title: The effect of violent and nonviolent video games on heart rate variability, sleep, and emotions in adolescents with different violent gaming habits.
abstract: OBJECTIVE
  To study cardiac, sleep-related, and emotional reactions to playing violent (VG) versus nonviolent video games (NVG) in adolescents with different gaming habits.
  
  
  METHODS
  Thirty boys (aged 13-16 years, standard deviation = 0.9), half of them low-exposed (≤1 h/d) and half high-exposed (≥3 h/d) to violent games, played a VG/NVG for 2 hours during two different evenings in their homes. Heart rate (HR) and HR variability were registered from before start until next morning. A questionnaire about emotional reactions was administered after gaming sessions and a sleep diary on the following mornings.
  
  
  RESULTS
  During sleep, there were significant interaction effects between group and gaming condition for HR (means [standard errors] for low-exposed: NVG 63.8 [2.2] and VG 67.7 [2.4]; for high-exposed: NVG 65.5 [1.9] and VG 62.7 [1.9]; F(1,28) = 9.22, p = .005). There was also a significant interaction for sleep quality (low-exposed: NVG 4.3 [0.2] and VG 3.7 [0.3]); high-exposed: NVG 4.4 [0.2] and VG 4.4 [0.2]; F(1,28) = 3.51, p = .036, one sided), and sadness after playing (low-exposed: NVG 1.0 [0.0] and VG 1.4 [0.2]; high-exposed: NVG 1.2 [0.1] and VG 1.1 [0.1]; (F(1,27) = 6.29, p = .009, one sided).
  
  
  CONCLUSIONS
  Different combinations of the extent of (low versus high) previous VG and experimental exposure to a VG or an NVG are associated with different reaction patterns-physiologically, emotionally, and sleep related. Desensitizing effects or selection bias stand out as possible explanations.
authors: Stress Research Institute, Stockholm University, SE-106 91 Stockholm, Sweden. malena.ivarsson@stressforskning.su.se
authors: Malena
authors: M
authors: Ivarsson
authors: Martin
authors: M
authors: Anderson
authors: Torbjörn
authors: T
authors: Åkerstedt
authors: Frank
authors: F
authors: Lindblad
mesh_terms: D000223:Adaptation, Psychological; D000293:Adolescent; D000294:Adolescent Behavior; D004644:Emotions / Q000502:physiology*; D006184:Habits; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008499:Medical Records; D008960:Models, Psychological; D000297:Psychology, Adolescent; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000209:etiology; D011795:Surveys and Questionnaires; D018910:Video Games / Q000009:adverse effects; D014754:Violence / Q000523:psychology
keywords: children; desensitization; emotion; heart rate variability; sleep quality; violent video game