Body-sensitive people are tuned into their heart and their stomach

We know from past research that some people are better than others at being able to detect their own heartbeat. There's lots of research on that topic, partly because it's so easy to compare people's estimates of their heartbeats against the true reading. But is this a characteristic that generalises? Are people who are accurate at detecting their cardiac activity also in-tune with their other internal bodily functions?

Before now, just one study from the early 80s had looked for and found an association between cardiac awareness and gastric awareness. But that study relied on an uncomfortable sounding procedure in which participants had to swallow a balloon. That necessarily ruled out a lot of potential participants who wouldn't have wanted to do such a thing, and the internal gastric sensations that the remaining participants detected were artificially induced.

Now Beate Herbert and her colleagues have used a more natural test of gastric awareness. Forty-nine healthy women fasted for four hours before arriving at the lab where they were instructed to drink water until they felt full. The container they drank from was opaque and re-filled after each swig, so that there was no way for the women to judge visually how much they'd drunk. The participants also completed a test of their heartbeat awareness. For both tasks, medical equipment in the form of electrocardiogram (ECG) and electrogastrogram (EGG) provided objective measures of heart and stomach activity.

The key finding is that women who were more accurate in detecting their own heartbeats also tended to stop drinking earlier, as if they were more sensitive to internal feelings of fullness. The EGG provided objective confirmation that they experienced less gastric activity than the other participants before stopping drinking, so it wasn't the case that their stomachs were actually more full or issuing more powerful signals. Rather the heartbeat-sensitive women seemed to be particularly sensitive to signals arising from their stomachs. There were no links between either cardio or gastric awareness and anxiety.

Herbert and her team concluded: "'Interoceptive awareness' as assessed by heartbeat perception seems to represent a better ability to focus, to perceive and to process internal bodily information across visceral modalities, such as gastric signals, with cardiac and gastric signals both representing bodily cues that show perceivable activity changes during situations of everyday life."

Further reading

Herbert, B., Muth, E., Pollatos, O., and Herbert, C. (2012). Interoception across Modalities: On the Relationship between Cardiac Awareness and the Sensitivity for Gastric Functions. PLoS ONE, 7 (5) DOI: 10.1371/journal.pone.0036646