Interoception and Physical Intelligence – Control Your Physiology

By on November 30, 2020

Physical intelligence, as described by authors Clare Dale and Patricia Peyton, is a measure of a person’s self-awareness and self-mastery. This is almost synonymous with the related term “interoception.” Interoception being the capacity to monitor – and thus influence – your own physiological state. This may in turn impact on mood and performance.

Interoception [is] the capacity to monitor – and thus influence – your own physiological state.

It’s a really interesting concept and the cool part is that it can be trained and improved. Doing so may have a direct effect on your health, cognitive performance, relationships, athleticism, and more.

What is Interoception?

Physical Intelligence Interoception

Recently, more and more people have been championing the importance of “EQ.” EQ is your “emotional quotient,” or your “emotional intelligence.” This is a measure measure of your capacity to understand and work with the emotions of others. This has further been extended to include knowledge and control of one’s own emotions.

See also: What is Emotional Intelligence? And How to Develop It

But while EQ is certainly important, it can actually be considered a mere facet of something even more important: physical intelligence.

Another way to think about this understanding how to interpret signals from and to use your own body.

Brain vs Body

If this sounds like something you should already know how to do, then… well yeah!

But, nevertheless, it’s also something a lot of us struggle with. It’s something we rarely think about. And it certainly doesn’t get taught in schools.

An Example of Interoception at Work

An example that I like to give is getting “hangry.”

Many of us become irritable when we’re hungry. But being physically intelligent would mean:

  • Recognizing when this has happened
  • Understanding why it has happened
  • Knowing how to deal with it to avoid an argument

So, why do we get hangry?

The answer has to do with the relationships between glucose, tryptophan, cortisol, and serotonin. See, when you’ve just eaten a big carb-packed meal, you also increase levels of tryptophan. This is an essential amino acid that is also a precursor to serotonin. That means that the brain can use it to synthesize serotonin. Tryptophan also has the ability to cross the blood-brain barrier via a carrier protein.

Interoception and hunger

What this means, is that after a big meal, the brain is high in serotonin (reference). You’ve probably heard serotonin referred to as the “happiness hormone.” Indeed, serotonin is both a hormone and neurotransmitter that encourages “feel good” emotions and helps us to relax. Over time, serotonin is broken down to create melatonin – the sleep hormone – which is why we feel content and drowsy after a big meal.

Enter: Hanger

But as you start to use up the available energy and glucose drops, so too do your serotonin levels deplete. Moreover, the body begins to release epinephrine (adrenaline), glucagon, growth hormone, and cortisol (reference). This makes sense: the body needs glucose as its primary energy source.

Physical Intelligence

These chemicals help to modulate the body’s response to low blood sugar (glucagon dissipates insulin for example but also helps to raise plasma glucose concentration via stimulating liver glucose production), while simultaneously making the individual more driven and focused. In other words, if you feel a bit stressed, you are more likely to go out and try to find food!

Before you know it, you’re bringing up personal insults and things that happened years ago.

But most people reading this have constant access to food and don’t need to go into fight-or-flight mode to start hunting and gathering. So instead, we simply become moody. That’s when our partner – who is also hangry – shouts at us for leaving the washing up and we bark back with a disproportionate response. Before you know it, you’re bringing up personal insults and things that happened years ago.

And then you both feel awful.

Physical Intelligence Applied

This is where physical intelligence comes in. The physically intelligent individual would understand that their thoughts might be a little extra negative owing to their hunger, and might therefore decide to postpone their heated response. They might understand how to restore calm balance to their autonomic nervous system in the short-term using breathing techniques, or they might use cognitive behavioral therapy to calm their racing thoughts. They might even galvanize that nervous energy and put it to good use by tidying the house while their food cooks.

Hanger interoception
You won’t like me when I’m hangry…

Thus, a little more physical intelligence in this one regard can potentially help a person to avoid arguments, improve their relationships, and even improve their performance.

Emotional Intelligence vs Physical Intelligence

The emotional intelligence meanwhile, comes from understanding that your other half might also be hungry. Or tired. Or anxious. EQ means recognizing this and therefore giving them the benefit of the doubt.

It also means using breathing techniques, or anger management techniques to avoid barking back and escalating an argument about bread or some other extremely-unimportant thing.

Emotional Intelligence

In the workplace, this kind of emotional intelligence and self-management is critical: from delivering the best speech by understanding how to get your physiology under control, to managing people better by understanding how to coax the best performance out of them.

