In EMDR and trauma therapy, one of our most important clinical concepts isn’t a technique—it’s a lens. The window of tolerance, first introduced by Dr. Dan Siegel, helps us assess whether a client is emotionally regulated enough to engage in trauma processing.
A well-paced EMDR session is one in which the client is supported to work close to their emotional edge—without falling off it.
What Is the Window of Tolerance?
The window of tolerance refers to the optimal arousal zone of the nervous system. Within this zone, clients can tolerate distress without becoming overwhelmed (hyperaroused) or disconnected (hypoaroused); they maintain some contact with the present and some contact with the trauma memory.
When clients are outside of their window of tolerance, they may:
- Become flooded with emotion
- Dissociate or disconnect
- Shut down verbally or physically
- Loop, stall, or derail during reprocessing
Why It Matters in EMDR
EMDR uses bilateral stimulation (BLS) to support the brain’s inbuilt default adaptive information processing (AIP) system to keep the learning from a traumatic experience while losing the disturbance. This system only works when the client is grounded enough to access and integrate the memory—without being hijacked by it.
In monitoring the client’s arousal state, we ask: Are they inside their window of tolerance? Do they have the resources to return if they step out? What will they need if they can’t?
A well-paced EMDR session is one in which the client is supported to work close to their emotional edge—without falling off it.
The Therapist’s Role in Supporting the Window
Supporting the client’s window of tolerance means:
- Resourcing when needed
- Adjusting pacing, language, and intervention style
- Tracking subtle signs of hypo- or hyperarousal
- Attuning moment-by-moment to the client’s state
But there’s another piece that’s rarely named—and it deserves just as much attention: our own window of tolerance as therapists.
Up Next: Part 2: What About Our Window of Tolerance?
As we track our clients’ regulation, we also need to track our own. EMDR sessions can be activating—not just for clients, but for us. What happens when the material in the room pushes us outside our emotional range? How do we stay well and effective in the long term?
EMDR training can be undertaken by a range of clinical disciplines. I invite you to join us in learning EMDR. Course details and eligibility can be found on our EMDR training page.
Have more questions about EMDR? Read some of our previous blog posts or head over to our page of Frequently Asked Questions (FAQs)!
