title: Left atrial functional changes following short-term exercise training.
abstract: BACKGROUND
  Exercise-induced adaptations of the human atria remain understudied, particularly early in the training process. We examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left atrial (LA) systolic and diastolic function, relative to left ventricular (LV) function in young, healthy men, by speckle tracking echocardiography (STE).
  
  
  METHODS
  Fourteen untrained men (mean age = 25 ± 4 years) were randomized to HIT or CMT, and assessed before and after six training sessions over a 12-day period. HIT included 8-12 intervals of cycling for 60 s at 95-100% of maximal aerobic power (VO₂MAX), interspersed by 75 s of cycling at 10 % VO₂MAX. CMT consisted of 90-120 min of cycling at 65% VO₂MAX.
  
  
  RESULTS
  VO₂MAX increased following HIT and CMT by 11.5 and 5.5%, respectively (p < 0.05). Calculated plasma volume expanded 11 % following HIT and 10% following CMT (p < 0.005). Resting LV volumes and ejection fraction were unaltered following training. Peak atrial longitudinal strain increased following HIT (41.8 ± 5.2%-47.1 ± 3.7%, p < 0.01) and CMT (38.5 ± 4.6%-41.7 ± 6.0%, p < 0.01). Atrial systolic strain rate increased following HIT (1.6 ± 0.2%/s-2.0 ± 0.3%/s, p < 0.01) and CMT (1.6 ± 0.2%/s-1.9 ± 0.2%/s, p < 0.01).
  
  
  CONCLUSIONS
  LA function assessed by STE improves rapidly during short-term intensive exercise training.
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, 55 Harbord Street, Toronto, ON, Canada.
authors.forename: Steve
authors.initials: S
authors.lastname: Wright
authors.forename: Sam
authors.initials: S
authors.lastname: Esfandiari
authors.forename: Nader
authors.initials: N
authors.lastname: Elmayergi
authors.forename: Zion
authors.initials: Z
authors.lastname: Sasson
authors.forename: Jack M
authors.initials: JM
authors.lastname: Goodman
mesh_terms: D000328:Adult; D016279:Atrial Function, Left / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D055815:Young Adult