Assessment of Autonomic and Cardiovascular Reactivity in Response to Cold Pressor in Prehypertensive Individuals

Abstract

Modulation of the autonomic nervous system (ANS) activity allows human organism to effectively respond to challenges in the environment via changes in, for example, heart rate (HR) and blood pressure (BP). Various factors, like cold pressor test (CPT) can impact ANS activity and may be used for the assessment of ANS and cardiovascular reactivity, i.e. physiological systems response to challenges in the environment. The commonly used method to evaluate the ANS modulation is HRV (heart rate variability). The objective of the study was to compare the autonomic and cardiovascular reactivities in response to cold pressor test between prehypertensive and normotensive individuals of both genders. Baseline HR, SBP (systolic blood pressure), DBP (diastolic blood pressure), LF (low frequency) and HF (high frequency) HRV power were recorded in 307 normotensive and prehypertensive young men and women. Immersion of the right hand into ice cold water for one minute was performed to compare cardiovascular reactivity to CPT between these groups. General linear model was used to test for effect of gender and prehypertension on baseline cardiovascular and HRV variables and to compare ANS and cardiovascular reactivities. Stepwise multiple linear regression analysis was used to reveal predictors of ΔSBP and ΔDBP. Blood pressure response to CPT, negatively associated with resting blood pressure and positively associated with BMI (body mass index), was less in prehypertensive men compared with normotensive men and prehypertensive women. Gender-based differences of ∆SBP and ∆DBP may be explained by differences in blood pressure and height and by negative association between ∆SBP and resting LnLF which was less in women. In conclusion, ANS and cardiovascular reactivities to cold press were less in prehypertensive men compared with normotensive men and prehypertensive women indicating a decrease in the ability of prehypertensive men effectively respond to challenges in the environment via changes in ANS and cardiovascular function.