title: Acute effects of interval versus continuous endurance training on pulse wave reflection in healthy young men.
abstract: OBJECTIVE
  Our aim was to investigate the acute and 24-hour (h) effects of high-intensity interval training (HIIT) and moderate continuous training (MCT) on arterial pulse wave reflection, an established marker of arterial stiffness and cardiovascular risk.
  
  
  METHODS
  In a randomized cross-over design, 21 young healthy male participants performed a HIIT or a MCT on separate visits. Before and 5 (t5), 20 (t20), 35 (t35), and 50 (t50) minutes after the acute exercise bouts, the crude augmentation index (AIx) and the AIx at a set heart rate (AIx@75) were analysed by applanation tonometry. Starting 1 h post-exercise, both indices were captured over 24-h with an oscillometric monitoring device.
  
  
  RESULTS
  AIx did not change significantly after MCT but declined progressively after HIIT, reaching significantly lower values compared to MCT at t35 (P = 0.045) and t50 (P = 0.008). AIx@75 increased after both acute exercise types but was higher after HIIT at t5 (P < 0.001), t20 (P < 0.001) and t35 (P = 0.009) compared to MCT. The 24-h follow-up revealed a significant decline in AIx@75 after HIIT (P = 0.007) but not after MCT (P = 0.813).
  
  
  CONCLUSIONS
  Exercise intensity affects pulse wave reflection, with different time courses for AIx and AIx@75 post-exercise. Although initially higher after HIIT, AIx@75 declines in the 24-h recovery period indicating more favourable effects on pulse wave reflection compared to MCT. This may result in substantial positive chronic training effects on arterial stiffness in health and cardiovascular disease.
authors.affiliation: Division of Sports and Exercise Medicine, Department of Sports, Exercise and Health, Medical Faculty, University of Basel, Switzerland. Electronic address: henner.hanssen@unibas.ch.
authors.forename: Henner
authors.initials: H
authors.lastname: Hanssen
authors.affiliation: Division of Sports and Exercise Medicine, Department of Sports, Exercise and Health, Medical Faculty, University of Basel, Switzerland.
authors.forename: Monique
authors.initials: M
authors.lastname: Nussbaumer
authors.affiliation: Division of Sports and Exercise Medicine, Department of Sports, Exercise and Health, Medical Faculty, University of Basel, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Moor
authors.affiliation: Division of Sports and Exercise Medicine, Department of Sports, Exercise and Health, Medical Faculty, University of Basel, Switzerland.
authors.forename: Mareike
authors.initials: M
authors.lastname: Cordes
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, University of Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.affiliation: Division of Sports and Exercise Medicine, Department of Sports, Exercise and Health, Medical Faculty, University of Basel, Switzerland.
authors.forename: Arno
authors.initials: A
authors.lastname: Schmidt-Trucksäss
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D018592:Cross-Over Studies; D064368:Healthy Volunteers; D006339:Heart Rate; D006801:Humans; D008297:Male; D008365:Manometry; D009991:Oscillometry; D010807:Physical Endurance; D011237:Predictive Value of Tests; D011446:Prospective Studies; D063177:Pulse Wave Analysis; D055070:Resistance Training / Q000379:methods*; D013557:Switzerland; D013997:Time Factors; D059289:Vascular Stiffness; D055815:Young Adult
keywords: Arterial stiffness; Augmentation index; Exercise; High intensity interval training; Pulse wave monitoring