title: The correlations of glycated hemoglobin and carbohydrate metabolism parameters with heart rate variability in apparently healthy sedentary young male subjects.
abstract: BACKGROUND
  Sedentary lifestyle is a major risk factor for diabetes, cardiovascular and many other age-related diseases. Heart rate variability (HRV) reflects the function of regulatory systems of internal organs and may sensitively indicate early metabolic disturbances. We hypothesize that quantitative and qualitative changes of HRV in young subjects may reflect early metabolic derangements responsible for further development of clinically significant disease.
  
  
  OBJECTIVE
  The aim of our study was to determine whether the parameters of carbohydrate metabolism (fasting blood glucose, HBA1c and surrogate insulin sensitivity/resistance indices) correlate with anthropometric data and HRV.
  
  
  METHODS
  The study group consisted of 30 healthy sedentary male subjects aged 20-40, nonsmokers, mainly office and research employees, medical staff and students. Athletes, actively training more than one hour per week, severely obese and men of physical work were excluded from the study. HRV parameters were derived from short term ECG records (five minutes intervals) in supine position and during orthostatic test. Anthropometric data included height, weight, body mass index (BMI), age and body composition (estimation by bioelectric impedance method). The fasting blood glucose, insulin and C-peptide, homeostatic model assessment (HOMA-IR) index and glycated hemoglobin (HbA1c) were evaluated. Linear correlation coefficient (r) was calculated using Statistica 10.0 software.
  
  
  CONCLUSIONS
  HOMA-IR index correlated positively with body weight, visceral fat and BMI (p=0.047, 0.027 and 0.017 respectively). In supine position pNN50 positively correlated with glucose/insulin ratio (p=0.011) and heart rate with HOMA-IR (p=0.006). In orthostatic test negative correlations of HBA1c with standard deviation, total and low frequency power were determined (p=0.034, 0.400 and 0.403 respectively), which indicates a gradual worsening of functional capacity of cardiovascular system with low-grade increase (under the conventional threshold) of HBA1c.
  
  
  CONCLUSIONS
  In apparently healthy sedentary subjects HRV reduction correlates with the age advancement, subclinical deteriorations of carbohydrate metabolism and excessive fat accumulation.
authors.affiliation: Department of Medicine, Lviv College of Physical Culture, Lviv, Ukraine; Department of Endocrinology, Danylo Halytskyi Lviv National Medical University, Lviv, Ukraine; Department of Internal Medicine #1, Danylo Halytskyi Lviv National Medical University, Lviv, Ukraine. Electronic address: cherkasandriy@yahoo.com.
authors.forename: Andriy
authors.initials: A
authors.lastname: Cherkas
authors.affiliation: Department of Internal Medicine #1, Danylo Halytskyi Lviv National Medical University, Lviv, Ukraine.
authors.forename: Orest
authors.initials: O
authors.lastname: Abrahamovych
authors.affiliation: Department of Pharmaceutical, Organic and Bioorganic Chemistry, Danylo Halytskyi Lviv National Medical University, Lviv, Ukraine.
authors.forename: Sergii
authors.initials: S
authors.lastname: Golota
authors.affiliation: Institute of Cancer Research, Internal Medicine I, Medical University of Vienna, Vienna, Austria.
authors.forename: Armen
authors.initials: A
authors.lastname: Nersesyan
authors.affiliation: Institute of Cancer Research, Internal Medicine I, Medical University of Vienna, Vienna, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Pichler
authors.affiliation: Department of Endocrinology, Danylo Halytskyi Lviv National Medical University, Lviv, Ukraine.
authors.forename: Victoria
authors.initials: V
authors.lastname: Serhiyenko
authors.affiliation: Institute of Cancer Research, Internal Medicine I, Medical University of Vienna, Vienna, Austria.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Knasmüller
authors.affiliation: Laboratory for Oxidative Stress, Rudjer Boskovic Institute, Zagreb, Croatia.
authors.forename: Neven
authors.initials: N
authors.lastname: Zarkovic
authors.affiliation: Department of Cell Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Eckl
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D001835:Body Weight; D050260:Carbohydrate Metabolism / Q000502:physiology*; D004562:Electrocardiography; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise; D006442:Glycated Hemoglobin / Q000032:analysis*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin
keywords: Correlations; Glycated hemoglobin; Heart rate variability; Insulin sensitivity; Sedentary lifestyle