title: Effect of exercise duration on plasma endothelin-1 concentration.
abstract: 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.
authors.affiliation: Department of Exercise Science, The University of South Carolina, Columbia, SC, USA. pgdavis@uncg.edu
authors.forename: P G
authors.initials: PG
authors.lastname: Davis
authors.forename: M A
authors.initials: MA
authors.lastname: Ferguson
authors.forename: N L
authors.initials: NL
authors.lastname: Alderson
authors.forename: R R
authors.initials: RR
authors.lastname: Pate
authors.forename: P F
authors.initials: PF
authors.lastname: Bodary
authors.forename: J L
authors.initials: JL
authors.lastname: Durstine
mesh_terms: 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
chemical_list: D019332:Endothelin-1