[Stress, blood pressure reactivity and arterial hypertension: not an unambiguous relation]

In order to determine the different ways the hypertensives' blood pressure would react during mental stress, 49 patients, 27 women and 22 men, were submitted at the Stroop Word Colour Conflict Test. Their haemodynamic parameters were recorded by finger photoplethysmography (Finapres device), with equidistant sampling (2 Hz). Temporal and spectral analysis showed evidence of: a quick and short elevation of BP and HR and a greater variability of SBP, as shown by the increase of the MF (66-128 mHZ) module. Patients can be divided into 3 clusters according to the reactivity of SBP. Group I (N, mean +/- sigma) 13, + 32.7 +/- 8 mmHg; group II 24, + 10.3 +/- 6; group III 12, -10.2 +/- 7. They were comparable on anxiety level and on any demographic and clinical feature. In group III, the higher NA at rest, the bigger the fall of SBP when stressed. The cognitive efficiency of these patients is increased by stress. Spectral analysis: Mid frequency (66-128 mHz) components are markedly higher in group III, before, during and after SWCCT showing a higher sympathetic tonus.

The reactivity of BP is not homogeneous. One fourth of our patients showed a decrease of SBP during the cognitive treatment stage of the test without showing a decrease of sympathetic tone. Anxiety level is not predictive of BP's response.