More Examples

Cortisol levels and negative emotions are not straightforward and directly correlated (reference). Hopefully, this example has helped to highlight just how complex this interplay of biological processes and chemicals really is. This is one reason that using drugs can be destructive. It’s why nootropics, unfortunately, are not the answer. You can take a 5-HTTP supplement (5 hydroxytryptophan) in order to become more socially relaxed, but that is also going to risk making you a little slower (seeing as serotonin and melatonin are both inhibitory substances), and affecting your appetite and sleep/wake cycle.

The same goes for modafinil, often called the “real Limitless drug.” Claims that this medication is without side-effects are drastically exaggerated. Modafinil works on orexin and dopamine, which in turn regulate sleep/wake cycles alongside bowel movements, energy levels, appetite, and more. It’s no wonder then that a powerful drug that prevents sleep will ALSO suppress appetite and force you to keep running to the toilet. Or that it dries out your mouth and makes you grind your teeth.


All these cycles are linked. And what bodybuilders think of as “catabolic” and “anabolic” states, are actually the same thing as “fight or flight” and “rest and digest.” The brain and the body work in constant tandem.

Hacking Your Physiology

While taking Adderall to boost your focus is not a physically intelligence solution to your problems then, there are other, safer ways to “hack” your physiology to ensure you perform optimally when you need to.

Any one of the below suggestions could be the subject of its own post, but here are just some examples of controlling your physiology:

  • Splashing your face with cold water to activate the mammalian diving reflex
  • Taking a cold shower to increase alertness
  • Using “power poses” although not all studies have been able to verify how effective this strategy is. Certainly, there is merit to changing your own body language.
  • Avoiding light from screens just before bed to avoid spiking cortisol
  • Drinking coffee to boost alertness
  • Knowing when to stop drinking coffee
  • Changing your physiological state and mood by listening/dancing to music. This is ideal for getting more energy when you need to be more productive but you’re beginning to flag.
  • Fasting to increase physiological arousal and focus
  • Using the fourfold breath to stay calm
  • Wide-angle vision to achieve a meditative/flow state
  • Basking in sunlight to help reset your biological clock after travel
  • Remembering to actively relax muscles during tense moments
  • Manipulating meal timings to mitigate the effects of jetlag
  • Using spaced learning to drastically increase skill acquisition and memory
  • Using contrast therapy to enhance recovery
  • Exercising throughout the day – this has been one of the most profound changes I’ve made in my own life and it has transformed my own energy levels. Performing pull ups and push-ups continuously ensures that I don’t suffer from “sensory motor amnesia,” while keeping my metabolism up, and increasing strength.

Biohacking and Physical Intelligence

In each case, you are listening to your own body and combining this with a knowledge of how it works in order to eke out greater performance and even happiness.

Just be wary of some “biohacks.” I want to make a post on biohacking in future, but suffice to say that not all advice you hear from biohacking “gurus” is equally as effective. Some of these strategies are expensive and time-consuming for very little reward, others are based on poor understanding of science and can even be harmful.

Biohacking Physical Intelligence

A great tip my friend gave me for being more productive in the evening, was not to sit down and eat until I’d accomplished everything I wanted to for the day. The minute you sit down and eat a whole bunch, you’re going to struggle more to motivate yourself and get up.

Individual Differences

It’s also useful to recognize that everyone is different. Some people don’t get hangry so much as nervous, or shaky (that’s me). Physical intelligence also means knowing how you personally respond, and thus acting ahead.

For example, if you know that you start getting hangry about 3 hours after a big meal, perhaps that could help you to plan out your meals a bit better on a big day.

We can likewise think about chronotype in this context. Different people function better at different times of day. In one study, 100 meter race performance varied as much as 26% based on the individual’s chronotype and the time of day the run took place (report). Knowing this about yourself can help you to plan ahead: when are you most effective in the gym? When do you need to take a break?


How far ahead of your training should you eat? How can you improve your energy levels so that you wake up in the morning full of life? I’ve recently become much more productive since cutting my caffeine intake at around 1pm. I guess I’m actually sleeping properly now!


Another crucial takeaway from all this is that you need to understand that your energy levels are finite. You’d be surprised just how little respect many people give to this – which just tracks back to a very limited physical intelligence.

The most obvious example of this comes when someone decides to start working out and so adds a plan consisting of four weekly workouts. They haven’t had the energy to train at all until now, and yet they anticipate they’ll have the energy to add four hours of training plus two hours of commuting and one our of showering every week.

Twisting Workout

I always say this: you probably have enough time to workout. Or to start a business.

