Details
| Original language | English |
|---|---|
| Pages (from-to) | 891-897 |
| Number of pages | 7 |
| Journal | Journal of applied physiology |
| Volume | 111 |
| Issue number | 3 |
| Early online date | 1 Sept 2011 |
| Publication status | Published - 1 Sept 2011 |
| Externally published | Yes |
Abstract
The purpose of this study was to determine whether the reduction in stroke volume (SV), previously shown to occur with dehydration and increases in internal body temperatures during prolonged exercise, is caused by a reduction in left ventricular (LV) function, as indicated by LV volumes, strain, and twist ("LV mechanics"). Eight healthy men [age: 20 ± 2, maximal oxygen uptake (VO 2max): 58 ± 7 ml kg -1min -1] completed two, 1-h bouts of cycling in the heat (35°C, 50% peak power) without fluid replacement, resulting in 2% and 3.5% dehydration, respectively. Conventional and two-dimensional speckle-tracking echocardiography was used to determine LV volumes, strain, and twist at rest and during one-legged knee-extensor exercise at baseline, both levels of dehydration, and following rehydration. Progressive dehydration caused a significant reduction in end-diastolic volume (EDV) and SV at rest and during one-legged knee-extensor exercise (rest: δ- 33 ± 14 and δ- 21 ± 14 ml, respectively; exercise: δ- 30 ± 10 and δ- 22 ± 9 ml, respectively, during 3.5% dehydration). In contrast to the marked decline in EDV and SV, systolic and diastolic LV mechanics were either maintained or even enhanced with dehydration at rest and during knee-extensor exercise. We conclude that dehydration-induced reductions in SV at rest and during exercise are the result of reduced LV filling, as reflected by the decline in EDV. The concomitant maintenance of LV mechanics suggests that the decrease in LV filling, and consequently ejection, is likely caused by the reduction in blood volume and/or diminished filling time rather than impaired LV function.
Keywords
- Diastole, Hypohydration, Torsion, Untwisting
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Physiology
- Medicine(all)
- Physiology (medical)
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Journal of applied physiology, Vol. 111, No. 3, 01.09.2011, p. 891-897.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Dehydration reduces left ventricular filling at rest and during exercise independent of twist mechanics
AU - Stöhr, Eric J.
AU - González-Alonso, José
AU - Pearson, James
AU - Low, David A.
AU - Ali, Leena
AU - Barke, Horace
AU - Shave, Rob
PY - 2011/9/1
Y1 - 2011/9/1
N2 - The purpose of this study was to determine whether the reduction in stroke volume (SV), previously shown to occur with dehydration and increases in internal body temperatures during prolonged exercise, is caused by a reduction in left ventricular (LV) function, as indicated by LV volumes, strain, and twist ("LV mechanics"). Eight healthy men [age: 20 ± 2, maximal oxygen uptake (VO 2max): 58 ± 7 ml kg -1min -1] completed two, 1-h bouts of cycling in the heat (35°C, 50% peak power) without fluid replacement, resulting in 2% and 3.5% dehydration, respectively. Conventional and two-dimensional speckle-tracking echocardiography was used to determine LV volumes, strain, and twist at rest and during one-legged knee-extensor exercise at baseline, both levels of dehydration, and following rehydration. Progressive dehydration caused a significant reduction in end-diastolic volume (EDV) and SV at rest and during one-legged knee-extensor exercise (rest: δ- 33 ± 14 and δ- 21 ± 14 ml, respectively; exercise: δ- 30 ± 10 and δ- 22 ± 9 ml, respectively, during 3.5% dehydration). In contrast to the marked decline in EDV and SV, systolic and diastolic LV mechanics were either maintained or even enhanced with dehydration at rest and during knee-extensor exercise. We conclude that dehydration-induced reductions in SV at rest and during exercise are the result of reduced LV filling, as reflected by the decline in EDV. The concomitant maintenance of LV mechanics suggests that the decrease in LV filling, and consequently ejection, is likely caused by the reduction in blood volume and/or diminished filling time rather than impaired LV function.
AB - The purpose of this study was to determine whether the reduction in stroke volume (SV), previously shown to occur with dehydration and increases in internal body temperatures during prolonged exercise, is caused by a reduction in left ventricular (LV) function, as indicated by LV volumes, strain, and twist ("LV mechanics"). Eight healthy men [age: 20 ± 2, maximal oxygen uptake (VO 2max): 58 ± 7 ml kg -1min -1] completed two, 1-h bouts of cycling in the heat (35°C, 50% peak power) without fluid replacement, resulting in 2% and 3.5% dehydration, respectively. Conventional and two-dimensional speckle-tracking echocardiography was used to determine LV volumes, strain, and twist at rest and during one-legged knee-extensor exercise at baseline, both levels of dehydration, and following rehydration. Progressive dehydration caused a significant reduction in end-diastolic volume (EDV) and SV at rest and during one-legged knee-extensor exercise (rest: δ- 33 ± 14 and δ- 21 ± 14 ml, respectively; exercise: δ- 30 ± 10 and δ- 22 ± 9 ml, respectively, during 3.5% dehydration). In contrast to the marked decline in EDV and SV, systolic and diastolic LV mechanics were either maintained or even enhanced with dehydration at rest and during knee-extensor exercise. We conclude that dehydration-induced reductions in SV at rest and during exercise are the result of reduced LV filling, as reflected by the decline in EDV. The concomitant maintenance of LV mechanics suggests that the decrease in LV filling, and consequently ejection, is likely caused by the reduction in blood volume and/or diminished filling time rather than impaired LV function.
KW - Diastole
KW - Hypohydration
KW - Torsion
KW - Untwisting
UR - http://www.scopus.com/inward/record.url?scp=80053024638&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.00528.2011
DO - 10.1152/japplphysiol.00528.2011
M3 - Article
C2 - 21700893
AN - SCOPUS:80053024638
VL - 111
SP - 891
EP - 897
JO - Journal of applied physiology
JF - Journal of applied physiology
SN - 8750-7587
IS - 3
ER -