Details
| Original language | English |
|---|---|
| Article number | e14433 |
| Journal | Physiological Reports |
| Volume | 8 |
| Issue number | 11 |
| Publication status | Published - 1 Jun 2020 |
| Externally published | Yes |
Abstract
Dehydration accrued during intense prolonged whole-body exercise in the heat compromises peripheral blood flow and cardiac output ((Formula presented.)). A markedly reduced stroke volume (SV) is a key feature of the dehydration-induced cardiovascular strain, but whether the lower output of the heart is mediated by peripheral or cardiac factors remains unknown. Therefore, we repeatedly quantified left ventricular (LV) volumes, LV mechanics (LV twist, a marker of systolic muscle function, and LV untwisting rate, an independent marker of LV muscle relaxation), left intra-ventricular pressure gradients, blood volume and peripheral blood flow during 2 hr of cycling in the heat with and without dehydration (DEH: 4.0 ± 0.2% body mass loss and EUH: euhydration control, respectively) in eight participants (three females and five males). While brachial and carotid blood flow, blood volume, SV, LV end-diastolic volume (LVEDV), cardiac filling time, systemic vascular conductance and (Formula presented.) were reduced in DEH compared to EUH after 2 hr, LV twist and untwisting rate tended to be higher (p =.09 and.06, respectively) and intra-ventricular pressure gradients were not different between the two conditions (p =.22). Furthermore, LVEDV in DEH correlated strongly with blood volume (r =.995, p <.01), head and forearms beat volume (r =.98, p <.05), and diastolic LV filling time (r =.98, p <.05). These findings suggest that the decline in SV underpinning the blunted (Formula presented.) with exercise-induced dehydration is caused by compromised LV filling and venous return, but not intrinsic systolic or diastolic LV function.
Keywords
- blood flow, intraventricular pressure gradients, left ventricular volumes, twist and untwisting rate
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Physiology
- Medicine(all)
- Physiology (medical)
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In: Physiological Reports, Vol. 8, No. 11, e14433, 01.06.2020.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Dehydration reduces stroke volume and cardiac output during exercise because of impaired cardiac filling and venous return, not left ventricular function
AU - Watanabe, Kazuhito
AU - Stöhr, Eric J.
AU - Akiyama, Koichi
AU - Watanabe, Sumie
AU - González-Alonso, José
PY - 2020/6/1
Y1 - 2020/6/1
N2 - Dehydration accrued during intense prolonged whole-body exercise in the heat compromises peripheral blood flow and cardiac output ((Formula presented.)). A markedly reduced stroke volume (SV) is a key feature of the dehydration-induced cardiovascular strain, but whether the lower output of the heart is mediated by peripheral or cardiac factors remains unknown. Therefore, we repeatedly quantified left ventricular (LV) volumes, LV mechanics (LV twist, a marker of systolic muscle function, and LV untwisting rate, an independent marker of LV muscle relaxation), left intra-ventricular pressure gradients, blood volume and peripheral blood flow during 2 hr of cycling in the heat with and without dehydration (DEH: 4.0 ± 0.2% body mass loss and EUH: euhydration control, respectively) in eight participants (three females and five males). While brachial and carotid blood flow, blood volume, SV, LV end-diastolic volume (LVEDV), cardiac filling time, systemic vascular conductance and (Formula presented.) were reduced in DEH compared to EUH after 2 hr, LV twist and untwisting rate tended to be higher (p =.09 and.06, respectively) and intra-ventricular pressure gradients were not different between the two conditions (p =.22). Furthermore, LVEDV in DEH correlated strongly with blood volume (r =.995, p <.01), head and forearms beat volume (r =.98, p <.05), and diastolic LV filling time (r =.98, p <.05). These findings suggest that the decline in SV underpinning the blunted (Formula presented.) with exercise-induced dehydration is caused by compromised LV filling and venous return, but not intrinsic systolic or diastolic LV function.
AB - Dehydration accrued during intense prolonged whole-body exercise in the heat compromises peripheral blood flow and cardiac output ((Formula presented.)). A markedly reduced stroke volume (SV) is a key feature of the dehydration-induced cardiovascular strain, but whether the lower output of the heart is mediated by peripheral or cardiac factors remains unknown. Therefore, we repeatedly quantified left ventricular (LV) volumes, LV mechanics (LV twist, a marker of systolic muscle function, and LV untwisting rate, an independent marker of LV muscle relaxation), left intra-ventricular pressure gradients, blood volume and peripheral blood flow during 2 hr of cycling in the heat with and without dehydration (DEH: 4.0 ± 0.2% body mass loss and EUH: euhydration control, respectively) in eight participants (three females and five males). While brachial and carotid blood flow, blood volume, SV, LV end-diastolic volume (LVEDV), cardiac filling time, systemic vascular conductance and (Formula presented.) were reduced in DEH compared to EUH after 2 hr, LV twist and untwisting rate tended to be higher (p =.09 and.06, respectively) and intra-ventricular pressure gradients were not different between the two conditions (p =.22). Furthermore, LVEDV in DEH correlated strongly with blood volume (r =.995, p <.01), head and forearms beat volume (r =.98, p <.05), and diastolic LV filling time (r =.98, p <.05). These findings suggest that the decline in SV underpinning the blunted (Formula presented.) with exercise-induced dehydration is caused by compromised LV filling and venous return, but not intrinsic systolic or diastolic LV function.
KW - blood flow
KW - intraventricular pressure gradients
KW - left ventricular volumes
KW - twist and untwisting rate
UR - http://www.scopus.com/inward/record.url?scp=85086570573&partnerID=8YFLogxK
U2 - 10.14814/phy2.14433
DO - 10.14814/phy2.14433
M3 - Article
C2 - 32538549
AN - SCOPUS:85086570573
VL - 8
JO - Physiological Reports
JF - Physiological Reports
IS - 11
M1 - e14433
ER -