Open Access Open Badges Research

Influence of type 2 diabetes on symbolic analysis and complexity of heart rate variability in men

Sílvia CG Moura-Tonello1, Anielle CM Takahashi1, Cristina O Francisco1, Sérgio LB Lopes2, Adriano M Del Vale1, Audrey Borghi-Silva1, Angela MO Leal2, Nicola Montano3, Alberto Porta4 and Aparecida M Catai1*

  • * Corresponding author: Aparecida M Catai

  • † Equal contributors

Author Affiliations

1 Physiotherapy Department, Cardiovascular Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of São Carlos, São Paulo, Brazil

2 Department of Medicine, Federal University of São Carlos, São Paulo, Brazil

3 Department of Clinical Sciences, Internal Medicine II, L. Sacco Hospital, University of Milan, Milan, Italy

4 Department of Technologies for Health, Galeazzi Orthopaedic Institute, University of Milan, Milan, Italy

For all author emails, please log on.

Diabetology & Metabolic Syndrome 2014, 6:13  doi:10.1186/1758-5996-6-13

Published: 1 February 2014



Individuals with diabetes may develop cardiac autonomic dysfunction that may be evaluated by heart rate variability (HRV). The aim was evaluated heart rate variability (HRV) of individuals with type 2 diabetes, without cardiovascular autonomic neuropathy (CAN), in response to active postural maneuver by means of nonlinear analysis (symbolic analysis, Shannon and conditional entropy) and correlate HRV parameters between them, glycated hemoglobin and diabetes duration.


Nineteen men with type 2 diabetes without CAN (T2D) and nineteen healthy men (CG), age-range from 40 to 60 years were studied. We assessed HRV in supine and orthostatic position using symbolic analysis (0V%, 1V%, 2LV% and 2UV%), Shannon and conditional entropy (SE and NCI).


In supine position T2D presented higher sympathetic modulation (0V%) than CG. However, there was not any difference between groups for indexes of complexity (SE and NCI). Furthermore, T2D presented a preserved response of cardiac autonomic modulation after active postural maneuver.


The present study showed that individuals with type 2 diabetes without CAN presented higher cardiac sympathetic modulation. However, the complexity of HRV was not influenced by imbalance of the autonomic modulation in individuals with type 2 diabetes. In addition, the response of autonomic nervous system in the heart remains preserved after active postural maneuver in individuals with type 2 diabetes, possibly due to the lack of CAN in this group.

Heart rate variability; Type 2 diabetes mellitus; Symbolic analysis; Shannon entropy and conditional entropy