title: Disgust stimuli reduce heart rate but do not contribute to vasovagal symptoms.
abstract: OBJECTIVE
  The vasovagal response demonstrates a unique form of stress response, common in medical settings yet provoked by a variety of blood-injury-injection stimuli. This study aimed to better understand the psychophysiological mechanisms of the vasovagal response..
  
  
  METHODS
  16 undergraduates with and 42 without a self-reported history of fainting watched five 3-5 min videos with different emotional content. One documentary clip (Neutral condition) described a campus environmental project while another (Blood/Injury) depicted portions of an open heart surgery. Three additional clips were also used, including Medical, Threat, and Contamination stimuli. Vasovagal symptoms and physiological variables were assessed during each video.
  
  
  RESULTS
  As predicted, while the disgust-related stimuli (Blood/Injury, Medical, Contamination) were associated with generally lower heart rate, the Blood/Injury video produced the highest symptoms and the only significant difference between previous fainters and non-fainters. The physiological measures also revealed that participants with a fainting history experienced higher stroke volume and lower systolic blood pressure throughout, as well as several main effects of video.
  
  
  CONCLUSIONS
  An additional decrease in systolic blood pressure and respiration produced by watching the Blood/Injury video may have been sufficient to trigger symptoms in some, though results also suggest that systemic variables do not entirely explain susceptibility to symptoms. More careful evaluation of regional blood flow may be required.
  
  
  CONCLUSIONS
  Participants who had previously experienced strong vasovagal responses displayed what appeared to be an anticipatory response to the Blood/Injury video. Finally, disgust stimuli may reduce heart rate but do not appear to contribute to vasovagal symptoms.
authors: Wolfson College, University of Cambridge, Cambridge, CB3 9BB, United Kingdom. Electronic address: pg443@medschl.cam.ac.uk.
authors: Philippe T
authors: PT
authors: Gilchrist
authors: Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Dr. Penfield Ave, Montreal, Quebec, H3A 1B, Canada.
authors: Tudor
authors: T
authors: Vrinceanu
authors: Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Dr. Penfield Ave, Montreal, Quebec, H3A 1B, Canada.
authors: Sophie
authors: S
authors: Béland
authors: Montreal Behavioural Medicine Centre and Research Centre, Hôpital du Sacré-Coeur de Montréal -a University of Montreal Affiliated Hospital, Montreal, H4J 1C5, Canada; Department of Exercise Science, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B 1R6, Canada.
authors: Simon L
authors: SL
authors: Bacon
authors: Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Dr. Penfield Ave, Montreal, Quebec, H3A 1B, Canada.
authors: Blaine
authors: B
authors: Ditto
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D004562:Electrocardiography; D004644:Emotions / Q000502:physiology*; D005239:Fear / Q000523:psychology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011569:Psychiatric Status Rating Scales; D012039:Regional Blood Flow / Q000502:physiology; D057566:Self Report; D019462:Syncope, Vasovagal / Q000503:physiopathology* / Q000523:psychology*; D014741:Video Recording; D055815:Young Adult
keywords: Blood fears; Disgust; Fainting history; Impedance cardiography; Vasovagal