Everything starts with the body - including, and especially, our mental health.
I spent the past decade studying how we integrate information coming from different sensory modalities - vision, touch, internal senses (interoception for the nerds) - and how this shapes our mental health and health at large. I wanted to understand what makes us feel like us; that our body belongs to us, that we are the ones experiencing and feeling. And I wanted to find out what helps us get back on track when we don't feel like ourselves anymore. I worked with different kinds of tools (behavioral experiments, neuromodulation, digital tools like apps) and different types of people - patients with strokes, students with high anxiety and depression, healthy participants.
One would think that what makes us us is so deeply rooted, so important in defining us that it is almost impossible to shake it. Instead, what this decade of research has taught me is that our sense of self is not a static thing, but rather it is continuously and inherently shaped by the context we are in.
A very clear example of this is the famous Rubber Hand Illusion. When a fake hand is positioned in front of someone and their real, hidden, hand is stroked at the same time, that person will likely believe the fake hand belongs to them. And this remains true even if they are perfectly aware that they are looking at a fake hand. In this video, the researcher hits the fake hand after participants have “embodied” it - and the fear is as real as if the hand hit was their own.
What is even more interesting is what happens when, as a result of dramatic changes in our brain, we stop feeling that our body belongs to us. I ran experiments with patients affected by strokes in the right side of their brain - think of this area as a processing station, where all the different information (visual, tactile, etc) is combined to give us the feeling that our body is indeed ours. Whilst these patients could not recognize their own hand or leg as belonging to them, they would immediately and easily embody a fake hand positioned in front of them.
What this tells us is that the brain is flexible and is constantly trying to make sense of what’s in front of us. There is a disconnect between the patient’s hand attached to their body and the processing of that hand; yet the fake hand does not have that same problem, so it is recognized as a plausible hand to feel as their own.
The same is true when you use electrical stimulation to “fake” a disruption of the normal sense of self. The way participants embody a fake hand is different when they are exposed to a light current on their scalp that interferes with the processing station mentioned above.
So what does this mean?
The way we perceive our body can change according to the context in which we perceive it, may it be a temporary manipulation or a long-term change in our brain structure that doesn’t allow us to feel our body as we used to.
And the pipe works both ways. When this context is too much, we even have fail-safe mechanisms to prevent it from damaging us. Depersonalization Disorder (DPD), a condition that leads people to feel disconnected from their own bodies, is a prime example of this. It is described as if the world and one’s own body are suddenly opaque, perceived indirectly, almost two-dimensional - like the mind and the body are not connected, but distinct, separate entities.
Several research groups (including mine) have suggested that depersonalization may be the result of our brain shutting down information that is too difficult to process. When people find themselves in situations that are emotionally overwhelming and considered inescapable, they may silence certain signals in favor of other, easier to process, senses (like vision). This makes a lot of sense: when we are cornered, the instinct is to find any way to escape a situation we find unmanageable. The result of this however can lead to extreme compensation, which makes us unable to be in tune with our bodies and has a severe impact on our mental health.
Similarly, when we are in situations of extreme stress, we may shut down signals from our body (like pain) because they interfere with our immediate goals. In a recent research study, we looked at the relationship between reports of stress and pain in users of a popular health app residing in Ukraine at the start of the Russia-Ukraine conflict. We found that the relationship was an inverse one - users reporting high-stress levels also reported lower instances of pain. This is again intuitive: if you are fighting for your life, you need to shut down everything that does not help you reach safety immediately. However, if we think about what this means for our everyday life, it paints a much more complex picture - stress can shape the way we perceive our own body long-term (and vice versa).
Despite my research, the fact that everything starts with the body did not click on a personal level.
Until one day my academic self met my mundane self. I was living disconnected from my body. Drinking too much, eating erratically, battling insomnia. I was living on adrenaline and caffeine - and it was not a healthy living to say the least.
Then I picked up outdoor running and everything changed. My sleep, my nutrition, everything fell into place. And I started wondering why exactly that was the case.
Exercise, especially outdoor exercise, can help us stay connected with our bodies
We need nurture the relationship between mind and body (which is not really a distinction, but more like a continuum) and we do so by making sure we are in tune with it.
Exercise is a powerful tool to achieve this. It makes us aware of our body in ways other things do not - when we exercise we are moving muscles in our body that we are not used to moving or perceiving. We need to be careful of our surroundings and we need to strike a balance between pushing and maintaining. It’s not a surprise that exercise is a powerful mood-booster and stress-reliever. It even improves our attention and cognition - it gives us an opportunity to feel our bodies in a different way. Exercising outdoors provides us with a sense of connectedness with the world around us and makes it more likely for us to enjoy ourselves, meaning we will want to do it again. Exposure to sunlight and natural elements have a proven effect on our mental health and are a powerful stress regulator.
Our sense of self, and how we feel about ourselves and the world, changes with the context we are immersed in - the ability of our perception to be shaped by the world and by our own experience is crucial to adaptation. Which is why it’s important to provide ourselves with ways to stay connected with our bodies, with regular movement and exercise being a crucial in achieving this.
Post by Sonia Ponzo, PhD
References and reading:
Ponzo, S. Balancing interoception and exteroception: vestibular and spatial contributions to the bodily self.
Ponzo, S., Kirsch, L. P., Fotopoulou, A., & Jenkinson, P. M. (2018). Balancing body ownership: Visual capture of proprioception and affectivity during vestibular stimulation. Neuropsychologia, 117, 311-321.
Khalsa, S. S. et al. Interoception and Mental Health: A Roadmap. Biol Psychiatry Cogn Neurosci Neuroimaging 3, 501–513 (2018).
Saini, F., Ponzo, S., Silvestrin, F., Fotopoulou, A. & David, A. S. Depersonalization disorder as a systematic downregulation of interoceptive signals. Sci Rep 12, 22123 (2022).
Kazlou, A., Bornukova, K., Wickham, A., Slaykovskiy, V., Peven, K., Klepchukova, A., ... Ponzo, S. & Garfinkel, S. (2024). Effects of stress on pain in females using a mobile health app in the Russia-Ukraine conflict. npj Mental Health Research, 3(1), 2.
Wicks, C., Barton, J., Orbell, S., & Andrews, L. (2022). Psychological benefits of outdoor physical activity in natural versus urban environments: A systematic review and meta‐analysis of experimental studies. Applied Psychology: Health and Well‐Being, 14(3), 1037-1061.
Boere, K., Lloyd, K., Binsted, G., & Krigolson, O. E. (2023). Exercising is good for the brain but exercising outside is potentially better. Scientific Reports, 13(1), 1140.
Loureiro, A., & Veloso, S. (2017). Green exercise, health and well-being. Handbook of environmental psychology and quality of life research, 149-169.
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