Vascular stress response in healthy children and adolescents

  • Dr Yun Chen, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg, Sweden
  • Ms Alexandra Brinkåker, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg,, Sweden
  • Dr Walter Osika, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg,, Sweden
  • Dr Frida Dangardt, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg,, Sweden
  • Mr Krister Berggren, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg,, Sweden
  • Dr Eva Gronowitz, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg,, Sweden
  • Prof Peter Friberg, Department of Molecular and Clinical Medicine, Sahlgrenska Academy/hospital at the University of Gothenburg,, Sweden

Objectives: It is common that school-children present with stress and psychosomatic symptoms. Stress elicits changes in sympathetic-parasympathetic balance, which might negatively affect the cardiovascular system. We know very little about the vascular stress response in school-children regarding age-related and sex-related differences. To investigate these, we measured noninvasively vascular response to mental arithmetic in cohorts of healthy children and adolescents.

Methods: Vascular function at the finger vascular bed was assessed using a novel peripheral arterial tonometric (PAT) technique with Endo-PAT® device in cohorts of children (7-12 years old, 116 girls and 127 boys) and adolescents (16-20 years old, 97 girls and 69 boys) from different schools in Gothenburg. Subjects were resting in a supine position and baseline pulse wave amplitude was recorded for 5 minutes, followed by 1-minute mental arithmetic. Pulse wave amplitude was recorded during this stress period and 1 minute after the stress test. PAT value was calculated as a ratio of pulse wave amplitude during and after stress to pulse wave amplitude at rest. Age and sex differences were tested by ANOVA (SPSS15.0).

Results: Both children and adolescents developed a vasoconstrictive PAT response, i.e. decrease in pulse wave amplitude during the first 30 seconds of mental arithmetic. This was followed by a vasodilatory PAT response, i.e. increase in pulse wave amplitude during the second 30-second period of mental arithmetic. The PAT value continued to increase during 1 minute after the stress test. In younger children, the vasoconstriction was 14.5% in girls and 19.1% in boys, and the vasodilatory response was 7.1% in girls and 4.8% in boys. There was no significant sex difference in this age group. In adolescents, the vasoconstriction was more pronounced in males than in females (37.8% vs 20.7%, p<0.0001). On the other hand, the vasodilatory response was more pronounced in females than in males (17.5% vs 3.1%, p=0.001). Moreover the adolescents had more pronounced vasoconstrictive response to mental stress than younger children.

Conclusion: In healthy school children and adolescents, the vascular stress response increases with age. The gender difference in vascular stress response is only apparent in late teenage. Thus, male adolescents have a more vasoconstrictive response, followed by a less vasodilatory response, to mental stress than the females. Given that laboratory-induced mental stress is a simulation of daily life stress, it is possible that the vascular stress responses we observed in school children and adolescents represent frequent daily life occurrences. It is possible that male adolescents have higher susceptibility to mental stress-related adverse events. Whether this could be a mechanism underlying the fact that men develop cardiovascular diseases earlier than age-matched women needs to be further investigated.