title: Influence of third-generation oral contraceptives on the complexity analysis and symbolic dynamics of heart rate variability.
abstract: OBJECTIVE
  To evaluate the influence of oral contraceptives (OCs) containing 20 μg ethinylestradiol (EE) and 150 μg gestodene (GEST) on the autonomic modulation of heart rate (HR) in women.
  
  
  METHODS
  One-hundred and fifty-five women aged 24 ± 2 years were divided into four groups according to their physical activity and the use or not of an OC: active-OC, active-non-OC (NOC), sedentary-OC, and sedentary-NOC. The heart rate was registered in real time based on the electrocardiogram signal for 15 minutes, in the supine-position. The heart rate variability (HRV) was analysed using Shannon's entropy (SE), conditional entropy (complexity index [CInd] and normalised CInd [NCI]), and symbolic analysis (0V%, 1V%, 2LV%, and 2ULV%). For statistical analysis the Kruskal-Wallis test with Dunn post hoc and the Wilcoxon test (p < 0.05 was considered significant) were applied.
  
  
  RESULTS
  Treatment with this COC caused no significant changes in SE, CInd, NCI, or symbolic analysis in either active or sedentary groups. Active groups presented higher values for SE and 2ULV%, and lower values for 0V% when compared to sedentary groups (p < 0.05).
  
  
  CONCLUSIONS
  HRV patterns differed depending on life style; the non-linear method applied was highly reliable for identifying these changes. The use of OCs containing 20 μg EE and 150 μg GEST does not influence HR autonomic modulation.
authors.affiliation: Department of Physiotherapy, Laboratory of Cardiovascular Physiotherapy, Federal University of São Carlos , São Carlos, São Paulo, Brazil. anacristina.silvarebelo@gmail.com
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Rebelo
authors.forename: Nayara
authors.initials: N
authors.lastname: Tamburús
authors.forename: Mariana
authors.initials: M
authors.lastname: Salviati
authors.forename: Vanessa
authors.initials: V
authors.lastname: Celante
authors.forename: Anielle
authors.initials: A
authors.lastname: Takahashi
authors.forename: Marcos Felipe
authors.initials: MF
authors.lastname: de Sá
authors.forename: Aparecida
authors.initials: A
authors.lastname: Catai
authors.forename: Ester
authors.initials: E
authors.lastname: Silva
mesh_terms: D000328:Adult; D003280:Contraceptives, Oral, Synthetic / Q000494:pharmacology*; D004562:Electrocardiography; D004967:Estrogens / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007257:Information Theory; D017711:Nonlinear Dynamics; D009652:Norpregnenes / Q000494:pharmacology*; D057185:Sedentary Behavior; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D003280:Contraceptives, Oral, Synthetic; D004967:Estrogens; D009652:Norpregnenes; C033273:Gestodene; D004997:Ethinyl Estradiol