HSP literature often uses the term overarousal to discuss the HSP experience, this can be confusing to those who do not experience high sensitivity. I prefer the term overstimulation, as it is descriptive of the biological process of stimulation to the central nervous system (CNS). In order to better understand overstimulation, let’s start with a simplified version of the CNS, which is made up of your brain and spinal cord. The CNS is essential in processing all forms of input, from things you register consciously (e.g., thoughts, movements, and emotions) and things that occur without your awareness (e.g., breathing, heart pumping, hormone regulation, and temperature regulation) (Newman, 2017). The CNS is also where all five senses are processed, which is key to how an HSP experiences the world differently than a non-HSP. When there is too much information to process or something registers as “wrong” in the body, your CNS will begin efforts to regulate back to a calm and even state of functioning. An international group of researchers reviewed the multiple functional MRI (fMRI) studies on HSPSs that have been conducted to date. Consistently, the different brain structures measured in these studies showed up as more active in HSP populations than in non-HSP populations (Greven et al., 2019). In short, the CNS of HSPs are registering and responding to more data than for non-HSPs (keep in mind that more does not always mean better, it’s just different).

Everyone has limits to what their CNS can handle and can reach a point of feeling overstimulated. For example, everyone has different ideal temperatures for working and will feel too hot or too cold at varying rates, eventually hitting a temperature where they become sluggish, distracted, and/or unable to work in their normal fashion. The ideal temperature for an HSP might be much more specific than for a non-HSP. The heightened sensitivity of HSPs essentially means heightened processes of the CNS, as shown in the fMRI studies. While this carries benefits for HSPs (e.g., depth of understanding, empathic connection), it also means it is easier to hit limitations and experience distress and decreased functioning.

With any stimulus, the CNS of an HSP is processing at a deeper level than that of a non-HSP. This can be exhausting for HSPs, as the entire brain and spinal column are processing large amounts of data all the time. If you are running multiple complex processes on a computer, you might expect that its efficiency occasionally decreases. It can be the same for people when their brain structures are more active—think of HSPs as running more complex apps than non-HSPs. This is why you might pause before answering a question or need to wait until you are in a quiet office before responding to emails—there is too much data to process!

Your CNS is constantly digesting data and then responding to help regulate your body. A regulatory response—for example crying, which releases stress hormones like cortisol—is one that helps bring the CNS back into balance. Having a compassionate response toward yourself as your body works to find a regulated balance of CNS functioning can be helpful even if you cannot change the stimulus throwing it out of balance. Other CNS responses such as flushing (skin redness) and heart palpitations are your body’s ways of regulating overstimulation. Mindfulness practices can be crucial in learning how your CNS responds and giving space for self-regulating practices of the body. How can you take a moment today to practice mindfulness?

Citations:

Greven, C. U., F. Lionetti, C. Booth, E. N. Aron, E. Fox, H. E. Schendan, M. Pluess, H. Bruining, B. Acevedo, P. Bijttebier, J. Homber. 2019. “Sensory Processing Sensitivty in the Context of Environmental Sensitivity: A Critical Review and Development of Research Agenda.” Neuroscience & Behavioral Reviews 98 (March 2019): 287-305.

Newman, T. “All about the Central Nervous System.” Las modified December 22, 2017.