Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness

Lawley, Justin S.; Hearon, Christopher M., Jr; Moralez, Gilbert; Ainslie, Philip N.; Amin, Sachin B.; Hansen, Alexander B.; Mugele, Hendrik; Dawkins, Tony G.; Tymko, Michael M.; Hofstätter, Florian; Simpson, Lydia L.; Gasho, Christopher; Villafuerte, Francisco C.

dc.contributor.author	Hansen, Alexander B.
dc.contributor.author	Amin, Sachin B.
dc.contributor.author	Hofstätter, Florian
dc.contributor.author	Mugele, Hendrik
dc.contributor.author	Simpson, Lydia L.
dc.contributor.author	Gasho, Christopher
dc.contributor.author	Dawkins, Tony G.
dc.contributor.author	Tymko, Michael M.
dc.contributor.author	Ainslie, Philip N.
dc.contributor.author	Villafuerte, Francisco C.
dc.contributor.author	Hearon, Christopher M., Jr
dc.contributor.author	Lawley, Justin S.
dc.contributor.author	Moralez, Gilbert
dc.date.accessioned	2022-06-01T13:53:55Z
dc.date.available	2022-06-01T13:53:55Z
dc.date.issued	2022
dc.identifier.uri	https://hdl.handle.net/20.500.12866/11706
dc.description.abstract	Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS+, n = 7) and without (CMS-, n = 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS+ had a blunted reduction in Δtotal peripheral resistance (CMS-, -10.7 ± 3.8 vs. CMS+, -4.9 ± 4.1 mmHg·L-1·min-1; P = 0.012; d = 1.5) that coincided with a greater Δforearm vasoconstriction (CMS-, -0.2 ± 0.6 vs. CMS+, 1.5 ± 1.3 mmHg·mL-1·min-1; P = 0.008; d = 1.7) and a rise in Δdiastolic blood pressure (CMS-, 14.2 ± 7.2 vs. CMS+, 21.6 ± 4.2 mmHg; P = 0.023; d = 1.2) compared with CMS-. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Δburst incidence was attenuated in CMS+ (P = 0.028; d = 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS-. Furthermore, convective oxygen delivery is maintained during moderate-intensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.NEW & NOTEWORTHY During submaximal exercise, convective oxygen transport is maintained in Andeans suffering from polycythemia. Light intensity exercise elicited similar cardiovascular and autonomic responses compared with healthy Andeans. However, during moderate-intensity exercise, we observed a blunted reduction in total peripheral resistance, which cannot be ascribed to an exaggerated increase in muscle sympathetic nerve activity, indicating possible contributions from other neural and/or nonneural mechanisms.	en_US
dc.language.iso	eng
dc.publisher	American Physiological Society
dc.relation.ispartofseries	American Journal of Physiology - Heart and Circulatory Physiology
dc.rights	info:eu-repo/semantics/restrictedAccess
dc.subject	Autonomic function	en_US
dc.subject	Chronic mountain sickness	en_US
dc.subject	Convective oxygen delivery	en_US
dc.subject	Exercise hemodynamics	en_US
dc.subject	Muscle sympathetic nerve activity	en_US
dc.title	Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness	en_US
dc.type	info:eu-repo/semantics/article
dc.identifier.doi	https://doi.org/10.1152/ajpheart.00555.2021
dc.subject.ocde	https://purl.org/pe-repo/ocde/ford#3.01.08
dc.subject.ocde	https://purl.org/pe-repo/ocde/ford#3.02.04
dc.relation.issn	1522-1539