title: Caffeine and physical training: effects on cardiac morphology and cardiovascular response.
abstract: OBJECTIVE
  to analyze the morphological structure of cardiac, blood pressure (BP), heart rate (HR) and heart rate variability (HRV) of rats subjected to physical training with supplementation of caffeine.
  
  
  METHODS
  60 rats were divided into 4 groups: control (CO), control with caffeine (CAF), trained control (TRE) and trained with caffeine (TCAF). All trained groups underwent 4 weeks of swimming, and all caffeine groups were supplemented by voluntary ingestion of caffeine diluted in drinking water.
  
  
  RESULTS
  there were no changes to BP and HR between groups. Regarding HRV, there was a decrease in LFnorm (low frequency) and LF/HF ratio (low and high frequency) in TCAF and CAF compared to group (p<0.02 and p<0.03, respectively). An increase occurred in CAF compared to the CO in the component LFnorm (p<0.05). The results also showed an increase in the relative weight of heart in the TRE (p<0.04) and TCAF (p<0.03) compared to CO.
  
  
  CONCLUSIONS
  caffeine did not modify the hemodynamic responses. However, physical training resulted in a decrease in sympathetic response and an increase in relative heart weight.
authors.affiliation: Associate Postgraduate Program in Physical Education, UEM/UEL, Londrina, PR, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Ruiz
authors.affiliation: Department of Histology, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Solange de Paula
authors.initials: Sde P
authors.lastname: Ramos
authors.affiliation: Department of Physiology, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Marli Martins
authors.initials: MM
authors.lastname: Pinge
authors.affiliation: Associate Postgraduate Program in Physical Education, UEM/UEL, Londrina, PR, Brazil.
authors.forename: Solange Franzói de
authors.initials: SF
authors.lastname: Moraes
authors.affiliation: Associate Postgraduate Program in Physical Education, UEM/UEL, Londrina, PR, Brazil.
authors.forename: Marcos
authors.initials: M
authors.lastname: Polito
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D006321:Heart / Q000033:anatomy & histology / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017208:Rats, Wistar; D013550:Swimming / Q000502:physiology
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine