Interoception: the ‘hidden’ sense

What is it? 

We all know the five basic senses: touch, taste, smell, sight, and hearing. But there’s actually another lesser-known sense, interoception. Interoception is our ability to notice our internal body signals, like tense muscles, a racing heart, hunger or fullness. We have receptors inside our organs that send signals to the brain with information about what is going on inside our body. This process is very important for maintaining homeostasis (a stable and constant internal environment) and is critical to survival.  

Why is it important? 

Imagine what would happen if we were not able to sense hunger cues like low blood sugar or a pulling sensation in our stomach? What if we were not able to tell that we are thirsty? People with sensory processing difficulties may have trouble making sense of information like this, which can make self-regulation a challenge. Self-regulation means acknowledging the changes in body experiences and taking corrective actions to regain homeostasis. For example, we know to take a drink when our throat feels dry, or to take a few deep breaths when we feel agitated. If we are not clearly aware how our body is feeling, it will be very difficult for us to respond to these body experiences accordingly. 

People can be hyper-responsive or hypo-responsive to interoception sensory input. For those who are hyper-responsive (or hypersensitive), even the slightest change like feeling of hunger can cause them to feel extremely anxious. A room that is a little too warm can be exceedingly distracting. Being alone in a room so quiet that one can hear their own heartbeat can be a nerve wrecking experience. For those who are hypo-responsive (or hyposensitive), the sensations might be too small or unreliable, and they might feel nothing and miss out on important clues. They may not realise they are hungry until they are completely starving.  

Individuals with anorexia nervosa (AN) may have disrupted internal body sensations in food-related settings. Patients with AN often ignore hunger cues in periods of self-starvation, despite clamorous signaling from hormones such as ghrelin (a hormone that sends a signal to your brain to feel hungry) (Culbert et al. 2016). Processing of interoceptive signals is also altered during meal anticipation, contributing to high anxiety and shortness of breath during mealtimes (Khalsa et al. 2015). Overall, dysfunctional interoceptive awareness may be one of the key drivers behind anxiety in anorexia nervosa. 

Altered interoception may also affect those with autism (DuBois et al. 2016). Autistic people may have inaccurate perception of fatigue or pain. They might also have trouble equating a racing heart and shallow breaths with fear. Failing to act on clues like this in a timely fashion leads to anxiety building up until it is skyrocketing. This lack of interoceptive awareness could contribute to explosive behaviours, because it’s not until the emotions are so big that an eruption occurs.  

Interoception and emotion regulation 

Interoception can also be tied to our mood. We all have very unique inner experiences when it comes to feeling emotions. What does your body feel like when you are anxious? For some, this can be ‘a frightened feeling like butterflies in the stomach’. There are also people who describe anxiety as a tight chest pain. Everyone is different, and understanding what is our unique way of feeling emotions is key for emotion regulation. Those who struggle with interoceptive input and are not as tuned in to body signals can have difficulties interpreting and identifying emotions. Confusion about the emotion being felt is called alexithymia and is commonly seen in people with anorexia nervosa and/or autism (Westwood et al. 2017). Not being able to identify and deal with the emotion being felt can be a very overwhelming and exhausting experience, often leading to meltdowns. This dysregulation of interoceptive signals sometimes is wrongly perceived as a lack of emotional maturity, which adds even more stress to the person experiencing it. 

How to improve our interoceptive awareness? 
There is a variety of strategies we can use to develop interoceptive awareness. These activities don’t take long and can be usefully incorporated into a daily routine, such as first thing in the morning or just before going to bed. Examples of these activities might include: 

• Yoga 
 

• Meditation 
 

• Breathing exercise (a variation, 4-7-8 breathing, is available, where you inhale for a count of four, hold it there and count to seven, and exhale for a count of eight. This allows you to pause between each breath.) 
 

• Mental body scan: slowly bring your attention down to your feet first, observe the sensations and continue with each area of your body. 
 

• Counting heartbeat: try to do this when you are alone and when it’s quiet, close your eyes, and feel your heartbeat without touching your chest or checking your pulse. You may find it hard to detect anything at first, but it will get better with practice! 


More resources can be found at: 
https://www.autism.org.uk/advice-and-guidance/professional-practice/interoception-wellbeing 
https://www.youtube.com/channel/UCyIovxevV3W2l2WXHDBkKxA 


References: 

1. Culbert, K. M., Racine, S. E., & Klump, K. L. (2016). Hormonal Factors and Disturbances in Eating Disorders. Current psychiatry reports, 18(7), 65. https://doi.org/10.1007/s11920-016-0701-6  
2. Khalsa, S. S., Craske, M. G., Li, W., Vangala, S., Strober, M., & Feusner, J. D. (2015). Altered interoceptive awareness in anorexia nervosa: Effects of meal anticipation, consumption and bodily arousal. The International journal of eating disorders, 48(7), 889–897. https://doi.org/10.1002/eat.22387  
3. DuBois, D., Ameis, S. H., Lai, M. C., Casanova, M. F., & Desarkar, P. (2016). Interoception in Autism Spectrum Disorder: A review. International journal of developmental neuroscience : the official journal of the International Society for Developmental Neuroscience, 52, 104–111. https://doi.org/10.1016/j.ijdevneu.2016.05.001 
4. Westwood, H., Kerr-Gaffney, J., Stahl, D., & Tchanturia, K. (2017). Alexithymia in eating disorders: Systematic review and meta-analyses of studies using the Toronto Alexithymia Scale. Journal of psychosomatic research, 99, 66-81