Left ventricular mechanical limitations to stroke volume in healthy humans during incremental exercise
Author
Stöhr, Eric J.
Gonzalez-Alonso, Jose
Shave, Rob
Date
2011Type
Article
Publisher
American Physiological Society
ISSN
1522-1539
Metadata
Show full item recordAbstract
During incremental exercise, stroke volume (SV) plateaus at 40–50% of maximal exercise capacity. In healthy individuals, left ventricular (LV) twist and untwisting (“LV twist mechanics”) contribute to the generation of SV at rest, but whether the plateau in SV during incremental exercise is related to a blunting in LV twist mechanics remains unknown. To test this hypothesis, nine healthy young males performed continuous and discontinuous incremental supine cycling exercise up to 90% peak power in a randomized order. During both exercise protocols, end-diastolic volume (EDV), end-systolic volume (ESV), and SV reached a plateau at submaximal exercise intensities while heart rate increased continuously. Similar to LV volumes, two-dimensional speckle tracking-derived LV twist and untwisting velocity increased gradually from rest (all P < 0.001) and then leveled off at submaximal intensities. During continuous exercise, LV twist mechanics were linearly related to ESV, SV, heart rate, and cardiac output (all P < 0.01) while the relationship with EDV was exponential. In diastole, the increase in apical untwisting was significantly larger than that of basal untwisting (P < 0.01), emphasizing the importance of dynamic apical function. In conclusion, during incremental exercise, the plateau in LV twist mechanics and their close relationship with SV and cardiac output indicate a mechanical limitation in maximizing LV output during high exercise intensities. However, LV twist mechanics do not appear to be the sole factor limiting LV output, since EDV reaches its maximum before the plateau in LV twist mechanics, suggesting additional limitations in diastolic filling to the heart.
Journal/conference proceeding
American Journal of Physiology: Heart and Circulatory Physiology
Citation
Stöhr, E.J., González-Alonso, J. and Shave, R. (2011) 'Left ventricular mechanical limitations to stroke volume in healthy humans during incremental exercise', American Journal of Physiology-Heart and Circulatory Physiology, 301(2), pp.H478-H487.
Description
This article was published in American Journal of Physiology: Heart and Circulatory Physiology on 1 August 2011, available at
http://dx.doi.org/10.1152/ajpheart.00314.2011
Collections
- Sport Research Groups [1094]
Related items
Showing items related by title, author, subject and abstract.
-
Impaired myocardial function does not explain reduced left ventricular filling and stroke volume at rest or during exercise at high altitude
Stembridge, Mike; Ainslie, Philip; Hughes, Michael G.; Stöhr, Eric J.; Cotter, James D.; Tymko, Michael M.; Day, Trevor A.; Bakker, Akke; Shave, Rob (American Physiological Society, 2015-11-15)Impaired myocardial systolic contraction and diastolic relaxation have been suggested as possible mechanisms contributing to the decreased stroke volume (SV) observed at high altitude (HA). To determine whether intrinsic ... -
Intrinsic ventricular function does not explain reduced stroke volume at rest and during exercise at high altitude
Stembridge, Mike; Ainslie, Philip; Stöhr, Eric J.; Tymko, Michael; Day, Trevor A.; Bakker, Akke; Hughes, Michael G.; Smith, K.J; Willie, C.K.; Lewis, N.C.S.; Shave, Rob (Japanese Society of Physical Fitness and Sports Medicine, 2015-01-25)Introduction: Both impaired systolic dysfunction and myocardial relaxation have previously been advanced as possible mechanisms contributing to decreased stroke volume (SV) at high altitude (HA). To determine whether ... -
Left ventricular twist mechanics during exercise in trained and untrained men
Cooke, Samuel (2016-03-16)Introduction: Left ventricular (LV) twist and untwisting rate (LV twist mechanics) play a crucial role during myocardial deformation. It is suggested that exercise training alters resting LV twist mechanics. However, it ...