Vagally mediated HRV predicting ESST performance (post stimulation)
The linear regression revealed a significant effect of vmHRV reactivity on SSRT with phasic increases in vmHRV during the ESST predicting faster SSRTs and vice versa, β = -4.09, SE = 1.93, t (51) = 2.12, p < .05. We further found the interaction between tonic and phasic CVA to exert a significant effect on SSRTs, β = 0.05, SE = 0.03, t (51) = 2.20, p < .05 (see Table 3). A post-hoc simple slope analysis revealed that the effect of vmHRV reactivity on ESST performance differed significantly between participants with high and low resting vmHRV (see Table 4). Compared to participants with high resting vmHRV, an increase/decrease of vmHRV during the ESST predicted faster/slower SSRTs in participants with low resting vmHRV (see Figure 2). Additionally, the results of the linear regression show a significant effect of age on ESST performance, in that higher age predicted slower SSRTs, β = 4.49, SE = 1.69,t (51) = 2.65, p < .05. No further significant associations were found (see Table 3).