title: Chronobiological changes in arterial blood pressure in participants of the 5th and 6th Czech Antarctic Scientific Expeditions.
abstract: OBJECTIVE
  To evaluate potential changes in arterial blood pressure (ABP) and heart rate (HR) during a 2-month stay in Antarctica, using chronobiological analysis.
  
  
  METHODS
  An observational study performed at Mendel research base, Antarctica, during 2011 and 2012. The studied group consisted of 24 participants of the 5th and 6th Czech Antarctic Scientific Expeditions. Three series of 24-hour ABP monitoring were performed, of these two in Antarctica and one in the Czech Republic. Chronobiological analyses of the data were performed (Halberg Chronobiology Center, Minnesota) using population-mean cosinor. The values of MESOR (Midline Estimating Statistic Of Rhythm), double amplitude and the acrophase were obtained for SBP (Systolic Blood Pressure), DBP (Diastolic Blood Pressure) and HR. These rhythm characteristics were compared between the two locations by parameter tests and by the paired t-test.
  
  
  RESULTS
  On the average, the MESORs of SBP, DBP and HR were significantly higher in Antarctica than in the Czech Republic, as were the double amplitudes of the 12-hour component of SBP and DBP. High prevalence of CHAT (Circadian Hyper-Amplitude-Tension) was detected in Antarctica (8/24 = 33%); only 2 persons had CHAT in the Czech Republic (χ²=3.945, p=0.047).
  
  
  CONCLUSIONS
  A prolonged stay in Antarctica clearly affected certain chronobiological parameters of ABP and HR.
authors: Department of Respiratory Diseases, University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Kristian
authors: K
authors: Brat
authors: Department of Sports Medicine and Rehabilitation, St. Anne's University Hospital and International Clinical Research Center and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Pavel
authors: P
authors: Homolka
authors: Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN, USA.
authors: Germaine
authors: G
authors: Cornélissen
authors: Department of Respiratory Diseases, University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Zdenek
authors: Z
authors: Merta
authors: International Clinical Research Center, St.Anne's University Hospital and Mendel University in Brno, Department of Management, Brno, Czech Republic.
authors: Martin
authors: M
authors: Homolka
authors: Second Department of Internal Medicine, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Ivan
authors: I
authors: Rihacek
authors: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Ostrava and Faculty of Medicine, University of Ostrava, Czech Republic.
authors: Pavel
authors: P
authors: Ševčík
mesh_terms: D000328:Adult; D000864:Antarctic Regions; D062186:Arterial Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D003081:Cold Climate; D018153:Czech Republic; D005101:Expeditions; D005260:Female; D006801:Humans; D008297:Male