Effect of one‐time successive immersion of the right hand into ice‐cold and warm water on blood pressure in prehypertensives
Authors: Shekh Vira (Vera) Evgenievna 
Published: June 2021

An early diagnostic and awareness of hypertension are crucial for controlling and prevention from further its development. The dysfunction of the autonomic nervous system (ANS) is a cornerstone of hypertension pathophysiology which underlies the initiation and development of hypertension. The HRV is commonly used for the evaluation of ANS activity. Though physiological/therapeutic effects of hydrotherapy for maintaining health, preventing, and treating the diseases, were well documented, the scientific base of these effects till now remains unclear.The 79 normotensive and 76 prehypertensive men, 102 normotensive and 50 prehypertensive women (117.4±0.6 mm Hg and 135.0±1.0 mm Hg, 111.1±0.6 mm Hg and 126.3±0.8 mm Hg for SBP, respectively) were enrolled from V.N. Karazin Kharkiv National University student population. All of them gave written informed consents.The ECG was continually recorded during the 5‐minutes resting stage and cold‐warm test (CWT): 5‐minutes immersion of the right hand into warm water (37°C) following by 1‐minute immersion of the hand into the ice‐cold water. HR, LnLF and HF HRV power were obtained by digital 2‐channel ECG amplifier (CardioLab 2010, Ukraine). HRV was assessed in the frequency‐domain analysis during the resting and warm‐water stages. SBP and DBP were recorded at the end of the resting and warm‐water stages by means the automatic digital sphygmomanometer (Nissei WS‐1011, Ltd, Japan) and MBP was calculated. Three‐way repeated measure MANOVA was used to compare HR, MBP, LnLF, LnHF HRV power by sex, the presence of prehypertension, and CWT. Two‐way MANOVA was used to analyze the possible effect of sex and prehypertension on cardiovascular and HRV responses to cold‐warm test. Statistical analysis was performed with the SPSS statistical program, version 22.During CWT the HR decreased significantly compared with the resting stage in normotensive and prehypertensive groups (P<0.001 for both), MBP increased in normotensive subjects (P=0.032) while decreased in the prehypertensive group (P<0.001). The LnHF power widely used as an index of cardiovagal activity tended to be increased in normotensive subjects (P=0.054) while the LnLF power indicating, according to our hypothesis, an index of sympathoinhibition, increased only in the normotensive group at high significant level (P=0.003).Sex differences were found between normotensive subjects in ΔHR, ΔLnLF, and ΔLnHF HRV power, such that LnLF and LnHF increased more and HR decreased more in normotensive women than in men (P=0.034, P=0.010, and P=0.015, respectively) indicating that reduction of HR due to activation of cardiovagal activity and sympathoinhibition was higher in normotensive women.So, during CWT the increase in parasympathetic activity and sympathoinhibition led to the reduction of HR in normotensive subjects, while prehypertensive subjects demonstrated the decrease of both HR and MBP without change of HRV indices possibly due to the reduction of tonic activity of the sympathetic nervous system. This cold‐warm test may be used for early diagnostic of hypertension since the MBP in normotensives significantly increased and in prehypertensives decreased at high significant level.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.