PP.21.02] MENTAL STRESS, PH AND PCO2 AND SYSTOLIC HYPERTENSION

Abstract

Objective: Resilence is known to be a major risk factor for the development of primary hypertension. Persisting overcompensation during mental irritation increases pH values and oxygen binding in blood samples by respiratory overcompensation. Is this metabolic effect dependent on blood pressure values? Design and method: 23 healthy young officer trainees were tested for pCO2, O2 saturation, pH values (PhOX-M, TECOM, Austria) and blood pressure values (Beurer, Ulm, Germany) during the sympatho-adrenal anticipation phase before their first parachute jump. Both, the entire group as well as two subgroups, consisting of systolic blood pressure values above average and below average (normal values) have been investigated. Results: The relation pH/pCO2, indicative of breathing frequency and acid management shows a rather weak negative linear correlation in the entire group (r = 0.329). The normal systolic blood pressure group shows no correlation at all, the high systolic blood pressure group developed a highly significant negative correlation of pH/CO2 (r = 0.656, p < 0.001). At the same time, O2 saturation increases with increasingly alkaline blood and decreasing pCO2 (p < 0.05). Conclusions: Mental stimulation increases blood pH by respiratory overcompensation and thereby increases O2 binding. Consequently, less O2 reaches e.g. heart tissue at higher demand during a sympatho-adrenal anticipation phase, which is by no means uncommom during day-to-day exertions. This symptom is much less significant at normal blood pressure values, but highly significant at higher systolic blood pressure values. Therefore, increased systolic blood pressure values institute an integral part of significantly negative metabolic effects upon the heart during even commonplace mental stimulation or irritation.