Background and aim: Subjective symptoms of Internet addiction (IA), such as interpersonal and healthrelated problems (IH-RP), do not correlate with objective physiological parameters. This study aimed to investigate the cardiovascular reactivity after physical exercise in 15-16-year-old adolescents showing different severities of symptoms of health-related problems due to Internet overuse. Methods: This study included 20 healthy adolescents (boys, 15-16 years) with different risks of IA (by the Chen internet addiction scale [CIAS]). The physical exercise test was to perform a standing broad jump three times. The arterial blood pressures and heart rates were recorded before, immediately after, and at 4 minutes of rest after exercise. Results and discussion: The total sample of adolescents was divided into two groups, that is, those with IH-RP scores of 12 or less (Group I, n 5 12) and those scoring more than 12 points (Group II, n 5 8). The diastolic blood pressure significantly increased after exercise in group II, whereas it remained stable in group I. The heart rate in group I tended to increase, but the changes were not statistically significant. Group II adolescents showed significant increases in heart rate, and at rest, this parameter was significantly higher than the baseline value. Conclusions: Adolescents with a risk of IA and severe symptoms of interpersonal and health-related problems had increased sympathetic activity during and after speed-strength physical exercise compared to those without the aforementioned symptoms.  Kulcsszavak: nternet addiction, cardiovascular system, adolescents