title: The impact of exercise-induced core body temperature elevations on coagulation responses.
abstract: OBJECTIVE
  Exercise induces changes in haemostatic parameters and core body temperature (CBT). We aimed to assess whether exercise-induced elevations in CBT induce pro-thrombotic changes in a dose-dependent manner.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  CBT and haemostatic responses were measured in 62 participants of a 15-km road race at baseline and immediately after finishing. As haemostasis assays are routinely performed at 37°C, we corrected the assay temperature for the individual's actual CBT at baseline and finish in a subgroup of n=25.
  
  
  RESULTS
  All subjects (44±11 years, 69% male) completed the race at a speed of 12.1±1.8km/h. CBT increased significantly from 37.6±0.4°C to 39.4±0.8°C (p<0.001). Post-exercise, haemostatic activity was increased, as expressed by accelerated thrombin generation and an attenuated plasmin response. Synchronizing assay temperature to the subjects' actual CBT resulted in additional differences and stronger acceleration of thrombin generation parameters.
  
  
  CONCLUSIONS
  This study demonstrates that exercise induces a prothrombotic state, which might be partially dependent on the magnitude of the exercise-induced CBT rise. Synchronizing the assay temperature to approximate the subject's CBT is essential to obtain more accurate insight in the haemostatic balance during thermoregulatory challenging situations. Finally, this study shows that short-lasting exposure to a CBT of 41.2°C does not result in clinical symptoms of severe coagulation. We therefore hypothesize that prolonged exposure to a high CBT or an individual-specific CBT threshold needs to be exceeded before derailment of the haemostatic balance occurs.
authors.affiliation: Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Physiology, The Netherlands.
authors.forename: Matthijs T W
authors.initials: MTW
authors.lastname: Veltmeijer
authors.affiliation: Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Physiology, The Netherlands; Hartford Hospital, Division of Cardiology, USA.
authors.forename: Thijs M H
authors.initials: TMH
authors.lastname: Eijsvogels
authors.affiliation: Radboud University Medical Center, Department of Laboratory Medicine, Laboratory for Haematology, The Netherlands.
authors.forename: Wideke
authors.initials: W
authors.lastname: Barteling
authors.affiliation: Radboud University Medical Center, Department of Laboratory Medicine, Laboratory for Haematology, The Netherlands.
authors.forename: Kitty
authors.initials: K
authors.lastname: Verbeek-Knobbe
authors.affiliation: Radboud University Medical Center, Department of Laboratory Medicine, Laboratory for Haematology, The Netherlands.
authors.forename: Waander L
authors.initials: WL
authors.lastname: van Heerde
authors.affiliation: Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Physiology, The Netherlands. Electronic address: Maria.Hopman@Radboudumc.nl.
authors.forename: Maria T E
authors.initials: MTE
authors.lastname: Hopman
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012420:Running / Q000502:physiology; D013917:Thrombin / Q000378:metabolism*
chemical_list: D013917:Thrombin; D005341:Fibrinolysin
keywords: Athletes; Haemostasis; Heatstroke; Hyperthermia; Thermoregulation