Adaptation reactions of hemodynamic systems on artificially modulated stress in healthy individuals

Aim. To study the influence of artificially created stress on hemodynamic parameters  of peripheral microcirculation and variability of the heart rhythm in somatically healthy young individuals.

Materials and Methods. In the study 30 individuals were involved (of them 16 men)  with the mean age 18.2±1.1 years. An artificial stress was created using Stroop method. Assessment of characteristics of hemodynamics of microcirculation (HM) was performed by the method of dynamic scattering of light from erythrocytes. The signal was integrated in the form of three hemodynamic indexes: HI (Hemodynamic Indexes). Low frequency index (HI1) was determined by a slow interlayer interaction, high frequency area (HI3) characterized fast shearing of layers. HI2 took intermediate position (precapillary and capillary blood flow). Variability of cardiointervals isolated from pulse component, was assessed by method of variation pulsometry (Heart Rate Variability, HRV).

Results. In the course of study, increase in the heart rate (HR) in the stage of testing was  observed that confirms a high extent of stress load. In hemodynamics, redistribution of blood  flow was noted toward slow shear velocities (near-wall blood flow). After cessation of stress load,  hemodynamic parameters declined and returned to previous values. Parameters characterizing variability of rhythm – LF (sympathetic component), HF (vagal activity), CVI (non-linear  parasympathetic index) showed a tendency to growth; here, LF/HF ratio did not change.

Conclusion. In result of the carried out study it was possible to formulate a multifactor  picture of variation of parameters of microcirculation and of autonomic regulation of cardiac rhythm specific of reactions of adaptation to induced stress. The quantitative criteria of the  obtained shears may be integrated into stress indexes to be used in clinical practice. A portable mDLS sensor may be supplemented with specific assessment criteria and used for monitoring  of adaptive reactions induced by stressful situations, and for taking early diagnostic and prognostic decisions in the clinical practice, and for self-control of a patient.