What you lack is the energy to do so. If you have watched an entire boxset of something on Netflix in the last few weeks then you know this is true. The problem is you’re too burned out after a packed, emotionally-tiring week, to be able to summon the energy to train.

So, if you want to be successful with a new training program, you need to first get the energy back and/or be less ambitious with your training goals.

Motivation and discipline themselves require energy?

Did you know that motivation and discipline themselves require energy? The more tired you become, the less capacity you have to train in spite of that tiredness. (Interestingly, tiredness also makes us far more impulsive and even less moral!)

Managing Energy

In sports and martial arts, you need to be able to managefatigue and respond to it on the fly, then strategize in order to sustain yourself long enough.

Managing Energy

The goal of a cyclist is not to stay in the lead the entire way around the Tour de France. That would likely involve expending too much energy early on and thus losing toward the end. Rather, the goal is to manage the precise amount of exertion at any given point in order to ensure the highest average speed overall. To do this, the cyclist needs to be able to respond to the way they are feeling on the day in real-time.

I screwed up when I ran the marathon by letting my sodium dip far too low. Unfortunately, I had no way to control this at the time as I had nothing salty on me!

Psychomotor Vigilance

In a recent Instagram Live, JC Santana told me about his approach to training psychomotor vigilance. In an MMA contest, losing concentration for even one second can end a fight. The brain must act as a constant Bayeseian probability machine to anticipate how the opponent is going to move before they even throw that punch or kick.

The brain must act as a constant Bayeseian probability machine.

This requires tremendous energy, and of course that focus and the apparent reaction times suffer as the fight drags on. That’s why JC and his team at the Institute of Human Performance are currently heavily focused on this aspect of training: traing their athletes to remain vigilant even in the face of physical fatigue and mental stress. There are obvious benefits to this kind of training for the rest of us too: as anyone who has ever felt sluggish after a three-hour drive will know.

Even strategy comes into this: learning how to strategically grab moments of rest and recovery even during a fight, for example!

A Link With Proprioception

Interoception is just one of the senses that we often overlook. Another is proprioception: or body sense. This is our kinesthetic awareness, our knowledge of where our body is in space at any given time, our distribution of weight, and the tension we might be carrying in our muscles. Proprioceptive feedback comes from a number of different sources, including the golgi tendon organ that provides information about muscle tension/contraction, and the muscles spindles that tell us about muscle length.

Interoception and Proprioception

Interoception and proprioception are extremely closely linked and in many cases the line is blurred. Suffice to say though, that in many cases, improving proprioception will improve interoception – and vice versa.

For example, many people carry a lot of stress with them but don’t even realize it. As we know, a fight or flight response increases muscle tension in order to prepare for sudden action. This is not helpful at the desk, or when trying to sleep.

And so we sit there, with jaws clenched, and shoulders raised. This can lead to pain and discomfort, but it can also further elevate stress, seeing as the communication between these signals is two-way. Being stressed makes us clench up, and being clenched up makes us more stressed.

Remember to Breathe!

Often then, improving your state of mind and health, can be as simple as becoming mindful of that tension, and releasing it.

Interoception AKA Physical Intelligence is the ability to sense and even control physiological states. This post explores how we can use and develop this capacity.

So I ask you: where are your shoulders right now? Are you clenching your jaw? Even if you don’t think you are, try actively relaxing and you might be surprised how much more relaxed you could have been.

Where are your shoulders right now?

This, of course, can be highly beneficial for athletes. Wasting energy by walking around like a giant clenched-fist is not conducive to optimal performance! This is particularly true in martial arts – my Tai Chi instructor used to dismay at my constantly-tense shoulders. They blamed my bodybuilding at that time, but the truth was simply that I didn’t know how to control that tension. I’m still working on it.

Personality and Performance

Even personality has an impact here. A huge impact in fact. There are many different aspects of personality that contribute to physical performance, adherence to training, and even the physiological impact of training (study). Want to know something crazy-but-logical-when-you-think-about-it? Extraverts actually have faster reaction times according to multiple studies (reference)!

Physical Intelligence Proprioception

I’ve discussed in the past how the ability to become alert-yet-calm in response to stress appears to be linked to the production of neuropeptide Y and DHEA to mitigate the effects of cortisol on the hippocampus. This is can directly predict the performance of high level athletes and infantry.

In order to get the very most performance out of yourself, working on your personality – which is mutable to an extent – might well be compulsory. Remember, as I often say, there is no one “perfect” brain state. The perfect brain has the ability to shift between states as needed.

Muscle fatigue is also an aspect of both proprioception and interoception working together. That feeling of having heavy, tired muscles is one that can prevent us from completing a workout.

