Specific Features of Regional Blood Flow During Local Exposure to Cold in Foreign Students

Abstract

Physiological adaptation to the distinctly continental climate of the Volgograd Region underlies successful sociocultural adaptation of foreign students. The first to be activated in an adaptative response is the circulatory system, determining thermoregulation and homeostasis. The purpose of this research was to study the parameters of regional blood flow in the forearm–hand segment in foreign students in response to local cold stress using rheovasography of the upper limbs. Materials and methods. The study involved 36 Indian students of Volgograd State Medical University aged 19–21 years (mean age 20.1 ± 1.3 years). Rheograms of the upper limbs were recorded at rest, during local cold exposure of the left hand, and during the recovery period (1st, 3rd and 5th minutes) using Reo-Spektr 2 complex (Neurosoft, Ivanovo, Russia). Results. The identified blood flow asymmetry is characterized by a decreased tone of large arteries on the right and a predominant influence of the vascular component on the compensatory increase in the venous tone. Vascular reactivity at local cold exposure can vary due to the imperfection of protective and compensatory reactions. Cold-induced vasoconstriction was mostly realized through the activation of cardiac activity by the central circuit (vasoconstrictor response in the forearm segment), while vasodilation in the hand segment was achieved through an adaptive reaction of the vascular smooth muscle component. In the hand segment, a short-term decrease in the tone of the vascular wall of the precapillaries during local exposure to cold was followed by adaptive reactions of the blood flow in the 1st minute of recovery, indicating a possible flow of blood from the arteries into the veins through arteriovenous anastomoses, bypassing the capillary network. Improved venous outflow from the region by the 5th minute of recovery was recorded only on the right, while no significant vascular dilatation was detected on the left. The authors proposed a vascular reactivity index and determined rheovasography parameters that can be used as informative criteria for individual typological differences in the body’s adaptive response to cold exposure in foreign students.