Respiratory Limitations to Exercise (Essay Sample)

Respiratory Limitations to Exercise
“The lung is overbuilt for the demands of exercise”
Traditionally, a view has been held that “the lung is overbuilt for the demands of exercise.” The belief was based on the capacity of the liver to meet its maximum metabolic requirements during exercise and the respiratory system’s ability to provide for gaseous exchange during maximal exercise ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"GDNHK7ql","properties":{"formattedCitation":"(Olfert, 2016)","plainCitation":"(Olfert, 2016)","noteIndex":0},"citationItems":[{"id":3164,"uris":["http://zotero.org/users/4013864/items/RLY98QVL"],"uri":["http://zotero.org/users/4013864/items/RLY98QVL"],"itemData":{"id":3164,"type":"article-journal","container-title":"The Journal of Physiology","DOI":"10.1113/JP272370","ISSN":"0022-3751","issue":"18","journalAbbreviation":"J Physiol","note":"PMID: 27629073\nPMCID: PMC5023719","page":"5037-5038","source":"PubMed Central","title":"Exercise and the lungs: nature or nurture?","title-short":"Exercise and the lungs","URL":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023719/","volume":"594","author":[{"family":"Olfert","given":"I. Mark"}],"accessed":{"date-parts":[["2021",1,13]]},"issued":{"date-parts":[["2016",9,15]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Olfert, 2016). However, the perception is incapacitated by the fact that highly fit and experienced athletes can still encounter impairments in gaseous exchange especially towards the peak aerobic capacity as the exercise intensity increases, which often leads to a condition referred to as exercise-induced arterial hypoxemia ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"uDWxbYTR","properties":{"formattedCitation":"(Olfert, 2016)","plainCitation":"(Olfert, 2016)","noteIndex":0},"citationItems":[{"id":3164,"uris":["http://zotero.org/users/4013864/items/RLY98QVL"],"uri":["http://zotero.org/users/4013864/items/RLY98QVL"],"itemData":{"id":3164,"type":"article-journal","container-title":"The Journal of Physiology","DOI":"10.1113/JP272370","ISSN":"0022-3751","issue":"18","journalAbbreviation":"J Physiol","note":"PMID: 27629073\nPMCID: PMC5023719","page":"5037-5038","source":"PubMed Central","title":"Exercise and the lungs: nature or nurture?","title-short":"Exercise and the lungs","URL":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023719/","volume":"594","author":[{"family":"Olfert","given":"I. Mark"}],"accessed":{"date-parts":[["2021",1,13]]},"issued":{"date-parts":[["2016",9,15]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Olfert, 2016). The occurrence is synonymous in all mammals and is deemed to demystify the belief that the lung is priorly overbuilt for the demands of exercise.
During maximal aerobic exercise, some of the experienced and trained athletes commonly experience episodes of arterial hypoxaemia. According to ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"viSm1Gos","properties":{"formattedCitation":"(Phillips & Stickland, 2019)","plainCitation":"(Phillips & Stickland, 2019)","noteIndex":0},"citationItems":[{"id":3167,"uris":["http://zotero.org/users/4013864/items/CUFJNK7E"],"uri":["http://zotero.org/users/4013864/items/CUFJNK7E"],"itemData":{"id":3167,"type":"article-journal","abstract":"Although the lungs are traditionally considered to be overbuilt for exercise in healthy individuals, respiratory-related limitations to exercise have been identified. First, during exercise most humans develop an impairment in pulmonary gas-exchange, which can lead to a reduction in maximal oxygen uptake (V˙O2max). Second, ventilatory constraint, specifically expiratory flow limitation and dynamic hyperinflation, have been shown to impair exercise performance. Lastly, respiratory muscle fatigue and/or large increases in work of breathing can negatively affect exercise performance by triggering a sympathetic-mediated increase in vasoconstriction of the locomotor vasculature, which decreases locomotor muscle O2 delivery. In this review, we provide a brief overview of these limitations to exercise, and examine recent advances in the field. In addition, relevant new work around sex-differences in these limitations to exercise will be examined.","collection-title":"Exercise Physiology","container-title":"Current Opinion in Physiology","DOI":"10.1016/j.cophys.2019.05.012","ISSN":"2468-8673","journalAbbreviation":"Current Opinion in Physiology","language":"en","page":"173-179","source":"ScienceDirect","title":"Respiratory limitations to exercise in health: a brief review","title-short":"Respiratory limitations to exercise in health","URL":"http://www.sciencedirect.com/science/article/pii/S2468867319300987","volume":"10","author":[{"family":"Phillips","given":"Devin B"},{"family":"Stickland","given":"Michael