Effect of exercise duration on plasma endothelin-1 concentration.
OBJECTIVE
Endothelin-1 (ET-1) is a potent vasoconstricting peptide released mostly from vascular endothelial cells. Isolated exercise sessions of relatively long duration (=or>30 min) have produced increases in plasma ET-1 concentration while shorter exercise sessions usually have not. The purpose of the present study was to verify an effect of exercise duration at a steady work rate on plasma ET-1 concentration.


METHODS
Eleven endurance-trained males (age 27+/-6 years; maximal oxygen consumption--VO2max--56+/-7 mLxkg-1xmin-1, body fat 11+/-5%; mean+/-SD) exercised on a treadmill at 70% VO2max on 2 occasions separated by at least 2 weeks. During a short-duration session, subjects expended approximately 3,360 kJ (60+/-2 min). During a long-duration session, subjects expended approximately 6,300 kJ (112+/-4 min). Six of the subjects performed the 3,360 kJ session before the 6,300 kJ session while the other 5 subjects performed the 6,300 kJ session first.


RESULTS
The short-duration session did not cause plasma ET-1 concentration to change immediately after exercise (0.23+/-0.01 pmolxL-1 before exercise, 0.22+/-0.02 pmolxL-1 after exercise, mean+/-SE). However, 10 of 11 subjects had increased ET-1 after the long-duration session (0.28+/-0.02 pmolxL-1 before exercise, 0.32+/-0.02 pmolxL-1 after exercise, P=0.0004). A treatment-by-time effect was present (P=0.003).


CONCLUSIONS
These results demonstrate an effect of exercise duration on plasma ET-1 concentration. Exercise duration is, therefore, an essential consideration when investigating exercise's effect on ET-1.
Davis
P G
PG
Department of Exercise Science, The University of South Carolina, Columbia, SC, USA. pgdavis@uncg.edu
Ferguson
M A
MA
Alderson
N L
NL
Pate
R R
RR
Bodary
P F
PF
Durstine
J L
JL
D000328:Adult; D019332:Endothelin-1 / Q000097:blood*; D004730:Endothelium, Vascular / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D011446:Prospective Studies; D013997:Time Factors
D019332:Endothelin-1