Acute stress after heartbeat perception training increases interoceptive accuracy in the heartbeat counting task, but not in the heartbeat discrimination task

Acute stress during the consolidation phase can improve
declarative memory. It is so far unknown whether perceptual
learning is also influenced by stress. This question is
relevant as perceptual learning plays a role in interoception,
while altered interoception might be an important
mechanism for symptom generation in stress-related disorders. Therefore, the aim of this study was to investigate
whether heartbeat perception training (HBPT)
can increase interoceptive accuracy (IAc), and whether
acute stress during the consolidation phase enhances this
learning effect. 99 healthy participants completed either
a HBPT or a visual perceptual task (VPT) and then underwent
either socially evaluated cold pressor test (SECPT)
or a control task (=4 groups). IAc was measured at three
occasions using a heartbeat counting task (HCT) and a
heartbeat discrimination task (HDT), i.e. (1) before training,
(2) 30 minutes after SECPT/control task and (3)
one day later. The SECPT induced a significant increase
in heart rate and blood pressure. The group that underwent
the HBPT and the SECPT also showed a significant
increase in IAc in the HCT from occasion (2) to (3). IAc
in the HCT, but not in the HDT, increased over measurement
occasions (1-3).
The results imply that the HBPT can
increase IAc in the HCT if acute stress is experienced in
the consolidation phase. This effect could play a role in
symptoms generation in stress-related
disorders. As the
HDT is typically described as more difficult than the HCT,
these enhancing effects may be limited to interoceptive
tasks of moderate difficulty.