K"}],"accessed":{"date-parts":[["2021",1,13]]},"issued":{"date-parts":[["2019",8,1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} Phillips & Stickland (2019), there is an observed impairment in pulmonary gaseous exchange evidenced by an increase in the alveolar-arterial difference, which is mainly responsible for exercise-induced arterial hypoxaemia. The author also outlines that exercise induced arterial hypoxaemia (EIAH) may reduce the maximum oxygen uptake and hence, its contribution towards exercise limitation. However, other factors have also been discussed in relation to causes of EIAH among well-trained athletes during intensive exercise. For instance, ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"yyeQQWsi","properties":{"formattedCitation":"(Olfert, 2016)","plainCitation":"(Olfert, 2016)","dontUpdate":true,"noteIndex":0},"citationItems":[{"id":3164,"uris":["http://zotero.org/users/4013864/items/RLY98QVL"],"uri":["http://zotero.org/users/4013864/items/RLY98QVL"],"itemData":{"id":3164,"type":"article-journal","container-title":"The Journal of Physiology","DOI":"10.1113/JP272370","ISSN":"0022-3751","issue":"18","journalAbbreviation":"J Physiol","note":"PMID: 27629073\nPMCID: PMC5023719","page":"5037-5038","source":"PubMed Central","title":"Exercise and the lungs: nature or nurture?","title-short":"Exercise and the lungs","URL":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023719/","volume":"594","author":[{"family":"Olfert","given":"I. Mark"}],"accessed":{"date-parts":[["2021",1,13]]},"issued":{"date-parts":[["2016",9,15]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} Olfert (2016) explains that lung size is an important factor that influences susceptibility to EIAH, despite the fact that its is common among athletes with high V02max. Thus, the occurrence of EIAH is dependent upon the “combination of lung size and strongly the aerobic/metabolic engine is developed by training in any individual…,” which would then determine whether an impairment in gas exchange or EIAH would occur ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"lCK5O66O","properties":{"formattedCitation":"(Phillips & Stickland, 2019, p. 5038)","plainCitation":"(Phillips & Stickland, 2019, p. 5038)","noteIndex":0},"citationItems":[{"id":3167,"uris":["http://zotero.org/users/4013864/items/CUFJNK7E"],"uri":["http://zotero.org/users/4013864/items/CUFJNK7E"],"itemData":{"id":3167,"type":"article-journal","abstract":"Although the lungs are traditionally considered to be overbuilt for exercise in healthy individuals, respiratory-related limitations to exercise have been identified. First, during exercise most humans develop an impairment in pulmonary gas-exchange, which can lead to a reduction in maximal oxygen uptake (V˙O2max). Second, ventilatory constraint, specifically expiratory flow limitation and dynamic hyperinflation, have been shown to impair exercise performance. Lastly, respiratory muscle fatigue and/or large increases in work of breathing can negatively affect exercise performance by triggering a sympathetic-mediated increase in vasoconstriction of the locomotor vasculature, which decreases locomotor muscle O2 delivery. In this review, we provide a brief overview of these limitations to exercise, and examine recent advances in the field. In addition, relevant new work around sex-differences in these limitations to exercise will be examined.","collection-title":"Exercise Physiology","container-title":"Current Opinion in Physiology","DOI":"10.1016/j.cophys.2019.05.012","ISSN":"2468-8673","journalAbbreviation":"Current Opinion in Physiology","language":"en","page":"173-179","source":"ScienceDirect","title":"Respiratory limitations to exercise in health: a brief review","title-short":"Respiratory limitations to exercise in health","URL":"http://www.sciencedirect.com/science/article/pii/S2468867319300987","volume":"10","author":[{"family":"Phillips","given":"Devin B"},{"family":"Stickland","given":"Michael K"}],"accessed":{"date-parts":[["2021",1,13]]},"issued":{"date-parts":[["2019",8,1]]}},"locator":"5038","label":"page"}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Phillips & Stickland, 2019, p. 5038).
Excessive ventilatory demand during intensive exercise, together with an increase in intra-thoracic and abdominal pressures have various effects on the endurance trained subjects. First, individuals often experience hyperinflation that enables an increase in the flow of rate while shortening inspiratory muscles to their optimal length ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"2TZhaUAD","properties":{"formattedCitation":"(Dempsey et al., 2020)","plainCitation":"(Dempsey et al., 2020)","noteIndex":0},"citationItems":[{"id":3170,"uris":["http://zotero.org/users/4013864/items/YVKVRSG4"],"uri":["http://zotero.org/users/4013864/items/YVKVRSG4"],"itemData":{"id":3170,"type":"article-journal","abst...