The Art and Science of Interoception

the idea that we humans have five senses — sight, sound, smell, touch, and taste—is a belief that dates back 2,000 years to Aristotle.1

Back then, it was a decent guess, but neuroscience has advanced significantly since the days of ancient Greece. It turns out that we have at least four additional senses—and the most underrated and practical of them is known as interoception.

The word has two parts: “intero–” refers to “internal” and “–ception” to “awareness.” In essence, it means awareness of our internal state, which includes learned associations, memories, emotions, and all the data running through the interconnected pipelines of the 100 billion neurons in your body.2

Intero-ception can be contrasted with “extero-ception,” which involves receiving data through the external senses. Most of us tend to prioritize external sense data—like endlessly refreshing a newsfeed after dinner when internally, our body is sending signals to recover and begin winding down.

By learning to cultivate internal receptivity, we can listen to the treasure trove of data coming from the activation shifts of neurotransmitters—like adenosine cueing a need for sleep, a change in our breathing mechanics signaling a shift in our arousal response, or just being aware of how rested we feel upon waking and making choices about our day accordingly.

NSDR has also been shown to flush cortisol and norepinephrine—aka adrenaline—from the system so that your body is naturally primed to be more receptive to the training