Comparing Habituation of Cardiovascular Reactivity to Acute Mental Stress and the Cold Pressor Test

Abstract

Exaggerated cardiovascular reactivity (CVR) to acute laboratory stress has been linked to the development of cardiovascular disease. However, recent evidence within the field of psychophysiology reveals that exaggerated CVR may actually be adaptive for long-term health if the response is relatively brief and decreases across subsequent stress exposures (i.e., habituation). Extensive research has validated the occurrence of CVR habituation, specifically to repeated mental stress. However, to our knowledge, no research to date has attempted to directly compare CVR habituation to mental stress with other types of stress tasks (i.e., the cold pressor test; CPT) within the same individuals. The present study aimed to compare CVR habituation to mental stress and CPT across repeated exposures. Based upon prior CVR profiles for repeated mental stress and CPT, we hypothesized that CVR habituation would be observable in response to repeated mental stress, but not repeated CPT. Sixteen healthy young adults (9M/7F, 21±1 yrs, 23±1kg/m2) participated in three experimental sessions. The initial two sessions were administered during a single laboratory visit and separated by a 45 min rest period. The third session occurred one month later at a follow-up visit. Each session included a mental stress trial (5 min baseline, 5 min mental arithmetic task) and a CPT trial (3 min baseline, 2 min CPT), with continuous recordings of heart rate (HR; electrocardiogram) and beat-by-beat arterial blood pressure (finger plethysmography). Reactivity (i.e., stress — baseline) was calculated separately for HR and mean arterial pressure (MAP). Repeated measures ANOVAs revealed a significant main effect of time for HR, F(2, 30) = 6.57, p = 0.004, η2 = 0.30, and MAP, F(2, 30) = 4.37, p = 0.02, η2 = 0.23 in response to the repeated mental stress, but not in response to the repeated CPT (all p-values ≥ 0.05). Post hoc analyses demonstrated HR reactivity to be significantly lower during session 3 of the mental stress (Δ20±9 beats/min, ps ≤ 0.015) compared to session 1 (Δ25±10 beats/min) and session 2 (Δ23±10 beats/min). No significant differences were observed between HR reactivity at sessions 1 and 2 of mental stress ( p = 0.151). MAP reactivity was significantly lower during session 2 (Δ13±5 mmHg) and session 3 (Δ12±6 mmHg) of the mental stress compared to session 1 (Δ15±5 mmHg, ps ≤ 0.030). No significant differences were observed between MAP reactivity at sessions 2 and 3 of mental stress ( p = 0.374). In summary, HR and MAP reactivity significantly habituated in response to repeated mental stress, but not in response to the repeated CPT. Findings suggest that the cardiovascular system adapts to repeated laboratory mental stress, but remains consistently engaged during repeated exposures to the CPT. National Heart, Lung, and Blood Institute (HL-122919). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.