title: Greater autonomic modulation during post-exercise hypotension following high-intensity interval exercise in endurance-trained men and women.
abstract: OBJECTIVE
  An acute reduction in blood pressure observed after a single bout of exercise is termed post-exercise hypotension (PEH). In contrast to moderate intensity aerobic exercise, little is known about the PEH response following high-intensity interval exercise. The present purpose is to assess how sex and training status impact PEH following high-intensity interval exercise.
  
  
  METHODS
  Cardiac volumes and function via echocardiography were measured in 40 normotensive, endurance-trained (ET) and normally active (NA) men and women (Age ± SD = 30.5 ± 5.7) following high-intensity interval cycle exercise. Continuous measurements of ECG and beat-by-beat blood pressure were collected before and 30 min post-exercise for determination of cardiovagal baroreflex function (BRS and αLF), spectral analysis of heart rate and systolic blood pressure (SBP LF).
  
  
  RESULTS
  Post-exercise systolic BP was significantly reduced from baseline, occurring to a greater degree in ET compared with NA (-12.9 vs. -5.3 mmHg, P = 0.008), while mean arterial pressure was similarly reduced in all groups (-4.6 mmHg, P = 0.003). Despite reduced SVI and TPRI, CI was increased post-exercise (P < 0.01). ET experienced a greater decrease in αLF (P = 0.037) and increase in SBP LF (P = 0.017) than NA. Lean body mass was a significant predictor of change in SBP LF (Std. β = 0.735, P = 0.008).
  
  
  CONCLUSIONS
  These results characterize greater depressions in cardiovagal baroreflex function, and increased sympathetic activity, following vigorous exercise in endurance-trained individuals compared with normally active participants. This heightened sympathovagal balance after high-intensity exercise may be a compensatory mechanism in response to greater peripheral blood flow demands following vigorous exercise.
authors.affiliation: Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Rm. 205, Unit II Osborne Centre, 6108 Thunderbird Blvd, Vancouver, BC, V6T 1Z3, Canada, a.cote@alumni.ubc.ca.
authors.forename: Anita T
authors.initials: AT
authors.lastname: Cote
authors.forename: Shannon S D
authors.initials: SS
authors.lastname: Bredin
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Phillips
authors.forename: Michael S
authors.initials: MS
authors.lastname: Koehle
authors.forename: Darren E R
authors.initials: DE
authors.lastname: Warburton
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D017704:Baroreflex; D001794:Blood Pressure; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D057774:Post-Exercise Hypotension / Q000503:physiopathology*; D012737:Sex Factors