You’ve probably heard the phrase “trauma lives in the body.” It’s not exactly a new concept, but in recent years, thanks to researchers and clinicians like Bessel van der Kolk (The Body Keeps the Score) and Peter Levine (Somatic Experiencing), the idea has gained scientific grounding and public recognition. We now have compelling evidence that what happens to us doesn’t just live in our memories – it shapes our brains, our nervous systems, and the very way our bodies function.
According to the World Health Organization, around 70% of adults worldwide report experiencing at least one traumatic event in their lifetime. What counts as “traumatic” can vary widely – what overwhelms one person may not overwhelm another – but that isn’t really the point. The point is that the vast majority of people have lived through something that changes their physiology. Trauma isn’t rare – it’s actually a shared human experience.
THE BRAIN
When we experience trauma, the brain’s alarm system (especially the amygdala) goes into overdrive. The amygdala is responsible for detecting threat and activating our survival response (otherwise known as fight, flight, freeze). At the same time, the prefrontal cortex (the part of the brain that helps us think logically and assess risk) can go offline. This means that even years later, if a reminder or “trigger” activates that memory, the brain may react as though the danger is happening all over again.
Researchers like van der Kolk emphasize that traumatic memories often aren’t stored in the same way as ordinary memories. Instead of being filed neatly in the brain’s hippocampus (the part of the brain responsible for narrative and context), fragments of traumatic experience can remain sensory, bodily, and non-verbal. That’s why someone might feel their heart race, palms sweat, or stomach tighten without fully understanding why.
THE NERVOUS SYSTEM
The nervous system plays just as big a role. Trauma can leave the autonomic nervous system (which is the body’s regulator of arousal) stuck on “high alert” (hyperarousal) or “shut down” (hypoarousal). Hyperarousal shows up as difficulty sleeping, jumpiness, irritability, or constant scanning for danger, whereas hypoarousal shows up as numbness, fatigue, disconnection, or feeling “frozen.” Sometimes people confuse these nervous system states with emotions like anxiety or depression – hyperarousal can feel very similar to anxiety, and hypoarousal can look and feel a lot like depression. While they are closely related, understanding them through the lens of nervous system response can provide a clearer picture of what’s happening internally.
This is where the work of pioneers like Peter Levine, founder of Somatic Experiencing, becomes so important. Levine observed that when animals in the wild face life-threatening situations, their nervous systems go into high activation (just like ours do!) but after the danger passes, they instinctively release the survival energy through shaking, trembling, or movement. Humans, on the other hand, often don’t get the chance to complete that cycle. If we couldn’t fight back or escape during a traumatic event, the body may hold on to that unfinished survival energy. Over time, that “stuck” energy can show up as chronic muscle tension, pain, panic attacks, emotional reactivity, or a sense of being frozen.
Levine’s work emphasizes that healing doesn’t always come from retelling the traumatic story but from helping the body gradually and safely discharge this stored survival energy. By gently reconnecting with bodily sensations in a controlled, supportive way, people can begin to restore balance to the nervous system and reclaim a sense of safety.
Put simply: trauma changes how both the brain and the body operate. It’s not “just in your head” – it’s in your whole system. If this idea feels new to you, give yourself some grace. Take in this information as knowledge that can help you better understand what may be happening in your body and mind. Gaining new insight into the physiology of trauma can be powerful – it can shift the way you see yourself, and open the door to new paths of healing.
