Interoceptive and psychosomatic medicine (2): Why is interoception important?

Interoception is the sense of the internal state of the body.
In contrast, “exteroception” captures information from the external environment, with sight and touch being its representatives.
Why is this interoception important for maintaining our health?

Adapting to Changes in Health

Our physical and mental states change daily.

Naturally, external circumstances change daily, and within them, internal states also change daily. For example, the menstrual cycle in women is an example of internal state changes. Not only the gynecological system but also other systems such as the gastrointestinal and circulatory systems are constantly changing. As a result, overall health also changes. It could be said that “living is changing.”

Whether we can adequately respond to such changes in internal states (simply put, health) is the key to maintaining health amid daily stress. For example, by acting according to daily changes in health such as “Today I’m feeling well, so let’s push through with work a bit” or “I’m not feeling well today, so let’s take it easy” or “Let’s rest early,” you can maintain your health.

So, what determines whether we can respond appropriately or not?

It’s easy to imagine that factors such as “resilience,” “adaptability,” “responsiveness,” “(flexibility in response to situations),” and “appropriate coping behaviors” are involved. However, before that, what’s important is to properly grasp (understand) the state. Only by properly grasping the state can we flexibly “adapt,” “respond,” “cope,” and as a result, “recover.” Of course, just grasping is not enough, but it’s the basic for appropriate response.

Interoception as the Foundation for Adaptation

Interoception is responsible for the “proper understanding of internal states.”

Interoception primarily includes muscle tension, body temperature, blood sugar levels, blood pressure, and heart rate (= lower-order interoception).
Comprehensive “feelings of physical well-being” or “feelings of physical discomfort” based on primary senses are also part of interoception (= higher-order interoception).
These senses are essential for us to recognize, understand, and maintain our own health.
Specifically…

Interoception allows adjustment of activities according to changes in one’s physical condition.
If one can appropriately recognize their own physical abnormalities or discomfort, it leads to early detection of health issues and early intervention.
By sensing changes due to lifestyle habits such as exercise and nutrition, appropriate adjustments to lifestyle habits lead to health maintenance.

These are some of the points.

Decision-Making and Intuition with Interoception

We make various choices and decisions in our daily lives.

Among these are major decisions such as “who to spend our life with,” “which company to work for,” “whether to undergo surgery,” as well as daily small choices like “what to eat today,” “what to do next,” “to continue or take a break,” etc., at various levels.

Major decisions that require thoughtful consideration, comprehensive judgment, etc., are made by referring to intuitive factors, judging the overall situation of people’s opinions and circumstances. This involves fairly high-level judgment and selection. On the other hand, small choices like whether to eat the food in front of you, what to do next, etc., are often made intuitively without much deep thought. It has become evident that information from the physical level significantly influences these intuitive choices and decisions.

Antonio Damasio’s “Somatic Marker Hypothesis” suggests that bodily reactions based on emotions and experiences (somatic markers) influence decision-making. “Somatic” refers to the body. The “somatic markers” referred to here are bodily sensations and reactions arising from past experiences, and interoception is significantly involved. Damasio argues that somatic markers play an important role in our decision-making by providing the necessary information for rational judgment.

Our choices and decisions not only affect health but also greatly influence life, making it clear how important interoception is.

Relationship with Stress-Related Disorders and Lifestyle Diseases

Furthermore, interoception has been found to be involved in the pathophysiology of various diseases such as stress-related disorders, mental disorders, and lifestyle diseases. In other words, if this interoception does not function properly, it can lead to the onset of these diseases, and the functioning of interoception is highly related to prognosis. For example, a dulled interoception is observed in depression and is thought to be related to various physical symptoms accompanying depression such as headaches, gastrointestinal discomfort, and dizziness. In psychosomatic disorders, it is related to cognitive biases of symptoms and is correlated with symptoms.

Also, in heart failure, which is one of lifestyle diseases, “home-based rehabilitation” focusing on appropriate exercise greatly affects its prognosis. It has been revealed by research that interoception significantly influences the effects of this rehabilitation. Not only in heart failure but also in various lifestyle diseases, self-management at home such as meals and exercise is the most important. For example, in diabetes, while medication and insulin are important, whether one can control their blood sugar by measuring it at home, controlling meal calories, and performing moderate exercise greatly affects its prognosis.

Interoception greatly influences such home-based rehabilitation and self-management.
Why? Because properly grasping one’s physical condition (interoception) forms the basis for self-management, such as exercising according to changes in physical condition or adjusting meals according to blood sugar control status.

Therefore, interoception is considered to play a significant role in controlling and treating these diseases, and the development of treatment methods to properly adjust interoception is expected and being studied.

Interoception serves as the foundation for maintaining our physical and mental health and is involved in choices and decision-making, making it a highly important function.

(Kanbara K. LABs Psychosomatic Medicine, https://psychosom.net/column/interoception2, Jun 2023)

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References

Kanbara, K., Fukunaga, M. Links among emotional awareness, somatic awareness and autonomic homeostatic processing. BioPsychoSocial Med 10, 16 (2016). https://doi.org/10.1186/s13030-016-0059-3

Miyazaki S. and others, Heartbeat tracking task performance, an indicator of interoceptive accuracy, is associated with improvement of exercise tolerance in patients undergoing home-based cardiac rehabilitation, European Heart Journal – Digital Health, Vol 3, 2, 2022, https://doi.org/10.1093/ehjdh/ztac008

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