Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise
Key points Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin. We studied huma...
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| Veröffentlicht in: | The Journal of physiology 2020-04, Vol.598 (8), p.1475-1490 |
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| creator | Dominelli, Paolo B. Wiggins, Chad C. Baker, Sarah E. Shepherd, John R. A. Roberts, Shelly K. Roy, Tuhin K. Curry, Timothy B. Hoyer, James D. Oliveira, Jennifer L. Joyner, Michael J. |
| description | Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.
The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n = 11, n = 8 females) with HAH (P50 = 16 ± 1 mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 = 26 ± 1, n = 14, n = 8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end‐exercise arterial oxygen tension in hypoxia (59 ± 6 vs. 59 ± 9 mmHg for controls and HAH, respectively), the HAH subjects’ oxyhaemoglobin saturation (Sa,O2) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake (V̇O2max) (4 ± 5% vs. 12 ± %, p |
| doi_str_mv | 10.1113/JP279161 |
| format | Article |
| fullrecord | <record><control><sourceid>proquest_pubme</sourceid><recordid>TN_cdi_pubmedcentral_primary_oai_pubmedcentral_nih_gov_7325343</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>2390450618</sourcerecordid><originalsourceid>FETCH-LOGICAL-c4391-d178e7651da7b3d49b258948f50db5e33467a39e1270929c6a70039812f529a73</originalsourceid><addsrcrecordid>eNp1kUtv1TAQRi0EopeCxC9AltiwSfF44jjeIKGKQqtKdFHE0nKSyY2rxL7YCfT--wb64CGxmpHm6GhmPsZegjgCAHx7diG1gQoesQ2UlSm0NviYbYSQskCt4IA9y_lKCEBhzFN2gGAkIsKGfT0N_bhQaInHng9-O3DX9z74ec8HR1PcjrHxgcfA54F4oryLIROfIw8xTfHat9yFjg_73a-erim1PtNz9qR3Y6YXd_WQfTn5cHn8qTj__PH0-P150ZZooOhA16QrBZ3TDXalaaSqTVn3SnSNIsSy0g4NgdTCSNNWTguBpgbZK2mcxkP27ta7W5qJupbCnNxod8lPLu1tdN7-PQl-sNv43WqUCktcBW_uBCl-WyjPdvK5pXF0geKS7fqnSiqDRqzo63_Qq7iksJ63UkaUSlRQ_xa2KeacqH9YBoT9mZa9T2tFX_25_AN4H88KHN0CP_xI-_-K7OXZBaDRgDeHNpxZ</addsrcrecordid><sourcetype>Open Access Repository</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>2390450618</pqid></control><display><type>article</type><title>Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise</title><source>MEDLINE</source><source>Access via Wiley Online Library</source><source>EZB-FREE-00999 freely available EZB journals</source><source>Wiley Online Library (Open Access Collection)</source><source>PubMed Central</source><creator>Dominelli, Paolo B. ; Wiggins, Chad C. ; Baker, Sarah E. ; Shepherd, John R. A. ; Roberts, Shelly K. ; Roy, Tuhin K. ; Curry, Timothy B. ; Hoyer, James D. ; Oliveira, Jennifer L. ; Joyner, Michael J.</creator><creatorcontrib>Dominelli, Paolo B. ; Wiggins, Chad C. ; Baker, Sarah E. ; Shepherd, John R. A. ; Roberts, Shelly K. ; Roy, Tuhin K. ; Curry, Timothy B. ; Hoyer, James D. ; Oliveira, Jennifer L. ; Joyner, Michael J.</creatorcontrib><description>Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.
The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n = 11, n = 8 females) with HAH (P50 = 16 ± 1 mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 = 26 ± 1, n = 14, n = 8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end‐exercise arterial oxygen tension in hypoxia (59 ± 6 vs. 59 ± 9 mmHg for controls and HAH, respectively), the HAH subjects’ oxyhaemoglobin saturation (Sa,O2) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake (V̇O2max) (4 ± 5% vs. 12 ± %, p < 0.001) in hypoxia and the change in V̇O2max between trials was related to the change in SaO2 (r = −0.75, p < 0.0001). Compared to normoxia, the controls’ alveolar‐to‐arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH subjects for both exercise trials. We conclude that HAH attenuates the decline in maximal aerobic capacity and preserves pulmonary gas exchange during acute hypoxic exercise. Our data support the comparative biology literature indicating that HAH is a positive adaptation to acute hypoxia.
Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.</description><identifier>ISSN: 0022-3751</identifier><identifier>EISSN: 1469-7793</identifier><identifier>DOI: 10.1113/JP279161</identifier><identifier>PMID: 31923331</identifier><language>eng</language><publisher>England: Wiley Subscription Services, Inc</publisher><subject>Adaptation ; Aerobic capacity ; Affinity ; Alveoli ; Animals ; Exercise ; Exercise Test ; Female ; Gas exchange ; Gases ; Hemoglobin ; Hemoglobins ; Humans ; Hypoxia ; Lactic acid ; maximal oxygen uptake ; Oxygen ; Oxygen Consumption ; oxygen delivery ; Oxygen tension ; Pulmonary Gas Exchange ; submaximal exercise</subject><ispartof>The Journal of physiology, 2020-04, Vol.598 (8), p.1475-1490</ispartof><rights>2020 The Authors. The Journal of Physiology © 2020 The Physiological Society</rights><rights>2020 The Authors. The Journal of Physiology © 2020 The Physiological Society.</rights><rights>Journal compilation © 2020 The Physiological Society</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c4391-d178e7651da7b3d49b258948f50db5e33467a39e1270929c6a70039812f529a73</citedby><cites>FETCH-LOGICAL-c4391-d178e7651da7b3d49b258948f50db5e33467a39e1270929c6a70039812f529a73</cites><orcidid>0000-0001-5575-4043 ; 0000-0001-7082-9920 ; 0000-0001-7585-9176</orcidid></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC7325343/pdf/$$EPDF$$P50$$Gpubmedcentral$$H</linktopdf><linktohtml>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC7325343/$$EHTML$$P50$$Gpubmedcentral$$H</linktohtml><link.rule.ids>230,314,727,780,784,885,1417,1433,27924,27925,45574,45575,46409,46833,53791,53793</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/31923331$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Dominelli, Paolo B.</creatorcontrib><creatorcontrib>Wiggins, Chad C.</creatorcontrib><creatorcontrib>Baker, Sarah E.</creatorcontrib><creatorcontrib>Shepherd, John R. A.</creatorcontrib><creatorcontrib>Roberts, Shelly K.</creatorcontrib><creatorcontrib>Roy, Tuhin K.</creatorcontrib><creatorcontrib>Curry, Timothy B.</creatorcontrib><creatorcontrib>Hoyer, James D.</creatorcontrib><creatorcontrib>Oliveira, Jennifer L.</creatorcontrib><creatorcontrib>Joyner, Michael J.</creatorcontrib><title>Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise</title><title>The Journal of physiology</title><addtitle>J Physiol</addtitle><description>Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.
The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n = 11, n = 8 females) with HAH (P50 = 16 ± 1 mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 = 26 ± 1, n = 14, n = 8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end‐exercise arterial oxygen tension in hypoxia (59 ± 6 vs. 59 ± 9 mmHg for controls and HAH, respectively), the HAH subjects’ oxyhaemoglobin saturation (Sa,O2) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake (V̇O2max) (4 ± 5% vs. 12 ± %, p < 0.001) in hypoxia and the change in V̇O2max between trials was related to the change in SaO2 (r = −0.75, p < 0.0001). Compared to normoxia, the controls’ alveolar‐to‐arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH subjects for both exercise trials. We conclude that HAH attenuates the decline in maximal aerobic capacity and preserves pulmonary gas exchange during acute hypoxic exercise. Our data support the comparative biology literature indicating that HAH is a positive adaptation to acute hypoxia.
Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.</description><subject>Adaptation</subject><subject>Aerobic capacity</subject><subject>Affinity</subject><subject>Alveoli</subject><subject>Animals</subject><subject>Exercise</subject><subject>Exercise Test</subject><subject>Female</subject><subject>Gas exchange</subject><subject>Gases</subject><subject>Hemoglobin</subject><subject>Hemoglobins</subject><subject>Humans</subject><subject>Hypoxia</subject><subject>Lactic acid</subject><subject>maximal oxygen uptake</subject><subject>Oxygen</subject><subject>Oxygen Consumption</subject><subject>oxygen delivery</subject><subject>Oxygen tension</subject><subject>Pulmonary Gas Exchange</subject><subject>submaximal exercise</subject><issn>0022-3751</issn><issn>1469-7793</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2020</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><recordid>eNp1kUtv1TAQRi0EopeCxC9AltiwSfF44jjeIKGKQqtKdFHE0nKSyY2rxL7YCfT--wb64CGxmpHm6GhmPsZegjgCAHx7diG1gQoesQ2UlSm0NviYbYSQskCt4IA9y_lKCEBhzFN2gGAkIsKGfT0N_bhQaInHng9-O3DX9z74ec8HR1PcjrHxgcfA54F4oryLIROfIw8xTfHat9yFjg_73a-erim1PtNz9qR3Y6YXd_WQfTn5cHn8qTj__PH0-P150ZZooOhA16QrBZ3TDXalaaSqTVn3SnSNIsSy0g4NgdTCSNNWTguBpgbZK2mcxkP27ta7W5qJupbCnNxod8lPLu1tdN7-PQl-sNv43WqUCktcBW_uBCl-WyjPdvK5pXF0geKS7fqnSiqDRqzo63_Qq7iksJ63UkaUSlRQ_xa2KeacqH9YBoT9mZa9T2tFX_25_AN4H88KHN0CP_xI-_-K7OXZBaDRgDeHNpxZ</recordid><startdate>20200401</startdate><enddate>20200401</enddate><creator>Dominelli, Paolo B.</creator><creator>Wiggins, Chad C.</creator><creator>Baker, Sarah E.</creator><creator>Shepherd, John R. A.</creator><creator>Roberts, Shelly K.</creator><creator>Roy, Tuhin K.</creator><creator>Curry, Timothy B.</creator><creator>Hoyer, James D.</creator><creator>Oliveira, Jennifer L.</creator><creator>Joyner, Michael J.</creator><general>Wiley Subscription Services, Inc</general><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7QP</scope><scope>7QR</scope><scope>7TK</scope><scope>7TS</scope><scope>8FD</scope><scope>FR3</scope><scope>P64</scope><scope>7X8</scope><scope>5PM</scope><orcidid>https://orcid.org/0000-0001-5575-4043</orcidid><orcidid>https://orcid.org/0000-0001-7082-9920</orcidid><orcidid>https://orcid.org/0000-0001-7585-9176</orcidid></search><sort><creationdate>20200401</creationdate><title>Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise</title><author>Dominelli, Paolo B. ; Wiggins, Chad C. ; Baker, Sarah E. ; Shepherd, John R. A. ; Roberts, Shelly K. ; Roy, Tuhin K. ; Curry, Timothy B. ; Hoyer, James D. ; Oliveira, Jennifer L. ; Joyner, Michael J.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c4391-d178e7651da7b3d49b258948f50db5e33467a39e1270929c6a70039812f529a73</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2020</creationdate><topic>Adaptation</topic><topic>Aerobic capacity</topic><topic>Affinity</topic><topic>Alveoli</topic><topic>Animals</topic><topic>Exercise</topic><topic>Exercise Test</topic><topic>Female</topic><topic>Gas exchange</topic><topic>Gases</topic><topic>Hemoglobin</topic><topic>Hemoglobins</topic><topic>Humans</topic><topic>Hypoxia</topic><topic>Lactic acid</topic><topic>maximal oxygen uptake</topic><topic>Oxygen</topic><topic>Oxygen Consumption</topic><topic>oxygen delivery</topic><topic>Oxygen tension</topic><topic>Pulmonary Gas Exchange</topic><topic>submaximal exercise</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Dominelli, Paolo B.</creatorcontrib><creatorcontrib>Wiggins, Chad C.</creatorcontrib><creatorcontrib>Baker, Sarah E.</creatorcontrib><creatorcontrib>Shepherd, John R. A.</creatorcontrib><creatorcontrib>Roberts, Shelly K.</creatorcontrib><creatorcontrib>Roy, Tuhin K.</creatorcontrib><creatorcontrib>Curry, Timothy B.</creatorcontrib><creatorcontrib>Hoyer, James D.