Where Does Interoception Come From?

But does interoception come from?

Of course, interoception is the result of many different systems working together. An obvious culprit is the vagus nerve, which handles communication between autonomic functions and the brain. This is how breathing rapidly is able to alter stress levels, for example.

Proprioceptors of Visceral Fascia

Then there are less direct connections: such as the aforementioned role of tryptophan after eating. And we know how gut bacteria can likewise contribute to the production of neurotransmitters that alter mood and even metabolism.

See also: Superorganism: Microbiome Brain, Performance, and Health Effects

The anterior cingulate cortex appears to be one of the brain regions most responsible for mediating interoceptive attention (reference). This area works alongside the insula of the cerebrum, which is responsible for the sense of self and emotional state.

The Role of Fascia

But one of the most surprising sources of interoception is the fascia.

(You didn’t think I was going to go a whole post without mentioning fascia did you?)

Fascia, as I’ve discussed on The Bioneer before, is a kind of “sheath” of connective tissue that is found throughout the human body. Fascia has been gaining a lot of attention in recent years. Whereas it was once thought to be a kind of inert “stuff,” we now know that it contains its own smooth muscle cells that may help contribute toward healthy movement. Even more fascinating, is that it is actually riddled with nerve endings. Many of these nerve endings are proprioceptors, suggesting that the muscle fascia may contribute to the mental model we carry of our own body. But we now also know that the fascia likely contains 7 times more interoceptors (reference).

Fascia and Interoceptors

These are free nerve endings that have countless crucial roles: among which is to provide feedback regarding states such as hunger and warmth and to regulate emotional responses. In fact, the human visceral fascia, which helps to suspend organs within their cavities, contains countless nerves that link directly to the insula – showing how things like hunger and fatigue can impact directly on mood.

These sensations are also used in our development of “gut feelings” and intuition, handled by large and densely connected brain cells called “spindle cells.” The cells are considered crucial for social abilities but are also key in steering behavior based on visceral reactions.

And similar abilities of the superficial fascia show us why massaging, hugging, stroking, and tickling can all result in emotional responses.

Interoception and Context

These signals are then interpreted in a highly context-sensitive manner. That is to say, that a light stroke on the leg can be interpreted as arousing, ticklish, or deeply upsetting depending on context. The same goes for your sense of fatigue or arousal.

These signals are then interpreted in a highly context-sensitive manner.

And this is one reason why you can quickly make someone extremely angry by asking them “why are you so angry today?”

(This is an example of biohacking another person!)

Tom Myers, in a conversation with Dr. Robert Schleip, gave a fascinating example of keeping your arm raised for a long period of time. Proprioception is what tells you where your arm is, but the overwhelming urge to lower the arm as it gets tired is controlled by interoception. This is emotional and based on senses such as heat and hydrogen build-up. This is something that bodybuilders should be all-too familiar with!

Curling Barbell

Myers went on to described this as a kind of battle against your own interoceptive feedback. Who wins? The fascia telling you that you need to eat? Or your own will?

A key takeaway here is that all of these systems are linked and intertwined. Everything from our personality, to our physical strength, to our reaction times, to our gut bacteria, to our proprioception, to how hungry we are, to the environment around us. There is constantly communication between all of this shifting and changing systems. A truly transformative training program should recognize the system as a whole.

How to Improve Interoception

So, with all that said, how can you improve your interoception and your ability to recognize what your body is telling you so that you can work with it rather than against it?

Exercising and especially improving proprioception can also help a lot. As we’ve seen, this is very closely linked with interoception and will help to give you greater awareness of your own body in general.

Improving Proprioception

Using biofeedback is another great strategy. That means using heart rate monitors and fitness trackers to tell you how things like heartrate are changing. By being aware of this, you can then learn to recognize the cues from your body without those devices.

Meditation, of course, can also help us to choose how to focus our attention and to work through certain sensations where appropriate. Cognitive Behavioral Therapy can help us to change the context of sensations in order to manage our emotional responses to them.

But the rest is learning. The more you understand about the way your body works and the different physiological systems involved, the more you can intellectualize the sensations you are interpreting.

Hopefully, you will leave this post a little more physically intelligent and aware of your interoception than you began.

About Adam Sinicki

Adam Sinicki, AKA The Bioneer, is a writer, personal trainer, author, entrepreneur, and web developer. I've been writing about health, psychology, and fitness for the past 10+ years and have a fascination with the limits of human performance. When I'm not running my online businesses or training, I love sandwiches, computer games, comics, and hanging out with my family.

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