P8 THE EFFECT OF CAFFEINE ON MENTAL STRESS RELATED CARDIOVASCULAR RESPONSE

Abstract

Background: Caffeine, the most widely used pharmacologically active substance causes mental stimulation and a slight raising of blood pressure. The aim of our work was to evaluate the effect of caffeine on the cardiovascular system during rest and during mental stress. Methods: RR interval duration, arterial blood pressure and Laser-Doppler (LD) flux were monitored in 40 healthy volunteers (aged 21.98 ± 0.9 years) before and after ingestion of 200 mg of caffeine. The measurements were performed during rest (360s), during mental stress (90s) and during relaxation after mental stress (510s). The measurements were performed twice: under the effect of caffeine and under the effect of placebo. The study was approved by the National Medical Ethics Committee; written informed consent was obtained from each subject. Results: During resting condition RR interval (ms) increased (910,49 ± 130,5 before and 958,96 ± 130,66 after) (p<0,05), systolic blood pressure (mm Hg) increased (119,35 ± 14,3 before and 127,54 ± 15,9 after) (p<0,05), diastolic blood pressure (mm Hg) increased (68,78 ± 11,2 and 76,20 ± 11,6) (p<0,05), LD flux decreased (150,05 ± 96,4 and 115,15 ± 86,7) (p<0,05) and temperature decreased (30,92 ± 3,5 and 29,71 ± 3,5) (p<0,05) after ingestion of caffeine. During mental stress systolic and diastolic blood pressure increased significantly less, RR interval was nearly the same and LD flux after mental stress increased more and earlier after ingestion of caffeine. Conclusion: Although caffeine raises blood pressure it has favourable effect on the cardiovascular system during and after mental stress.