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Nelson MD, Haykowsky MJ, Mayne JR, Jones RL, Petersen SR. Effects of self-contained breathing apparatus on ventricular function during strenuous exercise. J Appl Physiol (1985) 2009; 106:395-402. [DOI: 10.1152/japplphysiol.91193.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to investigate left-ventricular function during strenuous exercise with the self-contained breathing apparatus (SCBA). With the use of two-dimensional echocardiography, images of the left ventricle (LV) were acquired during sustained exercise (3 × 10 min) under two conditions: 1) SCBA, or 2) low resistance breathing valve. Twenty healthy men volunteered for the study, and in each condition subjects wore fire protective equipment. Heart rate, systolic blood pressure, cavity areas during systole and diastole (ESCA and EDCA, respectively), esophageal pressure, ventilation rate, oxygen consumption, perceived physical, thermal and respiratory distress, and core temperature were measured at regular intervals. Urine specific gravity (<1.020 g/ml) and hematological variables were used to infer hydration status. All subjects began both trials in a euhydrated state. No differences were found between conditions for heart rate, systolic blood pressure, ventilation rate, oxygen consumption, perceived distress, or any hematological variables. Peak expiratory esophageal pressure was always higher ( P < 0.05), while EDCA and stroke area (SA) were significantly lower ( P < 0.05) with the SCBA. ESCA, end-systolic transmural pressure (ESTMP), and LV contractility (ESTMP/ESCA) were similar between conditions. Sustained exercise with fire protective equipment resulted in significant reductions in EDCA, ESCA, and SA from the start of exercise, which was associated with a 6.3 ± 0.8% reduction in plasma volume, an increase in core temperature (37.0 ± 0.4 to 38.8 ± 0.3°C), and a significant increase in heart rate (146.9 ± 2.1 to 181.7 ± 2.4 beats/min) throughout exercise. The results from this study support research by others showing that increased intrathoracic pressure reduces LV preload (EDCA); however, the novelty of the present study is that when venous return is compromised by sustained exercise and heat stress, SA cannot be maintained.
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