title: Effect of continuous and interval aerobic exercise training on baroreflex sensitivity in heart failure.
abstract: The ability of continuous aerobic exercise training (AET) to increase baroreflex control and cardiac function in heart failure (HF) has been well described, but the comparison between continuous and interval AET on these functions is inconclusive.
  
  
  
  To compare the effects of continuous and interval AET on cardiac function and baroreflex sensitivity (BrS) in an experimental model of HF.
  
  
  
  Rats were divided into the following groups: continuous training (HF-CT), intense interval training (HF-IIT), moderate interval training (HF-MIT), sedentary group (HF-SED), and sham sedentary (SHAM-SED). Animals underwent surgery to induce HF by ligation of the interventricular coronary artery. Six weeks after surgery, AET was started (8weeks, 3sessions/week). Echocardiography studies to assess cardiac function were performed before and after AET. At the end of the training protocols, the BrS index was assessed by stepwise intravenous infusions of sodium nitroprusside and phenylephrine.
  
  
  
  All methods of exercise prevented the HF-induced increase in left ventricular diameter in diastole observed in the HF-SED rats (0.88±0.09 vs. 1.03±0.09cm; P<0.05), but only the HF-CT (28.5±6.3 vs. 39.2±12.7%; P<0.05) and HF-MIT (31.0±8.5 vs. 42.0±10.3%; P<0.05) groups exhibited an increase in ejection fraction. Nevertheless, the HF-CT group was the only group that showed a tachycardia reflex higher than that of the HF-SED group (0.87±0.34 vs. 0.20±0.05bpm/mmHg; P<0.05) and similar to that of the SHAM-SED group (1.04±0.11bpm/mmHg).
  
  
  
  These results suggest that continuous and moderate interval training induced similar improvements in cardiac function but that only continuous training induced higher BrS in HF rats.
authors.affiliation: Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil.
authors.forename: Gustavo Santos
authors.initials: GS
authors.lastname: Masson
authors.affiliation: Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil; Laboratory of Physical Activity and Health Promotion, State University of Rio de Janeiro, Brazil. Electronic address: julipborges@gmail.com.
authors.forename: Juliana Pereira
authors.initials: JP
authors.lastname: Borges
authors.affiliation: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, RJ, Brazil.
authors.forename: Pedro Paulo Soares
authors.initials: PP
authors.lastname: da Silva
authors.affiliation: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, RJ, Brazil.
authors.forename: Antônio Cláudio Lucas
authors.initials: AC
authors.lastname: da Nóbrega
authors.affiliation: Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tibiriçá
authors.affiliation: Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil.
authors.forename: Marcos Adriano
authors.initials: MA
authors.lastname: Lessa
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000503:physiopathology; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D007668:Kidney / Q000503:physiopathology; D008297:Male; D010805:Physical Conditioning, Animal; D017208:Rats, Wistar; D013564:Sympathetic Nervous System / Q000503:physiopathology
keywords: Arterial baroreflex; Cardiac function; Exercise