How stress and trauma live in the body

Past trauma shapes how we react to threats. Cleveland Clinic gives the example of someone who was in a car crash feeling the alarm go off when getting into a car, even though that moment is safe.

The Trauma: what it is & how it affects you guide covers fight, flight, freeze and fawn, triggers and the window of tolerance. This guide goes further into how the body’s systems work, where stress shows up, and which popular claims hold up.

Please see your clinical provider about new or ongoing symptoms, and tell them about stress or trauma too. The VA encourages telling all your providers about both pain and PTSD so care can be joined up.

During fight or flight, the body pauses jobs it doesn’t need for instant survival, like digestion and repair, so energy can go to muscles, heart and lungs.

That is why stress can show up as stomach trouble or feeling run down. The When the body speaks guide has a full tour of where stress shows up.

The stress response is meant to turn on, deal with danger, then turn off. The body usually needs 20 to 30 minutes to calm down after a big surge.

NIMH lists being easily startled, feeling tense or on edge, and trouble sleeping among the reactions people with PTSD can have. These “arousal” reactions are often constant, rather than coming and going with reminders.

People with PTSD may keep feeling stressed or frightened even when they are not in danger.

Research links chronic stress to high blood pressure and changes in the brain associated with anxiety and depression. Repeated adrenaline surges can strain blood vessels.

Long-term high alert can weaken the immune system and add to anxiety and low mood.

Sights, sounds, smells or body sensations linked to a past event can switch the alarm on fast, before you have time to think. The Trauma: what it is & how it affects you guide explains triggers in detail.

Above the window, the accelerator is pressed hard. You may feel on high alert, irritable, flooded or panicky, and it can be hard to think clearly.

Below the window, people feel numb, frozen, foggy or shut down. Some feel disconnected from their body or surroundings. This is a protective response, not laziness or not caring.

A goal of trauma care is to widen the window, so ordinary stresses don’t knock you out of it so easily.

The VA says almost everyone with PTSD has trouble sleeping. Feeling the need to stay on guard, being startled by noises, fearing nightmares, and worries that surface at night can all keep sleep away.

CBT for insomnia is the recommended first step, helping about 7 in 10 people who complete it, usually in about six sessions. Using alcohol or drugs to sleep can make things worse.

The VA explains that pain can remind someone of a trauma, and that being on high alert can make pain and a racing heart more noticeable. Both disturb sleep, and both can lead to doing less and feeling lower.

Trauma-focused therapy can help PTSD and may also improve how people manage pain day to day. The Chronic pain guide has more.

The stress response gets muscles ready to act. When it stays on, people often notice tension, trembling, a jaw or shoulders that won’t relax, and a strong startle.

Because digestion is paused during fight or flight, ongoing stress can show up as stomach aches or bathroom changes. When the body speaks covers the gut–brain connection in depth.

Cleveland Clinic explains that anxiety can lead people to read harmless body sensations as threats, which can bring more symptoms and stress. Being on high alert after trauma can make sensations like a racing heart more noticeable too.

PTSD is among the conditions that may affect interoception. Some people notice hunger, tiredness or pain late, or feel numb.

Cleveland Clinic lists slow breathing, mindfulness, yoga and CBT as ways people build interoception, ideally with guidance from a health professional.

Start small and outward if inward focus feels too much. The Somatic (body-based) therapy explained guide describes therapies that focus on this.

A 2025 review of 122 claims from the popular book of that name found that its key claims, that trauma damages the brain and that body-based treatments work uniquely well, are not supported by the current weight of research.

A 2026 opinion article argued that the body doesn’t literally store trauma. Instead, the brain keeps predicting danger and the body follows along. The authors agree that body states matter in trauma.

Somatic Experiencing teaches that an unfinished freeze response leaves survival energy “bound in the body”, which can be released through shaking or trembling. This is the method’s model.

A 2021 review found only preliminary evidence that SE works, and it didn’t test whether this explanation is correct.

Polyvagal theory, developed by Stephen Porges, links parts of the vagus nerve with feeling safe, social or shut down. Its ideas are often mentioned in therapy and self-help.

In 2023, researcher Paul Grossman reviewed its five core ideas and argued that each is either untenable or highly unlikely, based on existing research.

Simple ideas like “accelerator and brake” are still a useful way to talk about the nervous system. Just be wary of “vagus nerve hacks” sold as cures.

• Fight-or-flight is a real body response
• Chronic stress is linked to physical health problems
• Trauma reactions often include sleep trouble, tension and startle
• Well-studied therapies help many people recover

The VA highly recommends trauma-focused talk therapies for PTSD. Cognitive Processing Therapy, Prolonged Exposure and EMDR have the most support.

Prolonged Exposure also teaches a breathing skill, so body work is part of proven care too. See Therapies for trauma.

Exercise like a brisk walk can ease muscle tension. A 2025 review of 14 trials found exercise reduced PTSD symptoms compared with control groups.

Harvard Health describes the “relaxation response”, using slow belly breathing, imagery, repetitive prayer, yoga or tai chi to counter stress. It may be worth trying, though it is not a cure-all.

Body-based calming skills you can try today has step-by-step skills.

Close relationships with family and friends can help people cope with ongoing stress, according to Harvard Health.

CBT for insomnia can be done in person, by video, online or with the CBT-i Coach app. It can also reduce nightmares and the distress they cause.

• Ask how you can help, rather than guessing
• Agree that either of you can call a time-out during conflict
• Do active things together, like walks or bike rides
• Learn about trauma reactions

Try saying

• “You’re safe right now. I’m here.”
• “Do you want space, or company?”
• “Your body’s been through a lot. It makes sense.”

Try not to say

• “It’s all in your head.”
• “Why are you so jumpy?”
• “Just relax.”

The VA encourages family members to keep their own friendships and hobbies, take quiet time, and see a provider if they feel sad or hopeless for a long time. If anger ever turns violent, go somewhere safe and get help.

Your primary care provider can check body symptoms and refer you to a trauma-informed therapist. FindTreatment.gov is SAMHSA’s locator for mental health services.

Veterans can reach the Veterans Crisis Line by calling 988 and pressing 1, or texting 838255.

Find A Helpline lists free, confidential helplines in more than 175 countries. In an emergency, contact your local emergency number.