</creatorcontrib><creatorcontrib>Oliveira, Jennifer L.</creatorcontrib><creatorcontrib>Joyner, Michael J.</creatorcontrib><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>Calcium & Calcified Tissue Abstracts</collection><collection>Chemoreception Abstracts</collection><collection>Neurosciences Abstracts</collection><collection>Physical Education Index</collection><collection>Technology Research Database</collection><collection>Engineering Research Database</collection><collection>Biotechnology and BioEngineering Abstracts</collection><collection>MEDLINE - Academic</collection><collection>PubMed Central (Full Participant titles)</collection><jtitle>The Journal of physiology</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Dominelli, Paolo B.</au><au>Wiggins, Chad C.</au><au>Baker, Sarah E.</au><au>Shepherd, John R. A.</au><au>Roberts, Shelly K.</au><au>Roy, Tuhin K.</au><au>Curry, Timothy B.</au><au>Hoyer, James D.</au><au>Oliveira, Jennifer L.</au><au>Joyner, Michael J.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise</atitle><jtitle>The Journal of physiology</jtitle><addtitle>J Physiol</addtitle><date>2020-04-01</date><risdate>2020</risdate><volume>598</volume><issue>8</issue><spage>1475</spage><epage>1490</epage><pages>1475-1490</pages><issn>0022-3751</issn><eissn>1469-7793</eissn><abstract>Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.
The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n = 11, n = 8 females) with HAH (P50 = 16 ± 1 mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 = 26 ± 1, n = 14, n = 8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end‐exercise arterial oxygen tension in hypoxia (59 ± 6 vs. 59 ± 9 mmHg for controls and HAH, respectively), the HAH subjects’ oxyhaemoglobin saturation (Sa,O2) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake (V̇O2max) (4 ± 5% vs. 12 ± %, p < 0.001) in hypoxia and the change in V̇O2max between trials was related to the change in SaO2 (r = −0.75, p < 0.0001). Compared to normoxia, the controls’ alveolar‐to‐arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH subjects for both exercise trials. We conclude that HAH attenuates the decline in maximal aerobic capacity and preserves pulmonary gas exchange during acute hypoxic exercise. Our data support the comparative biology literature indicating that HAH is a positive adaptation to acute hypoxia.
Key points
Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.
We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.
The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.
Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.
High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.</abstract><cop>England</cop><pub>Wiley Subscription Services, Inc</pub><pmid>31923331</pmid><doi>10.1113/JP279161</doi><tpages>16</tpages><orcidid>https://orcid.org/0000-0001-5575-4043</orcidid><orcidid>https://orcid.org/0000-0001-7082-9920</orcidid><orcidid>https://orcid.org/0000-0001-7585-9176</orcidid><oa>free_for_read</oa></addata></record> |
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| ispartof | The Journal of physiology, 2020-04, Vol.598 (8), p.1475-1490 |
| issn | 0022-3751 1469-7793 |
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| source | MEDLINE; Access via Wiley Online Library; EZB-FREE-00999 freely available EZB journals; Wiley Online Library (Open Access Collection); PubMed Central |
| subjects | Adaptation Aerobic capacity Affinity Alveoli Animals Exercise Exercise Test Female Gas exchange Gases Hemoglobin Hemoglobins Humans Hypoxia Lactic acid maximal oxygen uptake Oxygen Oxygen Consumption oxygen delivery Oxygen tension Pulmonary Gas Exchange submaximal exercise |
| title | Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise |
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