Resting vagal control and resilience as predictors of cardiovascular allostasis in peacekeepers

Figures & data

Figure 1. Mean ± standard error of interbeat interval (a) and heart rate variability (b). Both measures were calculated for the first 2 min of the five conditions: basal, preparation, speech task, arithmetic task, and recovery (N = 50 participants). RMSSD: root mean square of successive differences between adjacent RR intervals in milliseconds. A one-way repeated-measured analysis of variance (RM-ANOVA) was conducted with conditions as within-subject factor, separately for interbeat interval and RMSSD, with Greenhouse–Geisser correction. *p < 0.05 for comparison with basal and with recovery conditions; #p < 0.05 for comparison with preparation condition; Tukey's HSD post hoc test.

Table 1. Trier Social Stress Test tasks: Spearman correlations between reactivity or recovery indexes (interbeat interval [ms] and heart rate variability [ms]) and individual predispositions (resting vagal control or trait resilience).

	Resting vagal control	Trait resilience (ER-89)
Interbeat (R–R) interval (ms)
Reactivity indexes
Basal – speech	ρ = 0.50; p = 0.0003	ρ = 0.29; p = 0.047
Basal – arithmetic	ρ = 0.54; p = 0.0001	ρ = 0.38; p = 0.007
Recovery indexes
Recovery – speech	ρ = 0.45; p = 0.001	ρ = 0.22; p = 0.13
Recovery – arithmetic	ρ = 0.53; p = 0.0001	ρ = 0.29; p = 0.004
Heart rate variability (ms)
Reactivity indexes
Basal – speech	ρ = 0.76; p = 0.0001	ρ = 0.32; p = 0.003
Basal – arithmetic	ρ = 0.72; p = 0.0001	ρ = 0.14; p = 0.32
Recovery indexes
Recovery – speech	ρ = 0.60; p = 0.0001	ρ = 0.32; p = 0.03
Recovery – arithmetic	ρ = 0.53; p = 0.0001	ρ = 0.21; p = 0.14

Heart rate variability was calculated as the root mean square of successive differences between adjacent RR intervals in ms: RMSSD_2min, resting vagal control was measured by the root mean square of successive differences between adjacent RR intervals (RMSSD_5min) during the whole 5-min basal condition. Trait resilience was measured by the Ego-Resiliency Scale (ER-89). Sample size = 50 participants.