title: Playing a violent television game affects heart rate variability.
abstract: OBJECTIVE
  To investigate how playing a violent/nonviolent television game during the evening affects sympathetic and parasympathetic reactions during and after playing as well as sleep quality during the night after playing.
  
  
  METHODS
  In total, 19 boys, 12-15 years of age, played television games on two occasions in their homes and participated once without gaming. Heart rate, heart rate variability (HRV) and physical activity were measured during gaming/participating and the night to follow using a portable combined heart rate and movement sensor. A sleep diary and questionnaires about gaming experiences and session-specific experiences were filled in. Criteria for Selection of Games: Violent game involves/rewards direct physical violence (no handguns) against another person, and nonviolent game involves/rewards no violence; same game design ('third-person game'); conducted in the same manner; no differences concerning motor activity; similar sound and light effects; no sexual content, violence against women or racial overtones.
  
  
  RESULTS
  During violent (vs. nonviolent) gaming, there was significantly higher activity of the very low frequency component of the HRV and total power. During the night after playing, very low frequency, low frequency and high frequency components were significantly higher during the violent (vs. nonviolent) condition, just as total power. There were no significant differences between the three conditions (violent/nonviolent/no gaming) with respect to an index reflecting subjectively perceived sleep difficulties. Nor was there any difference between violent and nonviolent condition for any single sleep item.
  
  
  CONCLUSIONS
  Violent gaming induces different autonomic responses in boys compared to nonviolent gaming--during playing and during the following night--suggesting different emotional responses. Subjectively perceived sleep quality is not influenced after a single gaming experience. Future studies should address the development of the autonomic balance after gaming over longer time than a night, physiological adaptation to frequent gaming and potential gender differences.
authors.affiliation: Stress Research Institute, Stockholm University, Stockholm, Sweden. malena.ivarsson@stressforskning.su.se
authors.forename: Malena
authors.initials: M
authors.lastname: Ivarsson
authors.forename: Martin
authors.initials: M
authors.lastname: Anderson
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Akerstedt
authors.forename: Frank
authors.initials: F
authors.lastname: Lindblad
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002648:Child; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009043:Motor Activity; D012890:Sleep; D012893:Sleep Wake Disorders / Q000503:physiopathology; D011795:Surveys and Questionnaires; D013690:Television; D018910:Video Games / Q000009:adverse effects*; D014754:Violence