Post-learning stress after a heartbeat perception training facilitates interoceptive accuracy in the heartbeat counting task, but not in the heartbeat discrimination task

Interoceptive accuracy (IAc), assessed using the heartbeat counting task (HCT), increased after heartbeat perception training (HBPT) and post-learning stressor (i.e., the socially evaluated cold pressor test; SECPT), suggesting facilitation of interoceptive perceptual learning after stress. Here we investigated whether this effect is due to undergoing HBPT or repeatedly performing the HCT, and if this effect is also observable in the heartbeat discrimination task (HDT). Healthy adults (N = 96, 80 women; 18 – 41 years; university students and staff, local community), were randomly assigned to one of four groups, two of which received HBPT, either followed by SECPT or a control condition (HBPT+stress / HBPT-stress, respectively). The other two groups completed an exteroceptive perceptual learning paradigm (visual perception task; VPT), followed by the SECPT or the control condition (VPT+stress / VPT-stress). We assessed IAc using the HCT and the HDT before (T1), 30 min (T2) and 24 h after the SECPT / control intervention (T3). The SECPT induced increases in systolic and diastolic blood pressure, heart rate, salivary cortisol, as well as of self-reported stress and pain. IAc in the HCT increased from T1 to T2 and to T3 in the HBPT+stress group only, whereas no effect was observed for IAc based on the HDT. Regression analyses indicated that lower cortisol responsiveness to the SECPT was associated with a larger increase in HCT based IAc over the 24 h interval (T2 to T3), suggesting that stronger cortisol responses inhibits overnight consolidation in interoceptive perceptual learning.